Blowing fuses

[Leigh Betsch]

I installed a new Clear Vue cyclone with a 5 hp 20.8 full load amp motor last week. I thought I should install a safety disconnect switch similar to the attached photo because it is 80 ft from the main panel and I wanted to have a quick way to kill the power if I needed to. I put a fused safety switch in that has 2 30 amp fuses like the other attached pic. I used 10/2 + G romex cable. The problem is I blow the fuses when the motor starts up once in a while. These fuses are "T" time delay fuses for motor circuits. I measured the running amperage at 13.5 amps. I'm wondering if I undersized my switch and maybe I should have a switch that takes those 30 amp 250 volt cartridge fuses instead of the 30 amp fusetron ones. Or maybe I should have use 8ga and a 40 amp fused switch. Any ideas?

[Tom Veatch]

My cyclone probably uses the same motor - Leeson 5HP, 20.8A FLA - hardwired into the circuit through a disconnect. But my disconnect isn't fused. The catalog listings I've seen, use the phrase "For Normal Duty Motor Load" in the description of the time delay Edison base plug fuses. My guess is that, since the motor has to spin up that high inertia blower wheel, the startup inrush lasts longer than that type fuse expects.

My ignorance of fuses knows no bounds, but is there another plug type fuse with a longer delay time? If not, and you insist on, or local codes require, a fused disconnect, you may have to replace the disconnect with one that uses the cartridge type fuse.

If local codes don't require a fused disconnect, don't use one. Your circuit breaker provides protection against wiring overload and that motor, if it's the one I'm thinking, contains a resettable internal overload breaker so you're well protected without fuses in the disconnect.

Edit: Did a little research, and if you have to have fuses in the disconnect, I think you need something like a class RK-5 Cartridge fuse (http://www.omega.com/Auto/pdf/ECNR_ECSR_LENRK_LESRK.pdf)- 30 amp size will carry 150 amps for 10 seconds which will get you past the inrush. And, based on a couple of years experience with that motor on a 30 amp circuit, correcting the fuse blowing won't shift the problem to a tripping breaker. A 30 amp residential class breaker has never had a nuisance trip starting my 5HP cyclone.

[Jeff Bratt]

Well, I don't have an answer, but I did find some information, and now have a couple more questions. First - the fuse data sheet is here (http://www.cooperbussmann.com/pdf/04a56af6-62e3-41ce-a20d-ef0beae33d14.pdf), and I'll assume the SquareD switch is this one (http://www.schneider-electric.us/products-services/products/safety-switches/general-duty-safety-switches/#tab=1), or something equivalent. The current rating on the fuse is fine for the motor, but Bussman specifically rates this as a 125V fuse. You are switching a 240V motor, and I don't know how the connections are made inside the switch, or how 120V fuses would fit into this picture. Also, why are you using a fused disconnect switch in the first place?

[Tom Veatch]

Looking at Jeff's data, I read the time/current curve as blowing a 30amp fuse at about 1 sec and 125 amps. I wouldn't be surprised at 125 amp inrush on that motor (appx. 6 x FLA). I'm not going out to the shop at 3 a.m. to time the startup of my cyclone, but memory is telling me the spinup time is appreciably more than a second before the centrifugal switch on the start cap opens. (It's spinning one of the ClearVue 16" impellers)

Since each fuse is only seeing 120v to ground - same as it would in the hot leg of a 120v circuit - the 125v rating may be OK (?????)

I'd interpret the time delay curve as saying your fuses are marginal to inadequate for the application and echo Jeff's question - "Why are you using a fused disconnect?"

[Tom Godley]

Unless you have some type of restriction in one part of your system that is causing the motor to overload on startup, I bet the time delay of the fuse is not long enough when the motor spins up on occasion. Does it happen mostly when using one location?

The cartridge type do allow for a greater variety of fuses - not sure what is available in that type to allow for a slightly longer inrush.

Without using an accurate fuse for the application you will not get any benefit using a fused disconnect vs an unfused. If you are getting a restriction from someplace, than the fuse blowing is doing exactly what it is supposed to do.

The internal overloads inside most general duty motors are to prevent a fire - when the overload does trip the motor has usually been permanently damaged.

The 125v is correct -- that is all that it carries

[Rollie Meyers]

Edison base fuses are prohibited on new installs, they are only allowed in existing installations where there is no overfusing, what this boils down to is type S adaptors are required in a Edison base fuse holder if a new installation.

A 60A switch w/ 35A dual element (time delay) fuses will prob cure the issue, a non-fusible disco (assuming there is a breaker ahead of it) or a 2-circuit loadcenter & a 30A breaker are other options. Fusible & non-fusible pullout A/C disconnects are cheap, ($8.00 or so),at big box stores.

[John Coloccia]

This motor doesn't use a neutral, so the potential on the line is a full 240V and needs to have a 240V fuse. Fortunately the voltage ratings are very conservative so when the 120V fuse blows, it's not turning into a little plasma torch :eek:

I'm assuming that you have the motor on a remote, and that's why you're concerned about having to kill power (i.e. no hard switch?). If so, me too. What I did on mine is I ran a neutral to power the 120V remote and relay. That part of circuit is protected locally with a 15A combination fuse/switch (you can get them at the Borg). I did that to protect the wiring inside the remote reciever, which I assumed is not designed to survive a 30A short. A side benefit is if I need to kill power to the cyclone, I can hit the switch and that will open the relay. I've had to do that once when my remote battery died. It's not a true disconnect, but it does what I need it to do.

I also wired the remote with standard plugs so when my battery died, I was able to unplug the remote, and plug the relay in directly. Then I was able to keep working by switching the relay directly with my switch.

I know this is kind of off topic a bit, but I thought maybe it would give you some ideas.

[Scott T Smith]

I have ammeters installed on the incoming power in my shop (part of a transfer switch), and it is interesting to watch them as equipment is switched on.

My 3 hp Oneida with a Baldor motor will push the ammeters past 60 amps, for around 2 - 3 seconds.

As stated by the other posters, your problem may be that your fuses are not rated for a long enought time delay.

The dust collector seems to require a longer start up current surge; I presume that it spins up slower than the other equipment due to the mass of the impellor.

[Jeff Bratt]

Looking at Jeff's data, I read the time/current curve as blowing a 30amp fuse at about 1 sec and 125 amps. I wouldn't be surprised at 125 amp inrush on that motor (appx. 6 x FLA). I'm not going out to the shop at 3 a.m. to time the startup of my cyclone, but memory is telling me the spinup time is appreciably more than a second before the centrifugal switch on the start cap opens. (It's spinning one of the ClearVue 16" impellers)

The locked rotor current for these 5HP motors (can't link directly to the Leeson site) is speced at over 150A... so I'll concur with Tom that the 30A fuses are inadequate.

[Rod Sheridan]

The locked rotor current for these 5HP motors (can't link directly to the Leeson site) is speced at over 150A... so I'll concur with Tom that the 30A fuses are inadequate.

The ampere rating of the fuses is adequate, however as Tom stated you need a fuse with a different time/current characteristic.

Regards, Rod.

[Leigh Betsch]

This motor doesn't use a neutral,

I'm assuming that you have the motor on a remote, and that's why you're concerned about having to kill power (i.e. no hard switch?).

You got it. The Clear Vue comes with a 220 relay with a 110 coil. I already had 10/2 + G cable (doesn't have a neutral) and I didn't want to pull 80 ft of new 10/3 cable. I also wanted the relay to power off the same circuit as the motor instead of using a separate 110 circuit so I added a 220 to 110 transformer off the same 220 circuit s the motor so I could power a 110 remote to turn the motor on and off thru the relay. Since the only way turn the motor off was the remote and since the circuit breaker is 80 ft away in another room I added a safety switch to kill the power if needed. I guess my problem is that I used a fused safety switch and undersized fuses. So I guess my solution should be to install a non-fused switch or a switch with time delay cartridge fuses capable of 250 volts. I think I should also put a switch in the 110 remote circuit so I can start and stop the unit if the remote battery dies.
I'll rewire to by pass the safety switch tonight (still on a dedicated circuit with a 30 amp breaker) to just make sure there isn't some other issue and then replace the fused safety switch with another this weekend.

[Jeff Bratt]

Either ditch the fuses completely, or got a disconnect switch that can use cartridge fuses - there are a lot more choices. I don't think the screw base kind even come with 250V ratings. Something like this (http://www.cooperbussmann.com/pdf/747f21a7-7fb4-4a9f-ab8b-ea85d14cc06c.PDF) will work if you decide you still need a fuse - the current rating for a 30A fuse is 200A for 1 sec and about 160A for 10 sec. The spec sheet recommends 130% of motor FLA - so a 25A fuse of this type might be the best choice...

[Roger Frazee]

This fused disconnect is not correct nor is the fuse. It's a 125 volt fuse.

For overcurrent protection always follow manufacturers instructions first if that is not stated with the equipment then follow the NEC requirements which I will breifly outline for this motor.

Going to the manufacturers website for details shows a 30 amp time delay dual element fuse rated 240 volts as the minimum fuse allowed or a inverse time breaker of the same voltage and amperage. This should be fine to get this motor to run without opening a fuse or breaker. The manufacturer does not state a disconnect rating but a 30 amp disconnect is likely to be adequate since the breaker can be 30 amps and is considered to satisfy the required disconnect as far as the NEC is conserned..

If this is not available information then follow the NEC.

His disconnect rating also comes into play. If a single motor on a individual branch circuit the disconnect rating assuming manual overload protection (this motor has that) cannot be less than 115 % of FLC in 430.248. That is 32.2 amps and the next size up disconnect is required which would be what Rollie said a 60 amp 240 volt rated disconnect fusible or non fusible provided the inverse time breaker in the breaker panel is correct. If the disconnect is horsepower rated it simply needs to be a 5hp disconnect for a single motor..which will meet both requiements of 115% of FLC and of course horse power.


#10 copper at approx. 80 feet distance to the tool the locked rotor current during starting will have a instantaneous voltage drop of around 14 to 15 volts. So your getting borderline for voltage required vs rated motor voltage 230 volts to get over the LRA to breakdown torque of this motor. But IMO #10 should be adequate #8 would have been better.

Personally I would not use a fused disconnect on this motor since it has manual overload protection. And the manufacturer states fuse or breaker is fine. If I used a fused disconnect along with a circuit breaker in the panel it would be a 5 hp rated fused disconnect with 35 amp Dual Element FRN class RK 250 volt fuses in each ungrounded conductor. Which is what Rollie is saying.

If I used a non fused disconnect I would use something simple and inexpensive like a 240 volt Square d QO200tr about 12 dollars at the big box or a QO 200TRnm about 15 dollars. If the breaker in the panel is not tripping it likely is fine...you could increase breakers one standard size up to 70 amps (yeah I know this seems wrong but it is not) for this motor on 10AWG copper if it is tripping. The manufacturer states a 30 amp inverse time breaker is adequate not considering large voltage drops. The image is not a fused disconnect though it looks like a circuit breaker.

To say a bit about the max. breaker of 70 amps if following the NEC calculations...this is rarely ever required in applications that are not industrial in nature. A single phase motor like we have here will likely hold start up inrush currents way below the max breaker or max fuse which is why the manufacturer states minimum 30 amp breaker or fuse.

http://ecatalog.squared.com/pubs/Electrical%20Distribution/Load%20Centers/Air%20Conditioning%20Disconnects/QO/60%20A%20240%20Vac%20Non-Fusible%20Molded%20Case%20Switch_lres.jpg

BTW this is the DC motor that Bill Penz uses.


Now to give something to increase ones knowledge of 'fuseology' read this link carefully and apply the chart on page 23 and you will never go wrong on fuse selection. Just remember the fuse voltage rating must be right for the branch circuit your going to protect and never go over 175% of the motor FLC in the NEC table. The general rule I use with a motor like this is to start with one size up from the minimum fuse which in this case is 30 amps so I would start with a 35. In 99.9% of all applications like this that is going to hold the inrush current assuming I have the right dual element time delay fuse. Never exceed the maximum fuse rating.

http://www.bussmann.com/library/docs/spd02/SPDSection03.pdf

[Jim O'Dell]

I've got the Clear Vue wired through a contactor direct to a 30 amp breaker and have never had a problem. Could be that a breaker has a longer delay than the fuse that's being used does. My first question is, was this disconnect something that you had around not being used? I can't imagine finding anything that uses fuses in the stores these days. If it was replaced with one with a breaker in it like A/C unit disconnect has, I bet it would be fine.
Next question: Does it only blow the fuse when you start the cyclone and have one or more blast gates open? And not blow fuses when all of the blast gates are closed? You might watch and see if this is true. If so, the extra power required with the gate(s) open may be just enough to go over the ability of the fuse to handle the start up power requirements. Just a thought. Jim.

[Leigh Betsch]

Thanks for all the help. I was surprised when I got the switch home from Menard's and found out it uses plug fuses instead of cartridge fuses. The box it came in didn't say anything about the type of fuses it takes. I plan to return it and get a cartridge 60 amp switch if I can find the original box it came in.

[Von Bickley]

I would go for the non-fused disconnect.:)

[Alan Schaffter]

One additional thing not mentioned. I don't know if you were doing this, but disconnects are typically not intended to be used as switches. Their contacts are not rated for such. Opening and closing the circuit should only be done when the equipment to be disconnected is not running. The only exception would if you need to disconnect the equipment in an emergency. Same goes for circuit breakers.

[Leigh Betsch]

I pulled the safety switch out and the unit starts up just fine, doesn't trip the 30amp breaker. I did notice that the motor smelled hot and one of the capacitors was very hot, but only one the other was cool. Maybe it's because I started and stopped it about a dozen times in 30 minutes. I flipped the breaker off and figure I'll let it set and try it again tomorrow being a bit less abusive. I've read here that some manufacture don't recommend that much starting and stopping.

[Tom Veatch]

... I've read here that some manufacture don't recommend that much starting and stopping.

Typical manufacturer recommendation is to not exceed 6 start/stop cycles per hour.

If you are going with a 60 amp fused disconnect, I really don't see any point in having the fuses at all. The 30 amp circuit breaker will trip long before a 60 amp slow blow cartridge fuse blows.

[Jeff Bratt]

Thanks for all the help. I was surprised when I got the switch home from Menard's and found out it uses plug fuses instead of cartridge fuses. The box it came in didn't say anything about the type of fuses it takes. I plan to return it and get a cartridge 60 amp switch if I can find the original box it came in.

Why would you need a 60A switch on a 30A circuit? If the fuses are rated any higher than 25 or 30A - they will be doing nothing. A 30A breaker mounted in the shop will work just as well. And if you really want backup overload protection for the motor - have you considered something like this (http://www.schneider-electric.us/products-services/products/circuit-breakers/motor-circuit-protectors/powerpact-electronic-motor-circuit-protectors/), which can be set to the characteristics of motor you are protecting. I don't know what those things cost though...

[Roger Frazee]

Why would you need a 60A switch on a 30A circuit? If the fuses are rated any higher than 25 or 30A - they will be doing nothing. A 30A breaker mounted in the shop will work just as well. And if you really want backup overload protection for the motor - have you considered something like this (http://www.schneider-electric.us/products-services/products/circuit-breakers/motor-circuit-protectors/powerpact-electronic-motor-circuit-protectors/), which can be set to the characteristics of motor you are protecting. I don't know what those things cost though...

Oh somewhere around 1000 to 1300 dollars........:) from squared d ....if not from square d but a wholesaler around 500 bucks.....

Jeff

I agree that it is pointless to use a fused disconnect for this dust collector....but...

As you well know fuses must hold for motor start up. It is true that a 30 amp fuse will likely be fine with this motor but you don't pick the fuse strictly according to the branch circuit rating you are allowed to upsize if necessary. This motor is rated fla of 20.8. that is not how you choose the fuse for overcurrent protection of the motor. The manufacturer will generally state the minimum fuse size if this motor comes with a listed assembly with operators manual but if just the motor comes in a box no such information will be with it. Clearvue says 30 amp fuse as does leeson for this DC system. So that certainly is a good starting point and any further increase in fuse size would be unlikely. Otherwise you follow the nec using the table values for single phase motors.

The simple fact here is unless the manufacturer specifies fuses for overcurrent protection or a fused disconnect for overload protection then a protective device used as the disconnect is not necessary and is pointless to use.

However if you are hell bent to put a fuse in your disconnect even with a circuit breaker upstream and overload at the motor in manual reset form then you want a fuse that will hold and not open during start up. A fuse is not a breaker so I was simply stating earlier that I would use a 35 amp fuse so that it would hold with a good degree of certainty without going crazy with fuses way over the minimum or up to the maximum overcurrent rating of 50 amps. After all and as you are pointing out I have ocpd at the panel in the form of an inverse time circuit breaker.

If I was using a fuse for ocpd which is common when running feeders serving a group of motors and this motor was one in that group I would fuse it with 35 amps. And remember overcurrent rating of a fuse is not calculated the same as overload rating of a fuse.

As Alan correctly pointed out disconnects are not intended to be used as on and off switches. However disconnects can be motor controllers...:) depends on what your using.

What I mean to say is you can have an on-off switch that can be suitable for a disconnect. If you want some thing on the wall that is the motor controller and disconnect to turn off and on the machine then the best method for most applications like we are talking about here could be satisfied with one these (link below) which are rated 30 amps. The reason this complies as a disconnect rated less than 60 amps for this motor is due to an exception in 430.110 (A) where a listed motor switch rated equal in hp to the motor can be rated less in amps than 115% of the flc of the motor. Personally I agree with you that a 30 amp rated disconnect of any kind is fine for this motor. But if Leigh wants to use the disconnect to control the motor he can not use a disconnect that is not rated as a controller.

http://www.hubbellonline.com/wiring/datasheets/H2170.PDF

The reason a 60 amp disconnect is required (according to the NEC) and not using the motor switch exception is because this is a 5 hp motor not part of a listed motor appliance and you must use the table flc of the nec to size the disconnect. With table flc of 28 amps the calculation comes out an amperage of 32.2 amps so you would move to the next size up disconnect rating which is 60 amps because the disconnect must not be less than 115% of the table FLC of 28 amps. The motor hp is 5 so a 5 hp disconnect based on locked rotor table value of 168 amps will not work because it is rated 28 amps as an equivalent hp FLC.

So you either have to have a disconnect rated more than 5 hp or a 60 amp rated disconnect.

A disconnect is not rated as a on-off switch but a controller can be rated as a disconnect. A disconnect is meant to be for short interruptions usually not under load for servicing of the motor. However they must be rated to open locked rotor current in the event of an emergency so disconnects have a wide gap between contacts.

I wish I could tell you why you have to use the FLC of the NEC tables for overcurrent and branch circuit sizing etc...because the values are quite a bit higher in most cases than nameplace flc or fla but that's how it is so you follow the rules like it or not.

Now if the motor is part of a listed motor appliaince that the nameplate lists both hp and fla then you may use the nameplate fla to size the conductors, overload, ocpd and disconnect. If we could do this with this motor then a 30 amp disconnect may be fine.


NEC 430.109 specifies the types of devices that can be disconnects for a motor. In this situation with this dust collector the circuit breaker is the most obvious device that is rated as a disconnect. If the distance is great to the circuit breaker I might want a disconnect closer to the motor which is what I understood that Leigh wants. I do not know why he wants to fuse it.

There is no need for a fused disconnect close to the motor.... this motor has manual overload protection and a breaker for ocpd and serves as the disconnect.

If Leigh wants a maintenance disconnect close to the DC motor... and.. it really is not a bad idea.. I would do so... I just wouldn't fuse it.

[John Coloccia]

Again, this is why I simply put a switch on the relay instead. For maintenance, I unplug the cord from the wall. Gives me warm fuzzies to see the plug as opposed to remembering if I flipped a breaker.

[Alan Schaffter]

Again, this is why I simply put a switch on the relay instead. For maintenance, I unplug the cord from the wall. Gives me warm fuzzies to see the plug as opposed to remembering if I flipped a breaker.

That works if the relay is collocated with the DC. My relay isn't, so I put a manual disconnect adjacent to the blower and always pull it when I inspect or do maintenance. It gives me visual confirmation the DC control is not powered and will absolutely not start. For that reason most HVAC and similar outside equipment require a disconnect.

[John Coloccia]

Interesting. Why is the relay not near the DC? I'm not trying to second guess you at all. I'm really just curious about you're installation and maybe get some ideas for future installs.

[Alan Schaffter]

Interesting. Why is the relay not near the DC? I'm not trying to second guess you at all. I'm really just curious about you're installation and maybe get some ideas for future installs.

My subpanel is at shop level (second story shop). I control my DC with a 24V 3-wire LVC system. My cyclone is down below at garage level.

Here is a pic taken before I installed wallboard of one control station (I have 6). The enclosure to its right houses the 24V transformer and a 30A contactor. Just to the right of that, but not visible, is my shop's 100A sub panel. It was much easier running the LVC circuit with the contactor at shop level.

http://www.ncwoodworker.net/pp/data/1329/medium/P10100522.JPG

My cyclone is mounted high on a wall in a room off the garage. The (yellow) power cable runs down the right edge of the right 2x4 to a disconnect mounted on the wall at a convenient height (hidden by the compressor in this pic):

http://www.ncwoodworker.net/pp/data/1329/medium/P10100382.JPG

[Jeff Bratt]

Roger - when quoting the NEC, the explanations can sure get long-winded. I guess the NEC table of FLC values for 5 HP motors covers even the most inefficient motor designs - even though the nameplate FLC of this motor is 20.8 amps... Since the motor nameplate details the FLC and HP, would anything more be needed to qualify it as a "listed appliance"? Also, wouldn't the same 30 breaker that is in the remote panel work here also?

From the link you supplied, it looks like the Hubbell "motor controller" switch (or something equivalent), 30A @ 240V is rated for use with 5 HP motors, and would be perfect for this application. And get rid of the fuses altogether...

Thanks for your detailed explanations.

[Alan Schaffter]

Not sure the specifics of how NEC lists this stuff, but remember a 30A device ("appliance") is not always a 30A device. Resistive loads (stoves, baseboard heaters, etc.) are treated differently than reactive or inductive loads (motors).

[Tom Godley]

Alan -- That looks like a nice control.

Where did you purchase?

[Roger Frazee]

Jeff

I must apologize for my long winded replies and yes the NEC makes things more complicated than meets the eye. But there just isn't an easy way to explain things looking at this motor from an electricians stand point. I will try to keep things as simple as possible but you guys here are not dummies and I find it better to get into the details because I feel many of the members here do not have a problem understanding details...I think it is inherit in the wood working trade .... :) You know determining what is an appliance gets sorta controversal but the way I look at it is if the motor comes permanently attached to the machine as an assembled unit...its an appliance if the motor doesn't get to big. Table saws are probably appliances except essentially all you have is a motor driving a blade there generally is no timer or cycle operated pumps or that nature going on as an assembled unit like a dishwasher.. In other words you don't do anything but plug it or wire the factory pigtail in and go. And a set of instructions gives you all the details about the conductor size and the circuit breaker to determine the branch circuit rating. If you have to mount a motor to a DC and essentially power that motor by wiring directly to it IMO it is a motor circuit and fall under the motor rules of the NEC. A listed motor appliance is the key.. the word listed simply means that a testing lab like UL has tested the appliance and the nameplate is more accurate than the NEC tables. Sorta odd in my opinion but not all listed motors have both hp and fla on the nameplate sooooo..what do you do? I think in most cases that are not 3 phase industrial motor application you likely will be fine using nameplate data. That's one of the problems with the nec... they try to cover all applications and it gets tough sometimes to determine what their intent was in the language they use.

Yes the breaker works the same in this situation also to answer your question.

Now we should thank Alan because he brought up the point that Leigh was or at least appeared to be misusing a 'disconnect' as a on/off switch for the DC. You don't want to do that as his device was not a controller listed device. If he wants that I would get the motor switch I linked to and get the cover you see in the image that allows you to pad lock the switch in the open position or a pull out disconnect like Alan is using. I suspect Alan is using a 60 amp a/c disconnect with pull out provision. The other disconnect that I posted QO200trnm is also a 60 amp disconnect primarily for an a/c condenser compressor and can be locked out with a pad lock on the cover. But it is not a controller rated disconnect. So I think we have beat that horse enough.....:)

Anyway I'm glad Alan brought up the obvious as I missed it entirely. Mostly because I was trying to be too detailed probably and took it for granted that the word disconnect would be understood by everyone to be just that .. a way to disconnect power to the motor for servicing.

BTW ALAN ... in looking at your stop/start station where your contacter is located I noticed you have a major goof ... your insulation is upside down :eek:

See there I go again with long winded replies.

Thanks for not being to harsh on me here I'm pretty new to this forum but hopefully I get to learn something and maybe someone else, by some miracle, will learn from my long windedness....I think that's a word..:)

Roger

[Leigh Betsch]

Just to clarify. I'm not intending to use the disconnect as an on off switch, that's what I have the relay and remote for. I do intend to use the disconnect as a method to kill the power for maintenance and inspection or in case of an emergency when I might not have time to run 80 feet through 2 rooms to the main panel. Kind of hard for me to follow all the details but I'll be on my way to the BORG tonight to by an "un-fused" 60 amp disconnect. I'll ditch the extra fuses as a bad idea but I still would like to have the ability to kill the power quickly if needed.

[Roger Frazee]

Hi Leigh

Yeah we got a little carried away didn't we. Thanks for the clarification..even though I see in your first post you were quite clear how you were using the disconnect and just a few posts later told us it came with relay and remote.... :o Sometimes I have a short memory... But look what we learned..... :D So it sounds like you have this figured out even though we tried our best to keep that from happening....:) I'm not sure how things work but it would be possible and you choose to open the disconnect to turn the motor off that your contactor will stay closed so just something to think about. This probably depends where in the circuit the disonnect is located.


I just read though where you say your motor is hot? I would assume it is from fast cycling of the motor. If it continues to get hot without frequent on and off cycles let us know.

[Alan Schaffter]

Alan -- That looks like a nice control.

Where did you purchase?

These are surplus (Delta) button/covers I got on Ebay a few years ago (there are some for sale there now) (http://cgi.ebay.com/4-New-Delta-Rockwell-push-button-power-switch-covers_W0QQitemZ320459422091QQcmdZViewItemQQptZLH_ DefaultDomain_0?hash=item4a9cdeb98b). They push on small momentary buttons (1 normally open- start, 1 normally closed- stop) (like these (http://cgi.ebay.com/8-SPDT-Momentary-Red-Push-Button-Switch-250V-2A-120V-5A_W0QQitemZ390129180068QQcmdZViewItemQQptZLH_Defa ultDomain_0?hash=item5ad582dda4)) I got at Radio Shack and mounted to a little bracket. The switches were nothing special since they just control 24V.

[Alan Schaffter]

Just to clarify. I'm not intending to use the disconnect as an on off switch, that's what I have the relay and remote for. I do intend to use the disconnect as a method to kill the power for maintenance and inspection or in case of an emergency when I might not have time to run 80 feet through 2 rooms to the main panel. Kind of hard for me to follow all the details but I'll be on my way to the BORG tonight to by an "un-fused" 60 amp disconnect. I'll ditch the extra fuses as a bad idea but I still would like to have the ability to kill the power quickly if needed.


In addition to making sure no one powers up the equipment while you are working on it and another reason for a disconnect (actually required in many cases) is that it gives you another way in addition to the breaker, to turn the equipment off if the relay contacts fuse and your remote will not shut it off- not an unusual occurrence since relay contacts can weld closed very easily. In the case of HVAC and other types of equip- the disconnect must be with in a certain distance/visual range from the equipment.

[Leigh Betsch]

I bought a Square D QO200TR 60 amp "un-fused" disconnect switch at the BORG tonight and plan to install it in replace of my 30 amp fused one. It will be about 4ft from the dust collector, well with in sight. My DC is in a room that adjoins my shop but it doesn't have a door directly into the shop, I definitely wanted the switch in the same room as the DC in case of an emergency.
Now I need to go back and re-read the post about how to add an additional switch into the control circuit in case my remote's battery fails. This seams like a reall possibility.
I would like to mount this switch inside the shop.

And thanks for all the help!

[John Coloccia]

I bought a Square D QO200TR 60 amp "un-fused" disconnect switch at the BORG tonight and plan to install it in replace of my 30 amp fused one. It will be about 4ft from the dust collector, well with in sight. My DC is in a room that adjoins my shop but it doesn't have a door directly into the shop, I definitely wanted the switch in the same room as the DC in case of an emergency.
Now I need to go back and re-read the post about how to add an additional switch into the control circuit in case my remote's battery fails. This seams like a reall possibility.
I would like to mount this switch inside the shop.

And thanks for all the help!

On mine, I used a combination switch/15A fuse that I found at Home Depot. It's a tiny little thing that I mounted right on the side of my relay box. I added this additional fuse because I used the 30A circuit and a neutral to drive the remote. The remote is designed to plug into a 15A....maybe 20A...circuit. Who knows how long it'd last if it actually saw a 30A short. If your remote is already on a separate 15A circuit, the fuse is superfluous and you only need the switch.

So the Hot goes to the switch/fuse. Coming out of the switch is a power cord with a female plug (just like an extension cord). So at this point, I essentially have a switched 120V outlet.

The relay is setup the same way except with the male connector (just like any other piece of equipment).

The remote is designed like a power strip. You plug one end into the wall, and plug the decide you're controlling into the other end. So I plug the remote into the plug coming off the switch, and the relay plug goes into the remote. Now the trick is that I made all cords long enough that if I want to, I can unplug the remote completely, and plug the relay directly into the switch, and voila' - the remote is bypassed but everything still works.

Once I realized that I had to put 120V style plugs on everything because that's what the remote wanted, it was a no brainer to do an extra 20 minutes worth of work to add a switch for the inevitable "Where the heck is the $%@# remote" moments.

[Leigh Betsch]

Thanks John for the info on how to get the switch and remote wired up. But it looks like I have bigger problems than I thought.
I installed the 60 amp non-fused switch tonight but when I went to give it a try the motor just hummed. I quickly powered down. I pulled the cover off the motor box and I found a wire nut burned thru and a feed wire with the insulation charred. I pulled the capacitor cover off because last night I knew one of the capacitors was hot. Sure enough the top of the capacitor was burned thru and the oil leaked out. Looks like I had a small fire in it last night. I was thinking something else might be wrong because someone said that their motor would spin up to speed in a couple of seconds but mine would take 7 - 8 seconds to spin up. So I'm thinking that the original problem with the fuses blowing had more to do with an actual motor problem than the undersized fuses. Thru all of this neither the 30 amp circuit breaker or the motor overload ever tripped. I can spin the fan easily by hand so I don't think there is anything keeping the motor from turning. I'll call Ed at Clearview tomorrow and see if he has any ideas on how to troubleshoot the problem further. I'm pretty leery of using the motor even if I get a new capacitor.

[Alan Schaffter]

A couple of problems come to mind immediately since the motor worked, sort of:

Start capacitor is bad (motor may or may not start, if it does it will usually hum and come up to speed very slowly and usually trip the breaker either way)

Centrifugal switch is bad (bad contacts or bad spring). Can cause the same symptoms as above if doesn't switch to start mode or it can get stuck in the start mode and will usually trip the breaker when up to speed.
There could be other problems with the motor wiring, but the above two are the most common

[Leigh Betsch]

So is there a way to investigate why the capacitor burned up without pulling the motor? I can get at the motor from above real easily to wire or replace the capacitors but if I have to pull the motor I'll have to pull the whole cyclone down since the motor is attached to the fan and it must come out from the bottom.

[Alan Schaffter]

So is there a way to investigate why the capacitor burned up without pulling the motor? I can get at the motor from above real easily to wire or replace the capacitors but if I have to pull the motor I'll have to pull the whole cyclone down since the motor is attached to the fan and it must come out from the bottom.

The centrifugal switch is inside the end of the motor fan housing. The capacitor wires into that area also. If you can get above the motor, you should be able to remove the housing and inspect the centrifugal switch. Time to hit Google so you know what you are looking at and what to look for. You will want to check all the wiring- all the wires should be color coded or have a number on a band or printed right on the insulation. If this is a new unit with a new Leeson still under warranty, I would consider a replacement. Once you tear into it, it is probably yours.

[Leigh Betsch]

Once you tear into it, it is probably yours.

Yeah. I'm going to give Ed a call tomorrow. I really don't want to remove the motor but it would probably be best just to replace it if I can get it under warrenty. Even if it isn't covered under warenty I would feel better if I had a motor shop fix it.

[Roger Frazee]

Crap...I was worried you might have something else going on when you said how hot it was getting.

Alan thought of a couple reasons. Did you make the connections to the motor?

This is what the motor looks like cosmetically
http://www.electricmotorwarehouse.com/IMAGES/120554C.gif
It is a capacitor start capacitor run. If the motor is taking a long time to come up to speed the start capacitor will fail and burn through. So I suspect the burned capacitor is the start one. This motor should under normal conditions accelerate to speed in about 3 seconds.

One of the things that can cause this is as Alan said a stuck start switch inside the motor and the start winding is not being taken out of the circuit when the motor reaches a certain rpm.

The other is too low of voltage. If the voltage is was way low say 15 or 20 % below 230 volts it might cause this problem but I don't think that is it at your distance

Now there is one more thing and I hate to bring this up but rapid cycling of the motor can cause what you are seeing and it happens to the start capacitor not the run capacitor. In general you should not have more than 15 to 20 .... 3 to 5 second starts per hour. I'm not sure what it is per minute but I'm worried this may be what happened. As for the breaker or the overload not tripping that is difficult to say at this point.


I'm sorry to hear this ...:(...

[Leigh Betsch]

Yeah if it's the multiple start thing I could have caused it. If so would just replacing the start capacitor fix it or would there be other damage? If I end up biting the cost of a $350 motor I'll just have to suck it up.

[Roger Frazee]

Boy Leigh that's a tough call. Replacing the capacitor is no big deal and not very expensive. I'd give it a try what have you got to lose?? The fuses really were not undersized but the wrong voltage rating so I would expect them to open every now and then.

I think you said that the motor was always slow to accelerate from day one? If so this puts another wrench into things. You may be real low on voltage at the motor but if it is only 80 feet I'm just not seeing that as an issue with 10 AWG.

I'd throw another capacitor in it but make sure it is the right one. On a start capacitor there are things you can do with the start capacitor if you have a need to cycle a lot (doesn't sound like you do) and that is you can go up in voltage rating of the capacitor as long as it is the start capacitor an install a 'bleed resistor. But frankly you should not have to do this. This is usually done on conveyor systems where the motors are starting frequently.
Heres a link to a good motor branch circuit load calculator and other calculators for voltage drop etc....

http://www.electrician2.com/calculators/motor_ver_1.html


when I run your figures thru the motor calculator they come out real good with 10 awg.
So if you have a voltage problem it may be at the supply or the remote control contactor it's just hard to say.

[Roger Frazee]

Before I call it a night I just wanted to add that low voltage will cause inrush current to go down at start up so this may be partly to blame for the circuit breaker holding. BUT you should not be having low voltage problems so just look your connections over good thru the whole wiring circuit.

I've been looking for a motor book on leeson motors that I have and finally located the darn thing. Didn't get much out of it but did give me a link location for the factory troubleshooting chart for their motors so thought I would just post it for your and others reference.

TROUBL~1.PDF (application/pdf Object) (http://www.electricmotorwarehouse.com/PDF/TROUBL%7E1.PDF)

[Tom Veatch]

Yeah. I'm going to give Ed a call tomorrow. I really don't want to remove the motor but it would probably be best just to replace it if I can get it under warrenty. Even if it isn't covered under warenty I would feel better if I had a motor shop fix it.

Leigh, of course you have to do what's right for you. Swapping out a start cap is a pretty trivial task. Dismounting that motor from the top of a cyclone is a royal PITA. To me, it would be well worth the $10 or so for a new start cap, if that meant I had a reasonable shot at not having to dismount the motor.

In a previous post, you mentioned numerous motor startups in a short period of time. If I were going to guess, that's where I'd put the blame. Very likely you overheated the capacitor and let the magic smoke out. But it's also possible the centrifugal switch went south which would also kill the start capacitor.

[Alan Schaffter]

Time to dig out the step ladder.

[Roger Frazee]

Time to dig out the step ladder.

There's always a pessimist in the crowd.....:)

[John Coloccia]

I'm more interested in the wire nut that's burned through. Okay, sure it may have happened when the cap died, but I think there's a decent chance you had a poor connection there to begin with. A high impedance connection would explain the slow startup performance, and would also explain why the wire nut/wires are charred.

Personally, I'd replace the cap, check and redo all the connections in the motor box, and go from there. If the performance is still poor, it might be time to get a friend who knows what he's doing and start probing around to see where it's going wrong.

[Jim O'Dell]

You also mentioned something about some charred wiring. Make sure you get that taken care of also.

As a side note to redoing all your connections. I second that. I was this close ( finger and thumb about 1/8" apart) from starting my CV for the first time when a little voice said to go back through the wiring at the motor first. Glad I did. I found a wire missing that was shown in the schematic. I finally found it....under the wiring housing grounded to the frame of the motor. Came that way from the factory. Don't know what would have happened if I had turned it on that way, but I'm sure it would not have been pretty. Now I don't think that is your troubles, but just make sure you have all the wires identified and in the proper place! Jim.

[Roger Frazee]

I have to agree with John that this whole thing sounds like one of those obscure wiring connections that was bad that went unnoticed. Your breaker never sees this sort of connection and will not trip. Unfortunately it is hard to troubleshoot over the internet. I can walk you through ohming out the windings in case there is damage there but bottom line is if you repair the burned wiring and replace the capacitor it's either going to start correctly or not and if a winding burned through your SOL.

Sounds like the motor got awfully hot also but maybe not that part of the motor that would trip the overload. I think it is a bad connection coupled with the fast cycling that caused the failure. The motor windings likely never got hot enough to trip the overload. The breaker should have opened if the current stayed up around locked rotor amps that long. What size is it...? A double 30 is probably what you have. It didn't so this lends more favor to Johns suspicion of a bad connection in a wirenut..

With your new disconnect so close to the motor I would recommend when you rewire or change out the motor to run stranded from the disconnect to the motor in armored flex conduit or what some call a whip motor connection.. You can get this with the stranded wires already in it or put your own thhn stranded into the flex. You just need a couple box flex connectors for the disconnect and motor. This will give you stranded only in the wiring peckerhead of the motor and will improve your terminations there if using wirenuts. Ideal 'twisters' or buchanon B-Caps in my opinion are the best wirenuts on the market. The GB Hex-loc is highly recommended by many electricians.

The wiring diagram as you know is on the motor namplate or on the wiring peckerhead cover.

So when you rewire be sure you have P1 connected to line (L1). That is all that will be connected to that line wire for a straight 230 volt motor like you have. This puts the manual thermal overload into the circuit. I'm not sure if the motor can be wired for 2 rotation directions (CW and CCW) so it has to be wired for the correct rotation. I can tell you the rest of the connections if you want to verify them. But as John said it is highly likely if the connections were correct to begin with... and I would say they were.. other than possibly rotation.. otherwise the motor would have smoked at the git go... you probably had a loose connection at the wire nut as John thinks and the fast cycling didn't help things.. This is not all that uncommon if you brought solid #10 into the peckerhead of the motor and connected it to stranded in wire nuts. If it was prewired then maybe the factory messed up a connection. Anyway if you are connecting stranded to solid in a wire nut let the standed be about 1/8 to 3/16" longer than than the solid on the stripped ends. You get a better bite in the wire nut that way and it won't ball up inside the wirenut because the wire spring grabs the stranded first and holds it into the top of the wirenut.

After you terminate the wires give them a reasonable tug to make sure they are secure.

Now one more thing usually the motor lead wires are small and very flexible.... connecting 10 solid to them is a PITA. Not telling you what to do but if it were me I'd deviate from the NEC a bit and run #12 thhn solid or stranded to the motor from the disconnect... I will explain. If the manufacturer explicity states #10 then I suppose you will have to do that. You have #10 all the way to the disconnect so assuming good voltage you have just over 1% VD under load at the disconnect location. IMO #12 awg thhn (not romex) will carry all the amperage this motor will ever need. And yes for motors you can have a bigger breaker than 20 amps on #12 thhn wire. The breaker is to hold the inrush at start up.. the wire is to carry the amperage of the load... the motor has overload protection. Your fla is 20.8 amps for this motor. THHN #12 copper has an ampacity of 25 amps sooo..I dont see any issue and your life will be easier at the motor terminations.

Just trying to make sure the next time around you have good connections.

Sorry if I am misunderstanding the termination method at the motor but sounds like wirenuts connecting motor leads to the supply wires.

[Leigh Betsch]

I talked with Ed at Clear Vue today. He's going to send me a new capacitor. He doesn't think that cycling the motor caused the problem. When they balance fans they cycle a motor on and off 15 times in 30 minutes. He also said that he hasn't heard of anyone else having problems due to excessive cycling. He thinks it might just be a bad cap from the git go. I guess I'll give it a whirl and hope it works so I don't have to pull the motor out. I did have it wired with THHN 10 ga solid wire inside a seal tight conduit. I replaced the wire from the relay to and motor with THHN 10ga stranded (just couldn't get my self to use 12ga). L1 to P1; L2 to T4 and T8; T1 T5 and P3 wired together, just like Lesson says for CW rotation. So far it looks like a bad connection or a bad capacitor started this all. Now I just have to wait for the new cap and keep my fingers crossed that the motor is ok.
I think I'll get all my plane blades and chisels sharpened this weekend.

[Roger Frazee]

I hope that is all it turns out to be....keeping my fingers crossed.

NO big deal on the #10 vs #12 I figured it would make you uneasy after what you have been through....:)

Hey just thought I would show you how things are going on with your motor windings and start and run capacitors.

When you look a the drawing below just visualize a centrifugal switch opening the circuit between the t6 and t9 lead at about 80% rated motor speed. this drops out the start circuit and winding and the run winding stays in the circuit. The start winding is still used but at the lower capacitance of the run capacitor.

Drawing came off of the leeson site for your motor and I just drew the connections in...

Thought you would find it of interest.

You have the connections correct by the way .... for clockwise rotation.

I sure hope this has a happy ending ..... :D

[Alan Schaffter]

You have the connections correct by the way .... for clockwise rotation.


Remember, rotation is determined by looking at the shaft end of the motor with the shaft facing you.

[Roger Frazee]

Remember, rotation is determined by looking at the shaft end of the motor with the shaft facing you.

Yes.. good catch .. the drawing is from the switch end . I placed an arrow on the drawing to show the rotation of the shaft.

Also in my hurry to try to make the drawing what I thought would be more simple I placed the centrifugal switch on T8 which took the start winding out of the circuit of the run capacitor. The start winding never really completely deenergizes it just moves from the higher rating of the start capacitor to the lower rating of the run capacitor. This improves the efficiency of the motor.

The drawing has been corrected

Sorry for that skip in my brain

[Leigh Betsch]

If you guys aren't careful I might start to understand this stuff!

[Roger Frazee]

If you guys aren't careful I might start to understand this stuff!

Yeah.. I know.... I'm prone to give more information than is needed but just think you can see how to ohm out your motor now....:)

That's a nice shot of pheasants in your avatar... can't tell what kind of dog you have though....


I traveled to Winner, SD for many years and had some wonderful hunts and great hospitality. We hunted private ground with friends from the area never got into the pay to hunt thing. boy have you guys got a lot of pheasants. I heard it was almost hard to believe back in the 50's. Seem I remember being told you could shoot 7 birds in those days roosters or hens.

[Leigh Betsch]

I really do appreciate all the help and explanations. Electricity is a whole lot more than black to black white to white, it one of the things I need the most help with.
Deutsch Drahthaars. He's may male, born just outside of Berlin. I have two, one male one female.
In the Winner area it's pretty common to see 1000 birds in a day. Not nearly that good around here though. There was a proposal to open the limit to 5 rosters per day in December because not enough birds have been harvested this year. The proposal was turned down though, limit is 3 but that's ok with me. Now the weather has tanked so only the die hard hunters will be out.

[Leigh Betsch]

I installed a new capacitor this morning. The unit fired up once but when I shut it down it kinda ground to a stop and wouldn't go again. I could get the fan to turn by hand but it was never really free. So I pulled the motor out. It really wasn't too bad to get it out since I could get at it from the top. So I figured I'd tear into it. I hated to since it's brand new and covered under warranty but I also tired of breathing dust. I pulled the end cap off and found that the end of one of the springs on the centrifugal switch was broken and the spring was laying inside the end cap. I called the local Leesson repair shop (yes someone was there on a Saturday morning!). He didn't have a spring or a new switch but he said to just make a hook out of the last spring winding and use it. On Monday he will order me a new switch, under warranty. I also found the broken end had wedged under the armature, and put a nice groove in the armature also. I put it all back together and she runs just fine.
So my question is "Is the grooved armature anything to worry about?"
It's just a small groove maybe .04 wide and 3 or 4 inches around the armature. I could pull the motor out again and take it into the repair shop on Monday and see if I could get the motor or armature replaced under warranty. I'm thinking this has been the problem all along with the capacitor and the wire nut burning up. I still don't know why the breaker never tripped though.

[Alan Schaffter]

Looks like problem #2 in my list. :D

Scratch shouldn't be a problem, but without seeing I can't say. Ask the repair shop what they think.

[Roger Frazee]

Looks like Alan gets the cigar and you got the step ladder...:D

I agree though small scratch should be nothing to worry about.


Jeez ... talk about having something goofy happen to your new motor...:mad:

[Leigh Betsch]

I talked to Ed at Clear Vue. He's sending out a new motor. He thinks a 4 second spin up time is too long and there might be something else wrong with the unit. I would have been happy with a new spring but Ed doesn't think it is right. Gotta like service like that.
I made a couple of installation changes and now I can pull the motor out the top in 15 minutes.

[Roger Frazee]

I talked to Ed at Clear Vue. He's sending out a new motor. He thinks a 4 second spin up time is too long and there might be something else wrong with the unit. I would have been happy with a new spring but Ed doesn't think it is right. Gotta like service like that.
I made a couple of installation changes and now I can pull the motor out the top in 15 minutes.

Yep sounds like they are trying to do the right thing....sometimes rare these days.

Be sure to let us know how the new motor works out.