200v 3 phase motor with VFD, will this work?

Cue · Jan 12, 2017

Hi, I am new to VFD's and despite all of my reading before buying items I think I overlooked the voltage on the motor I bought and not sure if it will be OK.

I have 220 single phase in my shop, measured with a meter it is around 245v. I bought a Teco FM50 VFD, this one here

1 HP TECO VFD 23 VAC 1PH INPUT 3PH OUTPUT

The motor I bought is a Marathon 143TTFR16038 1HP motor but I didnt realize it was 200v instead of 208-230v.
This is the motor I bought.

MARATHON 1 HP 18 RPM TEFC 2 VOLTS 143T 3 PHASE MOTOR NEW SURPLUS | eBay

Will this motor be OK running it thru that VFD? From what I have gathered as long as its not run at full speed for long periods it may be OK?
I am using it to convert my tabletop Milling machine.

Thanks for any info.

Jraef · Jan 12, 2017

In your VFD programming, it requires that you enter the motor nameplate voltage. Enter it exactly as the nameplate says. The VFD will take care of it from there, as long as the motor nameplate voltage is less than or equal to the incoming line, and even then, +-10% is typically acceptable.

Cue · Jan 12, 2017

Jraef said:
In your VFD programming, it requires that you enter the motor nameplate voltage. Enter it exactly as the nameplate says. The VFD will take care of it from there, as long as the motor nameplate voltage is less than or equal to the incoming line, and even then, +-10% is typically acceptable.

Thanks for the reply.
I havent received the VFD yet, it should be here this evening. I have looked over the manual online though and didnt see where you set the voltage but I might have missed it. Are you familiar with this exact VFD and the voltage can be set in this one?

JST · Jan 12, 2017

The manual I see for the unit indeed DOES NOT HAVE a voltage setting......????????

I assume that it uses whatever the line has, and only controls below that as frequency changes.

Your only simple option with that would apparently be to select a maximum frequency that is as much lower than 60 Hz as 200V is below your line voltage. I looked to see if there is a way to cheat that by setting max higher and in some other way limiting the frequency so that 200V and 60 Hz would coincide. Did not see one in the parameters.

The last resort would be to set max frequency to (Line volts/200) * 60, and then limiting the control range to allow only 200V/50 Hz. That would be with a remote speed control potentiometer. Assuming your unit allows that, apparently not all do.

That is something I did not know about those units. I will have to file that info away for later use......

Cue · Jan 12, 2017

So basically dont turn the frequency/speed up past 50hz or so to keep from overheating the motor? I dont understand the other stuff you mentioned, as I said I am new to these

JST · Jan 12, 2017

That is the idea. if the full voltage is 60 Hz, then (200 / line volts) * 60 = max frequency, but there are details

Problem is that the motor is rated for 200 V at 60 Hz, so it will not like 50 Hz at 200V. So you need to set the max frequency at a higher number, so that at the proportion of max that gives 200V, the frequency is 60 Hz.

If your line voltage is 240, then 200 is 83% of 240. So you want to set the frequency such that 60Hz is 83% of the maximum. So 60 / 0.83 = 72 Hz.

If you set the max frequency to 72 Hz, then you should be at 60Hz when you reach 200V.

A nice side benefit is that you CAN turn up higher, because of the way motors work, To the motor, 72 Hz at 240V is the same "volts per Hz" as 60Hz and 200V. So if you set it like that, you can turn up all the way, get a little faster rpm, and not worry. That is not useful unless the machine is OK going above the nominal speed at 60 Hz, which a lathe, for instance, should be OK with.

Jraef · Jan 12, 2017

JST said:
That is the idea. if the full voltage is 60 Hz, then (200 / line volts) * 60 = max frequency, but there are details

Problem is that the motor is rated for 200 V at 60 Hz, so it will not like 50 Hz at 200V. So you need to set the max frequency at a higher number, so that at the proportion of max that gives 200V, the frequency is 60 Hz.

If your line voltage is 240, then 200 is 83% of 240. So you want to set the frequency such that 60Hz is 83% of the maximum. So 60 / 0.83 = 72 Hz.

If you set the max frequency to 72 Hz, then you should be at 60Hz when you reach 200V.

A nice side benefit is that you CAN turn up higher, because of the way motors work, To the motor, 72 Hz at 240V is the same "volts per Hz" as 60Hz and 200V. So if you set it like that, you can turn up all the way, get a little faster rpm, and not worry. That is not useful unless the machine is OK going above the nominal speed at 60 Hz, which a lathe, for instance, should be OK with.

Excellent solution!

Sorry about the misinformation Cue. Been so long since I looked at an FM50, I forgot how cheap and dirty it was. Teco stopped selling them a long time ago now, but the surplus market keeps on spitting them out. Too bad, it really is an inflexible drive by today's standards and there are so many better ones now, usually for the same price point. Oh well.

What JST was saying is to change parameter #6 to a value of 72, it's likely at 60 right now (assuming you bought it from someone in the US). That will "trick" the drive into giving you 200V at 60Hz, which indirectly does the same thing I was telling you. Just be aware that you will now be allowing yourself to run the speed up PAST 60Hz to 72Hz, whereas right now you would max out at 60. Shouldn't hurt anything if you do though.

mike_kilroy · Jan 12, 2017

Makes your own 1hp motor into a solid 1.2hp motor with nameplate of 1.2hp, 72hz, 2160rpm, 240v, base speed. Not bad. 20% more HP for free.

Sent from my SM-G900V using Tapatalk

Cue · Jan 12, 2017

Thanks for the solution!

Cue · Jan 12, 2017

Got it wired up tonight and tried it out, ran it for about 10 minutes and did some light milling, motor didnt get warm at all. I ran it at 35-40 and thats where most of the time I would run it as thats a good speed for what I mill.

Its on a old Jet-16 Mill and I cant believe how smooth it is now, with the old motor I could roughly tell how fast it was going by the sound it made, now even at full speed it doesnt sound like its turning very fast but it is as I checked it with a tach

Thanks again for the info.
.

mike_kilroy · Jan 13, 2017

Great job giving final feedback how it worked out! Thanks!

Jraef · Jan 13, 2017

For whatever that's worth, technically yes, more HP. But the same TORQUE. HP is just a shorthand expression of torque at a speed, so yes, more speed = more HP if torque stays the same, which is what the VFD is there for. Most applications work from torque though.

(I know you know this, I added for the benefit of others who read it later...)

mike_kilroy · Jan 13, 2017

Jraef said:
For whatever that's worth, technically yes, more HP. But the same TORQUE. HP is just a shorthand expression of torque at a speed, so yes, more speed = more HP if torque stays the same, which is what the VFD is there for. Most applications work from torque though.

(I know you know this, I added for the benefit of others who read it later...)

Of course. AND it really IS more torque IF he machined in the 1800-2160rpm range since at 2160rpm he does have 20% MORE torque. Course you and most people know that, and he said he usually machines today at 40hz or so anyway. But it sounds good.

JST · Jan 13, 2017

mike_kilroy said:
Of course. AND it really IS more torque IF he machined in the 1800-2160rpm range since at 2160rpm he does have 20% MORE torque. Course you and most people know that, and he said he usually machines today at 40hz or so anyway. But it sounds good.

Torque cuts the chip, it "gets you in the door".

Power controls how many chips get cut per minute, so it is what gets the work finished in a given time. Low power takes longer, and may not be able to cut the chip at a surface speed appropriate to the tooling.

But I don't see the added torque here. Generally you have a constant torque range as speed/voltage increases, then a constant HP range as speed increases but voltage does not, so speed and torque balance out as motor current decreases but speed increases.

Seems the OP would be still in the range of constant torque. As speed increases, back EMF increases, but the driving voltage increases as well, in proportion, allowing the VFD to push the same current (creating same torque) into the motor.

Once you hit the voltage limit, then added speed must reduce the difference between back EMF and driving voltage, so motor current (and torque) would decrease.

TDegenhart · Jan 13, 2017

The Hp output is a direct function of heating.

Tom

Jraef · Jan 13, 2017

TDegenhart said:
The Hp output is a direct function of heating.

Tom

Hmmm... I would change that to say the HP RATING of a motor is a direct function of heating. But still, that is based on the nameplate speed. If you over speed a motor but keep the V/Hz ratio the same and thus the torque the same, you do actually increase the shaft HP output of the motor. I have a machine I designed that uses a 1/2HP 230V motor and I run it at 120Hz 460V via a VFD, the output shaft HP is technically 1HP, even though the motor is rated for 1/2HP on the nameplate.

It's all relative...

mike_kilroy · Jan 13, 2017

Jraef said:
Hmmm... I would change that to say the HP RATING of a motor is a direct function of heating. But still, that is based on the nameplate speed. If you over speed a motor but keep the V/Hz ratio the same and thus the torque the same, you do actually increase the shaft HP output of the motor. I have a machine I designed that uses a 1/2HP 230V motor and I run it at 120Hz 460V via a VFD, the output shaft HP is technically 1HP, even though the motor is rated for 1/2HP on the nameplate.

It's all relative...

Actually the CORRECT wording would be "The Torque output is a direct function of the inverse of heating."

whew!

Cleaner said "The heat output is a direct function of Torque."

You can add if you want, the why: I^2*R loss is the major variable heat producer, and is a direct result of the TORQUE producing current Id. Is magnetizing current is a constant and always there and basically does not vary with load so can be ignored as far as why heat increases with something, like torque.

JST · Jan 13, 2017

Magnetizing current actually goes DOWN slightly with load.... as total current goes up, and more voltage is lost in the resistance and leakage inductances.

mike_kilroy · Jan 13, 2017

JST said:
Torque cuts the chip, it "gets you in the door".

Power controls how many chips get cut per minute, so it is what gets the work finished in a given time. Low power takes longer, and may not be able to cut the chip at a surface speed appropriate to the tooling.

But I don't see the added torque here. Generally you have a constant torque range as speed/voltage increases, then a constant HP range as speed increases but voltage does not, so speed and torque balance out as motor current decreases but speed increases.

Seems the OP would be still in the range of constant torque. As speed increases, back EMF increases, but the driving voltage increases as well, in proportion, allowing the VFD to push the same current (creating same torque) into the motor.

Once you hit the voltage limit, then added speed must reduce the difference between back EMF and driving voltage, so motor current (and torque) would decrease.

Jst, you need one more beer to understand what I wrote. Or stand on your head and read it upside down? Or maybe it is just that today is Friday the 13th...

Yes, he gets MORE torque. But see why - it is indeed upside down thinking...

METHOD 1: IF he sets his VFDs to 1hp, 200v, 1800rpm, then he gets 2.9#-ft @ 1800rpm, but when he continues up to 2150rpm, his constant HP range torque has dropped to 2.4#-ft.

METHOD 2: IF he sets his VFDs to 1.2hp, 240v, 2150rpm, then he gets 2.9#-ft, and when he continues up to 2150rpm, still gets 2.9#-ft.

This is 20% MORE torque in METHOD 2 at same 2150rpm.

mike_kilroy · Jan 13, 2017

JST said:
Magnetizing current actually goes DOWN slightly with load.... as total current goes up, and more voltage is lost in the resistance and leakage inductances.

Right but.... that is why I wrote "Is magnetizing current is a constant and always there and basically does not vary with load so can be ignored"

You say slightly I say basically. Same difference.

200v 3 phase motor with VFD, will this work?

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