Single Phase Motor on VFD?

This actually isn't a "parlor" question. Looks like I'll be installing a couple of ABB ACS580's to run a pair of single phase 2HP pumps, and not as an afterthought. That's what the customer had planned all along and we thought they were just mixed up and built them an across-the-line control cabinet.
 
I can understand how this can work with the wiring diagram that shows bypassing the centrifugal switch and the capacitor(s). The drive firmware just needs to know how to send the right signal out through each winding which most standard three phase drives don't have settings for doing that and is why they won't work with a single phase motor.

Franklin, Pentair, and probably other submersible pump manufacturers have had similar drives for some time now, but they load them with firmware specifically designed for running those kind of applications and not so much for general purpose use. Price wise they are pretty proud of those products when you compare them to the cost general purpose drives of similar output rating though.
 
ptonsparky said:
I hadn’t heard of it before, other than Franklin Pumps.
For the cost a typical VFD setup would seem to have been less expensive.
Maybe not, how did it compare?
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Really don't know. This is at a Dehy station for new gas wells. The pumps are for the glycol. Some techs have been doing the install and were just providing the control cabinet, designed and built by our company out west. The customer provided and installed the pumps and I guess wiring things up. Seems that is what they have done in the past. I'll probably just be mounting the VFDs, programming and commissioning. But who knows? Any difference in cost would be peanuts. Seems bizarre that they wouldn't just get 3-ph motors. We will probably eat the cost of the across the line starters. Again, peanuts.
 
Got thinking more about it and sent the following inquiry to ABB motors and drives:

"Can you please provide recommendations for running a single phase motor from a VFD? The motor is a Baldor 35E024G469C1, 2HP 110/220 volt. The VFD is a ACS580. The customer insists that they have done this before, and I understand that our engineer says the ACS580 is rated for it. As an electrician, I am dubious and so would appreciate any clarification. If this is done, can you provide any special parameters/controls that should be implemented?"
 
TwoBlocked said:
Got thinking more about it and sent the following inquiry to ABB motors and drives:

"Can you please provide recommendations for running a single phase motor from a VFD? The motor is a Baldor 35E024G469C1, 2HP 110/220 volt. The VFD is a ACS580. The customer insists that they have done this before, and I understand that our engineer says the ACS580 is rated for it. As an electrician, I am dubious and so would appreciate any clarification. If this is done, can you provide any special parameters/controls that should be implemented?"
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And heeerrres the answer:

"Hi,
The ACS580 output is for a 3-Phase motor.
Either change to 3-phase motor or contact a VFD manufacturer with a single phase output"
 
If you connected a standard 3 phase output to a single phase motor using connection diagrams for the drive linked to in OP, I would think it would create torque and have motor speed that corresponds to output frequency.

But such a drive is programmed to deliver balanced voltage and current to a three phase motor and won't necessarily deliver what the single phase motor is expecting, particularly to the winding that has a capacitor in it when conventionally connected to a single phase source which likely will result in some overheating in said motor and probably at just about any load level as well.

Add: or it may not like the current being drawn and will shut down
 
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ptonsparky said:
It appears Gohz has them.🙂
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So does ATO. Here is their manual:


Glancing at the wiring required, and the comments, If you keep the capacitor in the circuit, you need to run no slower than 80% (48 rpm). I am pretty sure the motors we are dealing with are TEFC with internal capacitors, so it makes little sense to go this route. I can't see it being economical to dissect these motors to eliminate the capacitor and switch.
 
kwired said:
If you connected a standard 3 phase output to a single phase motor using connection diagrams for the drive linked to in OP, I would think it would create torque and have motor speed that corresponds to output frequency.

But such a drive is programmed to deliver balanced voltage and current to a three phase motor and won't necessarily deliver what the single phase motor is expecting, particularly to the winding that has a capacitor in it when conventionally connected to a single phase source which likely will result in some overheating in said motor and probably at just about any load level as well.

Add: or it may not like the current being drawn and will shut down
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Apparently, the motors have to be derated.
 
TwoBlocked said:
Apparently, the motors have to be derated.
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If the drive firmware will provide proper voltage and phase differential to each winding there should be no reason to de-rate the motor.

A drive that is capable of single or three phase input would need de-rated if using single phase input.
 
Hah! We delivered across-the-line cabinet, had a discussion, and will be bring it back to the shop. A number of people hadn't known how to talk, and others didn't know how to listen. The idea of a VFD taking single phase power and running a 3-ph motor, and the idea of a VFD taking single phase power and running a single phase motor was confabueated. No one had seen the later, but when explaining they saw the former, listeners though they meant the later. Another person was asking about the later, but that listener thought they meant the former.

We will be providing 3-ph motors and a VFD cabinet.
 
TwoBlocked said:
Hah! We delivered across-the-line cabinet, had a discussion, and will be bring it back to the shop. A number of people hadn't known how to talk, and others didn't know how to listen. The idea of a VFD taking single phase power and running a 3-ph motor, and the idea of a VFD taking single phase power and running a single phase motor was confabueated. No one had seen the later, but when explaining they saw the former, listeners though they meant the later. Another person was asking about the later, but that listener thought they meant the former.

We will be providing 3-ph motors and a VFD cabinet.
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It should simpler than the explanation!!😂
 
ptonsparky said:
It should simpler than the explanation!!😂
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It would have been very simple if there wasn't such a thing as a VFD for single phase motors! Nobody said there was, just people that thought that's what someone said, and then ...

Imagine if you were told that a customer needed you to install a flux capacitor, like they have had installed before. Then you found out there WAS such a thing. Only that is not what the customer asked for and had never had one installed, and didn't even know they existed!

Huh, reminds me of some screwed up ladder logic I've seen, that would sometimes control things erratically.
 
There is another more major manufacturer of VFDs for single phase motors, a company from the UK called Invertek. They sold in the US mainly through two other companies here called Bardac and Anacon, both of whom most make DC drives, by brand-labeling the Invertek for AC. But more recently, Invertek has been setting up distribution in the US directly under their own name too.

The thing is, they (the single phase versions) ONLY work on PSC motors and Shaded Pole, but Shaded Poke can be used with simple dimmer type controllers anyway, so it’s really just PSC that makes any sense. Cap-Start and Cap-Start/Cap-Run motors that use centrifugal switches are the problems, and those account for most single phase motors that are not on fans and pumps. When you slow them down below the speed at which the centrifugal switches operates, the caps and aux winding comes back into the circuit and can take out the transistors in the drive, or the harmonics of the VFD output get absorbed by the caps and they over heat and blow.

My personal experience with both ATO and Gohz both is less than stellar and neither were listed by any NRTL last time I tried any. In both cases, they are using a 3 phase drive and telling people they work in single phase motors, without proper warnings that they don’t work on ALL types of single phase motors.
 
Jraef said:
There is another more major manufacturer of VFDs for single phase motors, a company from the UK called Invertek. They sold in the US mainly through two other companies here called Bardac and Anacon, both of whom most make DC drives, by brand-labeling the Invertek for AC. But more recently, Invertek has been setting up distribution in the US directly under their own name too.

The thing is, they (the single phase versions) ONLY work on PSC motors and Shaded Pole, but Shaded Poke can be used with simple dimmer type controllers anyway, so it’s really just PSC that makes any sense. Cap-Start and Cap-Start/Cap-Run motors that use centrifugal switches are the problems, and those account for most single phase motors that are not on fans and pumps. When you slow them down below the speed at which the centrifugal switches operates, the caps and aux winding comes back into the circuit and can take out the transistors in the drive, or the harmonics of the VFD output get absorbed by the caps and they over heat and blow.

My personal experience with both ATO and Gohz both is less than stellar and neither were listed by any NRTL last time I tried any. In both cases, they are using a 3 phase drive and telling people they work in single phase motors, without proper warnings that they don’t work on ALL types of single phase motors.
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I don't see why it can't work on a CS-CR motor if you bypassed the capacitors and the centrifugal switch and the drive were programmed to deliver the current needed for the motor to operate as it was intended. Most three phase general purpose drives won't have the firmware to do this though. The submersible pump motors I have seen these used for particularly Franklin and Pentair drives have parameters to select the motor type and you do not connect the control accessory that came with the motor that has the potential relay and start capacitor, or if over about 1.5 HP they may also contain a run capacitor. The drive software totally controls current and phasing delivered to main and aux winding to give desired performance at any operating frequency.

I have noticed that the well guys tend to set up new installs from single phase supply with the drive and a three phase submersible motor though. I don't know if they have had better luck with that or if there is other reasons to do so.
 
kwired said:
The submersible pump motors I have seen these used for particularly Franklin and Pentair drives have parameters to select the motor type and you do not connect the control accessory that came with the motor that has the potential relay and start capacitor
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Sure, because they (Franklin) have control of every aspect: the start cap is outside of the motor anyway so not connecting it is possible and they don’t use a centrifugal switch. But for someone else to blankety say you can use their 3 phase drive on any single phase motor without qualification about making modifications to the motor, which is not always possible, means destroying one or the other.
 
Jraef said:
Sure, because they (Franklin) have control of every aspect: the start cap is outside of the motor anyway so not connecting it is possible and they don’t use a centrifugal switch. But for someone else to blankety say you can use their 3 phase drive on any single phase motor without qualification about making modifications to the motor, which is not always possible, means destroying one or the other.
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Never seen one in use but those drives supposedly will drive (by selecting the right parameters) a two wire submersible pump motor as well.

Never taken a two wire pump assembly apart, but kind of have to presume it is either PSC, has start switch, or even a start capacitor. Any capacitor obviously would be in the submersible assembly.

Most the two wire submersibles I have run into are on somewhat shallow wells (like 30 to 50 feet deep) and often are out in a pasture providing water to an open piping outlet to a tank for livestock drinking water.
 
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