Help with 3 Phase Converter

J

jim609

Member
Location
Phoenix, AZ
Occupation
Electrical Contractor
I hooked up a lathe to a digital 3 phase converter. I used a cheaper converter so maybe that is the problem but I am getting nothing with the lathe. The contactor does not even seem to kick in. Any ideas? I connected the converted to the main power not directly to the motor and the lathe is in a bad place to try and open the area that houses the contactor but I do not hear it click when I press the start button. Any ideas?
 
is it a Vevor Converter? Symptoms sound like it. They only work when wired directly to the motor.
They are not a digital phase converter, it's a capacitor control to start and run a 3Φ motor on 1Φ.
You can read more HERE
 
In general, many electronic boxes, whether variable freq. drives (VFD) or solid-state phase converters, don't want anything but wire between them and the motor. (If in doubt, check the mfg's instructions.) If you want the lathe to behave as if it has a real three-phase feed, you'll have to give it one.
 
What is the model? Or can you get a photo of it for us? I used to use a lot of these VFD type devices for exactly what you are doing! :)
 
Thanks everyone, i threw it away and am going with a rotary converter. It was a capacitor electronic converter, garbage or wrong application on my part. (Trying to be cheap).
 
There are vfd’s that have 1phase input and 3 phase output. Very affordable and they put out a good 3phase sine wave. Technology these days is great.
 
Rpmmillwright said:
There are vfd’s that have 1phase input and 3 phase output. Very affordable and they put out a good 3phase sine wave. Technology these days is great.
Click to expand...

They work great for their target application, but are horrible if used incorrectly.

VFDs are designed to work with motors, and _require_ the motor inductance to smooth the ugly high frequency pulsed output into a reasonable current sinewave. If you try to use a VFD to run the motor of a lathe you will probably have great results. If you use that same VFD to run the entire lathe (including any electronic controls), you will probably have terrible results.

If you need a true sine wave output there are converters that will do this, but they cost a bunch more than VFDs because of the required output filtering.

To the OP: be careful about the issue that @kwired raises. A rotary converter passes the supplied single phase directly to its output, so the supplied single phase is usable for things such as control circuits. But the generated third phase is really only intended for motor loads.

-Jonathan
 
Rpmmillwright said:
There are vfd’s that have 1phase input and 3 phase output. Very affordable and they put out a good 3phase sine wave. Technology these days is great.
Click to expand...
YES! All GA series Yaskawa VFDs will convert single phase to three phase. Use a correctly rated line reactor, and size the drive 3x to the full amperage load. Message me back if you need help with sizing the drive. I'm a Yaskawa dealer in the Kansas City area.

I need the full rated amperage of the lathe and the voltage, I'm assuming it's 240vac.

Capacitor type or rotary phase converters are junk. At least the Alibaba/Vevor type ones.
 
It's important to connect the drive directly to the motor. The contactor won't be used in this new controls system. The controls of the lathe need to be on single phase power still. The speed and start controls will be directly on the drive, not on the controls of the lathe. You can start the lathe by pressing run on the drive, and stop the same way. If the drive is in a remote location, you can build a small "stop/start" station next to the lathe with simple switches and buttons. A potentiometer is used for speed remote, or if you want single speed it can be set up that way.
 
winnie said:
They work great for their target application, but are horrible if used incorrectly.

VFDs are designed to work with motors, and _require_ the motor inductance to smooth the ugly high frequency pulsed output into a reasonable current sinewave. If you try to use a VFD to run the motor of a lathe you will probably have great results. If you use that same VFD to run the entire lathe (including any electronic controls), you will probably have terrible results.

If you need a true sine wave output there are converters that will do this, but they cost a bunch more than VFDs because of the required output filtering.

To the OP: be careful about the issue that @kwired raises. A rotary converter passes the supplied single phase directly to its output, so the supplied single phase is usable for things such as control circuits. But the generated third phase is really only intended for motor loads.

-Jonathan
Click to expand...
even the digital converter mentioned originally by OP likely somewhat crude phase converter but has good enough output pattern to work to supply a motor, but if OP happened to put it in the main supply and there is more to the machine than just one motor it maybe doesn't work so well.
 
herding_cats said:
YES! All GA series Yaskawa VFDs will convert single phase to three phase. Use a correctly rated line reactor, and size the drive 3x to the full amperage load. Message me back if you need help with sizing the drive. I'm a Yaskawa dealer in the Kansas City area.

I need the full rated amperage of the lathe and the voltage, I'm assuming it's 240vac.

Capacitor type or rotary phase converters are junk. At least the Alibaba/Vevor type ones.
Click to expand...
Rotary phase converters are not a problem. You do need to have approximately two times size idler motor as the largest motor you will be starting though. And they will allow multiple motors to start and stop individually. Capacitor type usually require derating the motor you will be supplying.

Pretty much all general use VFD's can be utilized to convert single to three phase. If not specifically labeled for certain ratings @ single phase input then you usually will need to double the drive size current wise. Technically should only need to be 1.73 times the size. You still powering the same DC bus but only have two lines for input instead of three and it will need to be larger rectifier to handle it. Output side doesn't need to be larger but they only do this larger input thing with models specifically marked for single phase in and three phase out, all others need to be derated.
 
I've done this at 1.73x and have had nuisance tripping. This was on HVAC compressors, so I go to 3x now just to be safe and get a long lasting drive. Maybe it's overkill but it insures it will work. The cheap rotary converters from Alibaba are junk. Higher quality ones would be fine.
I recommend using a line reactor as well. Galco.com is a pretty good source for them.
 
kwired said:
even the digital converter mentioned originally by OP likely somewhat crude phase converter but has good enough output pattern to work to supply a motor, but if OP happened to put it in the main supply and there is more to the machine than just one motor it maybe doesn't work so well.
Click to expand...
I think that is his issue? He's got the converter hooked up to the main power, not the motor directly. The converter would be for direct motor wiring only.
 
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