VFD for single phase induction motor?

Is this possible? I have a customer, a glass artist, who uses several
very nice but old glass grinding machines. There are only 4 speeds on
these machines and he would really like more speeds. He has a newer
machine with a VFD on it and asked me how he could get the same thing
on his old machines. I told him he really needs to change motors to 3
phase. But he is loathe to do that. I can see why. First of all the
motors are beautiful. Secondly they are protected from the water that
splashes on them, being totally enclosed. They also run very smoothly,
having a run cap and great plain bearings. I would want to keep these
old machines original too. Anyway, is there any sort of practical way
to feed a cap run single phase from some sort of variable frequency
drive?
Thanks,
Eric

 

[Jasen Betts]

On 2018-09-28, etpm@whidbey.com <etpm@whidbey.com> wrote:

Is this possible? I have a customer, a glass artist, who uses several
very nice but old glass grinding machines. There are only 4 speeds on
these machines and he would really like more speeds. He has a newer
machine with a VFD on it and asked me how he could get the same thing
on his old machines. I told him he really needs to change motors to 3
phase. But he is loathe to do that. I can see why. First of all the
motors are beautiful. Secondly they are protected from the water that
splashes on them, being totally enclosed. They also run very smoothly,
having a run cap and great plain bearings. I would want to keep these
old machines original too. Anyway, is there any sort of practical way
to feed a cap run single phase from some sort of variable frequency
drive?

Disconnect the capacitor and use three phase drive,

Thanks,
Eric

--
ŘŞ

 

On Fri, 28 Sep 2018 23:21:30 -0000 (UTC), Jasen Betts
<jasen@xnet.co.nz> wrote:

On 2018-09-28, etpm@whidbey.com <etpm@whidbey.com> wrote:
Is this possible? I have a customer, a glass artist, who uses several
very nice but old glass grinding machines. There are only 4 speeds on
these machines and he would really like more speeds. He has a newer
machine with a VFD on it and asked me how he could get the same thing
on his old machines. I told him he really needs to change motors to 3
phase. But he is loathe to do that. I can see why. First of all the
motors are beautiful. Secondly they are protected from the water that
splashes on them, being totally enclosed. They also run very smoothly,
having a run cap and great plain bearings. I would want to keep these
old machines original too. Anyway, is there any sort of practical way
to feed a cap run single phase from some sort of variable frequency
drive?

Disconnect the capacitor and use three phase drive,

Thanks,
Eric

And how do I use three phase drive on a two phase machine? Really, I
have never heard of doing this. I can use a regular three phase output
VFD to run a two phase motor?
Thanks,
Eric