3ph 3 hp PM66- new motor or vfd?

[Patrick Curry]

I picked up a 74’ PM 66 with a 3phase & 3 hp motor model 35A13-863. A new, 3hp single phase baldor motor is $385 plus another $20 or so for the switch (internet prices).
The other consideration is a vfd and I believe Teco runs about $300, plus a switch if needed.
My initial thoughts are that it’s going to be easier swapping out the 3 phase motor for the the single phase plus a new switch.
Thoughts?

[Bill Dufour]

Should not need a new switch either way. May need higher amp heaters (2) if you go single phase and it has a motor starter. If you are lucky they are adjustable heaters.
VFD. no name china one can be had for $120. On the vfd use the existing switch for low voltage control.
Bill D

[Matt Day]

A 3hp tech fm50 costs $200, and a switch can be as simple as a $1 light switch. I have push button e-stop’s in mine which are less than $10 on Amazon.

As bill said, plenty of non name China vfd’s Available for cheaper. Teco has great customer support which might be worth it if you’re not electrically inclined.

[Bill Dufour]

Why do you think you need a new switch? Does it have a switch that you do not like?
Bill

[David Kumm]

I'm a three phase guy but if you go with a single phase motor you will likely need a new starter. I would not put a cheap switch on a tablesaw. It should have a mag starter. The orginal may be a size 0 and a single phase 3 hp motor needs at least a size 1. If the existing is large enough and has adjustable overloads, you won't need to swap anything. A start stop for a vfd costs almost nothing and can be placed anywhere on the machine. Dave

[Mike Henderson]

I'd go with the VFD but that's just me. A single phase motor is the simpler solution.

Mike

[Dan Friedrichs]

You can get a no-name VFD for much cheaper than a new motor. VFD also gives you variable speed - not super useful on a table saw, but maybe if you want to run moulder heads or a sanding disk? VFD also gives you braking - you could have the blade stop much faster than if it's just air friction slowing it down (although you have to be careful to not set the braking too fast or you'll loosen the arbor nut). I'd vote VFD, but I like VFDs :)

[Chris Hachet]

TECO Fm 50 for my 3 phase 3 Horse Delta Unsiaw was something like $196. Three phase motor will cut anything. Very happy.

[Patrick Curry]

<p>
It was my understanding that the vfd switches are small and difficult to position where needed...and rhe exiting switch needs to be removed from the vfd to motor connection.</p>

[Patrick Curry]

Thanks for the information.
The existing switch is fine, but Im under the impression the 220v out of the vfd needs a different switch the the original 3 phase

[Patrick Curry]

Yep. Comfort in familiarity.
I know I can swap motors. But I can&rsquo;t seem to even find the right vfd on eBay, let alone the installation

[Geoff Crimmins]

Thanks for the information.
The existing switch is fine, but Im under the impression the 220v out of the vfd needs a different switch the the original 3 phase

With a VFD there is no switch on the 220v lines. Instead, a switch is wired to two low-voltage control terminals on the VFD, which tells it to turn the motor on or off. You can use almost any on-off switch for this. Some VFDs, such as the Teco FM-50, can also be set up to work with momentary push buttons, such as those used with a magnetic starter.

While it takes a bit of work to figure how to connect and program a VFD, it's probably the least expensive solution. You could also use a static phase converter, but they only power 2 of the 3 legs on the three phase motor, so you don't get the motor's rated HP, and I'm not sure they are great for the motor. If you get a 3hp single-phase motor you'll have to replace the heaters in the starter. It's also possible that the starter is not sized to work with the current from a 3hp single-phase motor, in which case you'll have to get a new starter. One way to avoid changing anything with the starter is to use a smaller 220v single-phase motor that has the same amps rating as the 3hp 3-phase motor. I don't know of the top of my head what that would be, but it might be around a 2hp motor. Actually, that would probably be the simplest solution, and could be cheaper than a VFD if you find a good deal on a motor.

[Patrick Curry]

<p>
If I purchased a 3hp single phase replacement motor I would need a new starter? That&rsquo;s news to me- also shatters the small yet misguided confidence that lead me to this. I thought the starter and all the other goodies of a motor were inside the casing? I don&rsquo;t want to lose any power so static phase converters are out. $385 for a new Baldor single phase 3hp was palatable, and I initially thought it would be easier than wiring a VFD. But adding a starter might push this out of play. I don&rsquo;t know...guess I&rsquo;m back to a vfd. Also, I meant to say that I thought a new switch was necessary if I replaced the mtir with a single phase. It was my understanding that the 3 phase starter switch would not work, and the switch On a vfd if I went that route, would be too small and likely out if reach</p>

[Patrick Curry]

TECO Fm 50 for my 3 phase 3 Horse Delta Unsiaw was something like $196. Three phase motor will cut anything. Very happy.
I must be looking at the wrong models. The Teco I spec&rsquo;d out was $320.

[Patrick Curry]

Amp heaters? Can you elaborate? I was under the impression a new 3hp motor would be somewhat self sufficient after mounting and adding a switch

[David Kumm]

Patrick, you need to do a lot more homework before wiring up a machine. A three phase motor of equal hp uses a little more than half of the amperage of its single phase replacement. therefore you may need to replace the starter with one of larger size. See my earlier post. Because the amperage doubles, you will also need to size the overloads ( heaters ) in the starter for the new motor. I'm also assuming that the new motor is the same frame size and has the same length shaft so the pulleys ( sheaves ) will fit and the belts won't need to be swapped. Dave

[Andrew Seemann]

Replacing the motor with a single phase motor and putting a new starter on will probably cost you more than a VFD, but at the same time, you will never need to think about it again or replace it in your life. Not sure if you can say the same about a VFD off eBay. Just something to think about.

[Patrick Curry]

<p>

Patrick, you need to do a lot more homework before wiring up a machine. A three phase motor of equal hp uses a little more than half of the amperage of its single phase replacement. therefore you may need to replace the starter with one of larger size. See my earlier post. Because the amperage doubles, you will also need to size the overloads ( heaters ) in the starter for the new motor. I&#39;m also assuming that the new motor is the same frame size and has the same length shaft so the pulleys ( sheaves ) will fit and the belts won&#39;t need to be swapped. Dave A starter as in a motor switch, correct? &nbsp;I was counting on a replacement switch or starter to match the higher amperage of the single phase. $25 or so.</p>

[Matt Day]

Dave means a starter, not just a “switch”. By starter that means magnetic starter - the benefit is that if the power shuts off while cutting, it won’t turn right back on when the power comes back on. Magnetic starters for 3hp will cost about $100+.

http://www.grizzly.com/products/Magnetic-Switch-Single-Phase-220V-Only-3HP-21-25A/T24101

[Dan Friedrichs]

Patrick, are you typing your replies in some other program, then copy/pasting them into the text box on this site? Your posts contain formatting characters because of that.

[Patrick Curry]

Patrick, are you typing your replies in some other program, then copy/pasting them into the text box on this site? Your posts contain formatting characters because of that.

Dan, I was typing my replies through an IPad which for some reason doesn't play well with this website. Very annoying. Commas, apostrophes and other non-alpha characters are converted into those strange symbols, and then also my replies were not attached to the post I was responding to. I'm on my desktop now.

[Geoff Crimmins]

Magnetic starters for motors are designed to work with several sizes of motors, with the interchangeable heaters (overloads) sized to the amp-rating of the specific motor it's being used with. There are several sizes of starters (00, 0, 1, 2, etc.) that each work with a certain range of motors. It may be that that the starter on your saw is sized to work with both 1-phase and 3-phase 3hp motors, in which case you'll only need to change the heaters, which isn't especially expensive or difficult. Or it may be that the starter on your saw is sized to work with the 3-phase 3 hp motor, but is too small for use with a single-phase 3hp motor, in which case you'll need to replace the starter (or use a smaller motor.) With the saw unplugged you can remove the cover from the starter on the saw. Inside the cover there should be a chart of heaters that will work with the starter. Check the amp rating on the single phase motor, and see if that number appears on the chart of heaters. If it does, then you just need new heaters. If you're comfortable doing this yourself, you can always hire an electrician that works with electric motors. In any case, the PM66 is a great saw and I expect you will be very happy with it when you get it running.

--Geoff

[Patrick Curry]

Magnetic starters for motors are designed to work with several sizes of motors, with the interchangeable heaters (overloads) sized to the amp-rating of the specific motor it's being used with. There are several sizes of starters (00, 0, 1, 2, etc.) that each work with a certain range of motors. It may be that that the starter on your saw is sized to work with both 1-phase and 3-phase 3hp motors, in which case you'll only need to change the heaters, which isn't especially expensive or difficult. Or it may be that the starter on your saw is sized to work with the 3-phase 3 hp motor, but is too small for use with a single-phase 3hp motor, in which case you'll need to replace the starter (or use a smaller motor.) With the saw unplugged you can remove the cover from the starter on the saw. Inside the cover there should be a chart of heaters that will work with the starter. Check the amp rating on the single phase motor, and see if that number appears on the chart of heaters. If it does, then you just need new heaters. If you're comfortable doing this yourself, you can always hire an electrician that works with electric motors. In any case, the PM66 is a great saw and I expect you will be very happy with it when you get it running.

--Geoff
Geoff,
A big thank you for the information. I'll check the existing starter on the TS tonight to see if it would work for a single phase replacement motor. (Baldor $385)

I also found the correct VFD (TECO FM50-203C $200). The VFD would save me a bit of money but I'm going to watch the installation video before making any decisions.

Yes, I'm excited to get the PM up and running . It has the old style fence but I believe it to be in good working order since the shop teacher had been using it. He ordered the saw for the middle school in 74' and took it out of commission when they closed shop in the mid 80s but kept the saw there for school needs. They closed the school down and now he has a garage filled with PM 3 phase equipment! He invited me to keep loading my trailer with low ball prices but I somehow managed to show some restraint.

[Tom Trees]

<p>
Hi Paddy Currently running a 3 phase 3 hp motor on my tablesaw with no issues. I have both of the cheapest VFDs you can get, costing around a hundred quid each. These inverters are the Huanyang 2.2KW or 3HP VFD /inverter tomato/tomato. Both look the same, but the newer ones are quiet (auto shut off cooling fan technoligy) Depending if your the type that would be annoyied by a fan, I would probably go with the cheapest and newer(I think) Isacon/askpower drive again. Im big into safety switches, you will need to either copy Carl Holmgrens design on his TS, or buy a 5 quid relay to enable a stop station ... A stop station (a green start and a red stop switch) is called three wire control. You can buy these switches for like a quid or so a piece on the bay. What your looking for is a green NO (normally open) switch/button, and a red NC (normally closed) the cheapest you can find. I actually have to buy a relay yet for my bandsaw, as I have just wired a light switch for now. I made some brackets and affixed them to the TS, to have a board hung by an old door hinge. There is a dowel protruding out the back of the board to hit the stop switch, and a hole beside it for the start switch.... (which is very safe, as you cant turn it on if your fingers are too fat to go into the hole, because you will be hitting the stop too, at the same time, so it wont work). I have the parameters for the Huanyang and the Isacon/Askpower 3HP/2.2KW drives (you would probably be able to find my threads, of you cant ask me) The most effort is making the cabinet for the VFD to go in, and making a box for the two switches if you dont buy the expensive button stations. Here are some photos</p>

[Bill Dufour]

What your looking for is a green NO (normally open) switch/button, and a red NC (normally open) the cheapest you can find.

Correction: red stop should be normally closed. NC
Bill D

[Tom Trees]

<p>
Thanks Bill Getting late here </p>
<p>
https://www.sawmillcreek.org/clientscript/ckeditor/plugins/smiley/images/images/smilies/smile.gif Well spotted!</p>
<p>
Mistake sorted</p>

[Bill Dufour]

If you have a three wire control system it is easy to add another stop switch in series. maybe on the back end of the machine.
Bill D

[Bill Dufour]

Vocabulary lesson on motor control. feel free to let me know if I get things wrong. This is for a real industrial type push button station control system.

Switch= push button, low amps may be 240/120/24 volts. There can be multiple switches anywhere you want them.

Contactor=relay to turn power on/off to the motor. May also contain extra low voltage switches for control wiring

Overloads=(optional but strongly recommend) downstream of the contactor. Circuit breaker that shuts down if amp draw is too high. It also has extra low voltage control switches.
Two kinds of overloads= the old type with a replaceable heater for each line. the heater is sized for load amps. The newer type has an adjustable heater that can be turned within a range of amps.

Motor starter= contactor+overloads wired together in one box. there may be a transformer if lower voltage controls are used.


For some reason my $105 VFD has to use a stop switch which is NO so adding extra stop switches Is problematic. I have to make sure the Contact block has NO as well as the more standard NC for stop switches. To be honest i have not really figured out the stop method. right now my lathe is wired forward and reverse with it stopping in neutral. The manual is terrible and it mentions Jog speed etc but not how to activate the jog function.
It also mentions three or four stop modes but not how to activate "stop" function.

One big advantage of a real motor control is if the power goes out for a second the tool shuts off until the go button is pushed again. No worrying, with the lights out, how to turn off the machine before it restarts and bites you.

Bill D

[Bill Dufour]

If your existing motor control uses a 208 volt coil that should work fine on 240. Most likely there is a transformer that may need to have a jumper moved on the input side. I would think it is probably 24 volt control.
I have used lighted stop switches to make it easy for anyone to figure how to turn off the machine. Green not so much. If you do not know how to turn it on you should not be using it. But if something bad happens I want anyone to quickly figure out how to turn it off

[Tom Trees]

Have you got the isacon/Askpower drive too Bill?
I probably will be getting another in some distant time ahead for tablesaw no 2, or whatever I may stumble across.
I was looking for a relay for the old Huanyang drive I have, at the time, I did not know the relay was in the terminals allready for the switches.
Unfortunatly the Isacon/askpower drive does not seem to have this, so I put it on the bandsaw instead, as I wanted the saftey of the handsfree paddle style switch
on the TS.
I stuck a regular light switch on the bandsaw cabinet for the moment ...
I dont have an isolator switch to provide power to my machines, instead I just plug them out, so this light switch has nothing to do with
mains power, those other switches are now redundant for the time being.
Make sure you get a single phase in VFD by the way.

[Chris Hachet]

Geoff,
A big thank you for the information. I'll check the existing starter on the TS tonight to see if it would work for a single phase replacement motor. (Baldor $385)

I also found the correct VFD (TECO FM50-203C $200). The VFD would save me a bit of money but I'm going to watch the installation video before making any decisions.

Yes, I'm excited to get the PM up and running . It has the old style fence but I believe it to be in good working order since the shop teacher had been using it. He ordered the saw for the middle school in 74' and took it out of commission when they closed shop in the mid 80s but kept the saw there for school needs. They closed the school down and now he has a garage filled with PM 3 phase equipment! He invited me to keep loading my trailer with low ball prices but I somehow managed to show some restraint.A good sized enclosure on the back of the saw will help with heat issues as you will develop a bit of heat if you ahve extended sawing sessions. I also vacuum out my VFD enclosures with a HEPA (festool) vac every so often to keep the inevitable dust away from them.

[Don Jarvie]

I've done the same motor swap on my 66 and it was the same year, 1974. If the new motor has an internal overload protection then having the overload protection via the starter isnt necessary. If the motor doesnt you will need the heaters in the starter. A magnetic starter is nice but you could use a 30 amp toggle switch (light switch type) since the magnetic starter will be just used for on/off.
Im my case the motor didnt have any interal overload so I had to replace the starter and adaquate heaters. If you want to use a magnetic starter you will need a Size 1 to handle a 3hp single phase motor. Most likely the starter you have is a Size 0 which is fine for a 3 phase motor but not a single phase. I liked the way the Furnas starter looked so I found a Size 1 on Ebay that fit my enclosure.
The motor size is a 145TC. You can use a 56C but you will need to replace the pulley since the 56 have a 5/8 shart compare to the 145 which is a 7/8 shaft. You will need a C frame since the motor bolts to the frame. I got a 56C so I swapped out both pulley so the matches. Suplus Center has pulleys and belts for short money.

[Bill Dufour]

If you do use a standard wall switch make it is two pole so it breaks both hots not just one. Good luck finding a 30amp switch for less then a used contactor.
Bill

[Curt Harms]

I must be looking at the wrong models. The Teco I spec’d out was $320.

http://dealerselectric.com/230V-single-phase-input.asp?cID=50&scID=182&gnsPvar=&gnsPatt=6531788&gnsBrnd=&gnsPrge=&gnsScat=&gnsRev=&gnsScTree=&gnsTid=123456804&SortBy=&GdPageSize=20

[andy bessette]

VFD is useless on a tablesaw. Replace the motor and resell the old one to recoup part of the cost.

[Tom Trees]

<p>

VFD is useless on a tablesaw. Replace the motor and resell the old one to recoup part of the cost. I haven&#39;t read something I have disagreed with so much, for quite a while! You prob have a huge amp rating on your circut breaker,.... Me ? I have a 30a MCB with a 13a plug ...and around 40 feet of distance between them. I would blow the fuse every time if it were single phase motor...I can tailor the machine to whatever surroundings Im in. Even if you did find a second hand single phase 3HP motor (guessing the MCB in your consumer unit for the machine, has like over 80a?) I would keep the dual voltage (has it been stated?) 3 phase motor for another project. Thats my 2cents</p>

[andy bessette]

<p> I haven&#39;t read something I have disagreed with so much...

I'm simply heartbroken.

[Geoff Crimmins]

http://dealerselectric.com/230V-single-phase-input.asp?cID=50&scID=182&gnsPvar=&gnsPatt=6531788&gnsBrnd=&gnsPrge=&gnsScat=&gnsRev=&gnsScTree=&gnsTid=123456804&SortBy=&GdPageSize=20

While a table saw won't use the variable-speed feature of a VFD, and VFD will work fine as a phase converter on a table saw. I have a friend who put a VFD on an 8" Powermatic 60 jointer that has a 3-phase motor. Works great.

--Geoff

[Don Jarvie]

Will the VFD provide the full 3 hp or less? If it doesn’t give the full 3 hp then it’s worth the motor swap.

[Tom Trees]

Yes it will, I have been ripping iroko at near full depth without any signs of being underpowered

[Mike Henderson]

Will the VFD provide the full 3 hp or less? If it doesn’t give the full 3 hp then it’s worth the motor swap.

A VFD will operate a 3 phase motor exactly the same as if you hooked it to 3 phase power from the grid - as far as HP is concerned. It will also allow you to vary the speed.

VFDs provide three phases, each at full voltage and current. it is not like some of the workaround "phase converters" which only provide two phases and thus the motor does not provide full HP.

Mike

[Bill Dufour]

Make sure the motor and vfd are rated for the same voltage. If your motor is like 440/680 volts it will be cheaper to replace the motor.
Bill D

[Matt Day]

VFD is useless on a tablesaw. Replace the motor and resell the old one to recoup part of the cost.

Seriously? For one thing a bit of motor breaking is a nice feature on a table saw. Also 3 phase motors are bomb proof. It’s also a lot cheaper to add a vfd than buying a Unisaw specifically motor - PM66 motors are cheaper since they aren’t specific.

[Tom Trees]

I must say I dont have much breaking on my motor, I think I programmed 7 seconds ...
must look at the parameters I set again. (on a wee sheet somewhere)
I read that you should be aware what way the arbor nut tigthens, as it may come loose if you stop the saw too quick !!!
On my Startrite saw, the arbor nut tigthens the opposite way to the other Italian saw I have .
Can this jam the nut also ???

I haven&#39;t tried to test the Isacon/Askpower drives built in breaking I have BTW
The Isacon/Askpower has no terminals for a breaking resistor also, and the Huanyang has terminals,
but needs components soldered to enable the resistor to work,...
Theres a funny thread where someone used a hairdryer for this!

It might be wort looking up Wadkin Temple Jacks ones on youtube, if your looking for a VFD
Tom

[Mike Henderson]

Seriously? For one thing a bit of motor braking is a nice feature on a table saw. Also 3 phase motors are bomb proof. It’s also a lot cheaper to add a vfd than buying a Unisaw specifically motor - PM66 motors are cheaper since they aren’t specific.

Matt hit the nail on the head. About the only thing that can go wrong on a three phase motor is the bearings fail. Single phase motors have problems with the starting capacitor and the centrifugal switch - a lot more often than bearings.

This is assuming you don't overload the motor and burn it out, of course.

Mike