460 Volt???

[Derek Arita]

I'm looking at a DP that has a 2HP, 1PH, 460V motor. Is there any way to run this on 220V, 1PH power, 20 or 30A, power?

[Ken Garlock]

Derek, I would pop the lid on the motor junction box and look for a diagram on the inside cover that just might have an alternate configuration for 230V. :)

[Derek Arita]

This is a new Powermatic 1203795 DP that is 3PH, 460V not 1PH. My mistake. To complicate things, it has an EVS system to change speeds. I don't have access to one to be able to look at diagrams on the motor. Think I can use this in my 220V, 1PH shop?

[Roger Everett]

Derek:
If it's 3 ph, you will need a phase converter, and they start at "mucho danaro".If you have it already, alot cheaper to replace motor.
Roger

[Larry Reimer]

Derek, how bad you want that? Yes, it could be made to work, but you may very well be talking about a boost transformer and phase converter. Or you may be able to make that work with a frequency drive, but then that would probably interfere with the EVS. Any of those options would cost more than the project's worth (in my opinion).

[Richard Wolf]

Where's Dev when you need him??

Richard

[martyphee]

This is a new Powermatic 1203795 DP that is 3PH, 460V not 1PH. My mistake. To complicate things, it has an EVS system to change speeds. I don't have access to one to be able to look at diagrams on the motor. Think I can use this in my 220V, 1PH shop?

You won't be able to use the VFD on it if you don't go 440v 3ph. VFD's are designed for certain voltages and can't be changed.

Option one. Build a phase converter and get a transformer. The dp probably only has a 1 or 2hp motor so you'll only need a 3hp rotary phase converter. If you can get a used 3ph motor it should cost you less than $100 for a rotary converter panel off of EBay. Then you need a 220v -> 440v 3ph transformer.

Option two. I would almost guarentee that the motor can be either 220 or 440. That means you'll need a 220v vfd off Ebay. Most vfd's can run on 1ph power and at that HP you will get almost full hp out of the dp. Again a 1-2hp vfd shouldn't cost much on Ebay.

Option three. Tell me where the dp is so I can buy it... ;-) I run 440v 3ph in my shop.

I even have a Yates y-20 BS which I use a 440v vfd on. Work very well with my 440->220v transformer wire backwards. Most transformer will be rated for going from 440 to 220 voltage. All you need to do is wire it backwards and you get 440 out of 220.

On mine I went from 220 1ph to 440 1ph then to my converter which gave me 440 3ph. I do not suggest that you do this. Buy an individual transformer for the 440 equipment. This will allow you to use regular 220 3ph equipment when you come buy it.

Your talking about $3k to $4k machine here.

Marty

[Chris Padilla]

Derek,

The easiest route would be to get a 1 phase motor of whatever HP you want. In the long run, it will probably be the cheapest way to go as well as being easier....

3-phase is great if you have access to that kind of electricity but most of us do not.

[lou sansone]

I tried to look at all the maunals and other powermatic info.
From what I can see this particual model number is strictly made for 460 3 phase. there is another similar model 1203794 that can be used either on single phase or three phase in the 230 volt range. For what ever reason it looks like the 1203795 is strictly for 3 phase locations.

why don't you buy the 1203794? BTW these guys are pretty pricey. Are you buying it new?

For those who also answered this post, with all due respect I believe that you have not taken a careful look at this unit. It already has a 460 v three phase VFD on it! I have used VFD's before and they work great. As may of you know I also have a 3 phase shop. my experience with VFDs is that for 230 volt you can get them in single phase input and 3 phase output, three phase in and out. For the 460 volt units, they pretty much come 3 phase in and out at 460. I agree that many 3 phase motors are 9 wire motors and can often be changed from 230 to 460. But not all are. As I read the powermatic manual it seems that this particular unit is a strict 3 phase 460 unit. It may be a way of saving money in tiawan.

I am not sure I followed all of marty's train of thought. I agree with him on most of it. Did you boost the 230 single to 460 single and then find a 460 single phase VFD? I have not run across them, but that is not to say they don't exist. I would think that you would really need to get this DP at a real steal to make it worth the effort to have transformers and a new VFD.

lou

[Rob Russell]

Lou's post has a lot of good points in it. You're not likely to find a 460v VFD that will work on 240v single phase input.

Let's assume that you're getting this DP at a real steal. IMO, the best way to power it is to use a rotary phase convertor to generate your 3rd leg at 240v. Feed the 240v 3-phase into a 480/240 transformer to boost the voltage to 480v and feed that into your drill press.

You can get both the RPC and transformer on ebay. Look at item #7529980413 as an example of the RPC you want. Look at item #7528389821 as an example of the transformer - in fact that transformer is probably pretty much exactly what you want - you need a transformer wired for 3-phase Delta, not 3-phase "Y".

Rob

[martyphee]

I am not sure I followed all of marty's train of thought. I agree with him on most of it. Did you boost the 230 single to 460 single and then find a 460 single phase VFD? I have not run across them, but that is not to say they don't exist. I would think that you would really need to get this DP at a real steal to make it worth the effort to have transformers and a new VFD.

lou

I have a single phase transformer boosting my voltage from 220->440. It's a 15kva transformer that I got for $50. This gives me 440 volts that I needed for my Greenlee 227 mortiser. The reason I say don't do this is that some motors are either 220 or 440 only. My greenlee is 440 only while my 18" delta wedge bed was 220 only. I didn't realize that my planer was only 220 until after I setup my rotary converter. I had to switch out my 7.5hp for a 5hp motor. Better off making a 220 3ph and use a transformer where needed.

If this is only a 440 machine then you'll need the rotary converter with a 220->440 3ph transformer. If you plan on expanding your shop (more machines) make yourself a 7.5-10hp rotary converter. This will give you lots of options for machines in the future. Many people are scared of 3ph machines and you can pick them up cheap.

Oh, and no there not that expensive if you plan on doing some of the leg work.

[martyphee]

Lou's post has a lot of good points in it. You're not likely to find a 460v VFD that will work on 240v single phase input.


I would say that you'll never find one. The electronics are made for either 220 or 440. You need a transformer to boost the voltage.

[martyphee]

Derek,

The easiest route would be to get a 1 phase motor of whatever HP you want. In the long run, it will probably be the cheapest way to go as well as being easier....

3-phase is great if you have access to that kind of electricity but most of us do not.

That really might not be the easiest since the vfd is on there to change the speed. There probably isn't any way of changing speed (pulleys or reeves pulleys) unless you have the VFD and VFD's won't work on 1ph motors.

[martyphee]

Derek, how bad you want that? Yes, it could be made to work, but you may very well be talking about a boost transformer and phase converter. Or you may be able to make that work with a frequency drive, but then that would probably interfere with the EVS. Any of those options would cost more than the project's worth (in my opinion).

EVS = VFD - Nothing fancy here just marketing terms.
All you need is the 3ph. I use a rotary conveter and transformer with a 440v VFD on my Y-20.

[Jim Becker]

EVS = VFD - Nothing fancy here just marketing terms.

Not marketing in the case of VFD. VFD refers specifically to variable frequency drive and applies specifically to 3-phase equipment. It changes the cycles per second that the AC power switches back and forth to govern the speed of the 3-phase induction motor. EVS (which is a marketing term) is generally different technology and is designed for small, single phase universal motors. It plays with the voltage, to the best of my knowledge.

[lou sansone]

Not marketing in the case of VFD. VFD refers specifically to variable frequency drive and applies specifically to 3-phase equipment. It changes the cycles per second that the AC power switches back and forth to govern the speed of the 3-phase induction motor. EVS (which is a marketing term) is generally different technology and is designed for small, single phase universal motors. It plays with the voltage, to the best of my knowledge.

Hi jim
I think that given the fact that this particualr powermatic DP has a 2 hp TEFC motor on it I would have to conclude that this particular EVS is indeed a VFD by a different name. Once in a great while you will find a universal motor greater than 1 hp, but they are usually really old motors from the 20s and 30s. As I looked over the manual on this machine in question it really did seem that it was a true 3 phase motor being controlled by the VFD. I could be wrong though.

lou

[Dev Emch]

I have been lurking here and pinged the orig. poster on the back channel.

VFD technology has much more going for it than just variable speed. Units by TECO and Allan Bradley can do all sorts of things and some have computer interfaces using RS-232 type communications and the newer ones are based on profi-bus. Some of these units can actually be used to replace the standard contactor/starters of days gone by. They also contain internal saftey overload features that replace heaters and overload relay blocks.

The use of VFDs in woodworking machines for the control of speed actually began with lathes. The top end lathes often used variable speed DC drives which consist of a DC motor and a variable voltage supply. These are very expensive. Examples of new woodworking lathes with VFD based speed control come on the market with machines like the general 260 lathes and later some of the powermatic lathes. Today, the most popular variable speed lathe drive is that of a VFD and a three phase induction motor. Often, this drive can be run from either single phase input or three phase input. The downside to this type of drive is that of torque loss. Depending on how you program and configure your rig, there are cases where your HP remains constant but your torque takes a nose dive. That is because torque is expressed as an equation with RPM in the denominator.

As you go to 440 volts, you will find that three phase is more popular. The reason is simple. In the old days, shapers needed to run at say 7200 RPM but these were direct drive machines with 3600 RPM motors. There was a device whose nickname was called a "FREQ". A freq consists of a 60 cycle three phase motor directly coupled to a motor running as a generator. This generator had slip rings on the outside and from there, 120 cycle power was picked off and fed to the shaper thus driving it at two times speed. This was called "Freqing" the shaper. Although a VFD can do the same job, the problem is that nameplate HP and torque are generated at 3600 RPM. As I go higher up, my HP remains constant but my torque begins to dive down significantly. However, there are special types of motors called "sycnonous induction motors". These are similar to the plain jane induction motor with one exception. The maintain synconous speed. Your typical induction motor does not run at sycnonous speed but rather slightly less than it. The difference is called the slip. In the syncronous induction motor, the speed is maintained at synconous speed. This particular motor, which is very rare, has one unsual side effect. By wiring the motor to run on 220 volts and using a 440 volt VFD, I can freq this motor to run at 7200 RPM with virtually no loss in torque! I can also control its speed with relative ease.

Metalworking machines often benefit from VFD speed control because the loss of torque does not have a great impact. If I double the speed of a milling machine spindle, it is assumed that I am using a much smaller cutter. Bigger cutter means less speed. Smaller cutter means higher speed. The smaller cutter also needs less torque so I am O.K here. But in the case of say a woodworking planer or jointer, this is not the case. Sure, I can double the speed of a cutter head but that cutter head still needs the same amount of torque to make that same cut. Thus, there are cases in woodworking where VFD speed control may not be a wise thing to do.

A universal motor is called that because it is a DC motor designed to run on AC. In fact, it will run on any line frequency from DC up to its frequency design limit which is often 60 cycles. It has the stator field wired in series with the armature via the commutator and brush set. Being that it is a DC motor at heart, it stands to reason that by varying the voltage, you can vary the RPM. But dont forget that this type of motor derives its horse power output not from torque but from high RPM. Think of a diesel motor versus a racing car motor. Which is more powerful? Clearly that is application dependent.

Universal motors are often very small and have extremely high no load RPM limits. Often these motors tool along at about 20,000 RPM. During the 1920s give or take, there were a group of motors that resembled universal motors but were much larger. These were in the 1/2 to 3 HP range and were heavy and large. Often they resembled standard induction motors but were clearly not induction motors because they had brush barrels on the side.

The pressence of brushes suggested that these were either DC motors or universal motors. In such a case, you need to double check your motor's nameplate for power requirements and RPM!!!!!!!!

Some of these motors are called Repulsion/Induction motors. These were all single phase AC motors which again can trick one into thinking these are universals. When the motor starts, the amature coil has only two opposing coils wired together via the brushes and armature commutator. The armature also had a star shaped disc of copper attached to the face of the armature. As the motor came up to sycnonous speed, this disc began to flex inwards and ultimately shorted out ALL of the coils on the armature. This shorting process thus turned the DC type armature into an induction or squirel cage armature or rotor. The biggest difference between this motor and a universal motor is that the stator coil is not attached to the armature winding as it is in a universal motor. A fact that is not easy to determine without taking the motor apart.

I learned about these during my current restoration of a tiny 6 inch vintage wallace jointer which has a 1/2 HP GE repulsion/induction motor. Today, very few of these are made. Baldor still makes one 3 HP repulsion/induction motor which is used in the essex sliver eight floor sander. But the fact remains that using a DC armature with its correspondingly expensive commutator to start up a single phase induction motor is not the smartest thing to do.

Hope this all helps. Who would have "thunk" it that us wood butchers need to come up to speed on motor electrics to keep our toys running. And for those who remember the shop notes magazine with that super cool 1914ish jointer on the back cover..... well, that is the wallace jointer I am restoring. Complete with a satin black paint job, polished aluminum pork chop and polished machined surfaces all atop a new maple bench stand.

[lou sansone]

hi dev


like I said.. universal motors are not very common... I am pretty sure this dp has a plain jane 3 phase tefc motor and a vfd.
so ...... what is the asking price of the dp
lou

[Don Baer]

I have been lurking here and pinged the orig. poster on the back channel.

The downside to this type of drive is that of torque loss. Depending on how you program and configure your rig, there are cases where your HP remains constant but your torque takes a nose dive. That is because torque is expressed as an equation with RPM in the denominator.



Dev, not to start a debate but having been involved in the motor control industry for over 30 years I feel a need to correct you on this matter. VFD's have two modes. Constant Torque and Constant Hp. In the constant Torque mode the volts/cycle is a constant. On a 230 Volt VFD that means 3.83 Volts/cycle. This is done to keep from burning up the motor from over voltaging the windings.

An AC Motors speed is governed by it the number of Poles it has and the frequency of the applied voltage. a 1750 RPM motor has 4 poles assuming it is running at 60 Htz.

The formula for Hp states that Hp=Torque x RPM/K, where K is a constant if the torque is in inch Lbs the constant is 63025. Lets take a standard 1 HP 4 pole (1750 RPM Motor operating at 230 Volts 60 Htz) you would see that the motor develops 36 in.Lb. of torque. Now if you run the motor at 825 RPM it would only develop 1/2 HP but still have 36 in lb of torque.

A 1 HP 2 Pole motor (3450 RPM) would develope 18 in. lb. torque. That is due to the physical design of the motor (2 Poles rather then 4 Poles)

The other mode of operating an AC Motor is called Constant Horsepower. In this mode the contoller holds the voltage constant but increases the frequency. In this mode we could take the same 1750 RPM 1 HP Motor and run it at 230 Volts 120 Htz. Then the motor would run at 3450 RPM and 36 in. lbs. Thus it would become a 2 HP motor at 3450 RPM's.

Most modern VFD's will use both modes. Contsant torque from 0-base speed (1750 for a 4 pole motors) and constant HP above that.


I Hope this helps.

[Dev Emch]

The data posted by Don is more or less correct. There are actually three main modes of operation for a VFD. The third one is where you have constant torque in a freqing condition and its a very wild application of VFDs and it requires you to input 440 3 phase to the VFD. I learned about this from a TECO/Westinghouse engineer and I am using it to freq a 1961 direct drive, 20 inch porter jointer. Normally these run at 3600 RPM but I like the feel of a faster cutter head such as those found in european jointers. As the motor is still wired for a 220 application, there are lots of chances to burn something out here if your not spot on exact with your programming! This special application is not normally how these units are used. But the loss of torque is serious when your running a 50 pound cutter head that is 5.5 inch diameter log of steel!

VFDs are known for soft starts. This is because they begin to energize the motor at DC and gradually ramp up line frequency until they reach the design line frequency of 60 cycles. You dont get the slamming affect of putting the still motor onto the grid instantly causing the excessive diarc start up pulse currents. This is a nice feature. But generally, the motor is operating in a constant torque mode as it comes up to speed. As the frquency increases, so does the motor RPM and its corresponding horse power output. So, using Don's equation, we get:

Hp = (Torque * RPM)/K

where Torque is considered constant and K is a design parameter constant. This relationship holds valid until we reach 60 cycles at which point the motor has reached its namplate power output and the voltage and current loads are inline with those listed on the nameplate. Mind you, the current will be at an idle level if the motor is not currently loaded as you would find in a table saw or an air compressor whose unloaders are still active. In other words, if all we wished to do was run the motor using a single phase input, then we have succeeded as the VFD is running as a phase converter.

But since we are freqing the motor, we need to change our perspective right now. Lets say my motor is running at its design speed of 3600 RPM and lets ignore slip issues for simplicity. A full freq of this motor would put it at two times namplate speed or 7200 RPM. Again, this example would include direct drive shapers such as the whitney or oliver 287 or some of the moulders such as a vonnegut. In the good old days, you would need a huge machine called a frequency converter or freq for short to perform this task. This is where the name freqing actually came from by the way. One of the nicest out there was made by the Louis Allis corporation. Motors that were going to be freqed were specially designed for this and in the case of the motor I actually saw on an oliver shaper, the nameplate has it listed at 120 cycles.

In the case of using a VFD, you will now switch over from constant torque mode to constant horse power mode which will take you from your normal operating speed to your freq speed. Again, this assumes that we are running a normal induction motor with a VFD running at the same voltage as the motor! Rewriting our equation and taking note of what is constant, we get:

Torque = (Hp*K)/RPM

where Hp is constant as is the design parameter K. Regardless of how you look at this problem, the reality is that power is conserved. Regardless of how I cut up my combination of voltage and current, I will always get the same amount of power. Trying to push a 5 Hp motor to put out 10 Hp is not a wise or long term proposition. So by increasing my speed from my nameplate base RPM to my freq RPM, I am going to loose torque. But my horse power remains constant.

What does this mean? This is where things get a bit confusing. Small high speed cutter bits do not require a great deal of torque to run but they do need the higher speed. So for this application, I am O.K. But the jointer has a 50 pound cutter head and this will act as a fly wheel releasing stored up kinetic energy as torque when it first hits the incomming board. But just as your 3 HP router does, your going to experience a drop in RPM.

Clearly a 3 HP universal motor and a 3 HP induction motor both put out 3 horse power. But the uni has horridly low torque and the induction motor has fantastic torque. But the uni has the extreme high speed for applications like router bits and the induction motor has horrible low speed for this same application. So in cases where bridgeport milling machines had J-heads freqed, the users have had no major issues. In cases where woodworking machines with their constant and massive cutter heads were freqed, the torque loss has been a bit of a problem.

And for those of you who have never seen a freqed shaper come up to speed, your in for a total experience. Its way cool and sounds like a jet engine comming up to speed. Also if your in the market for a used phase converter, beware. A number of dealers have had freqs or frequency converters listed as phase converters as they did not know any better. Make sure your buying a phase converter and not a freq!