PLC
Aluminum
- Joined
- Jan 26, 2009
- Location
- Bay Area, CA
Hi Guys,
Well I ended up buying my second EE locally. This one is a MG - 1948 Vintage, and I am hoping to get it wired up as soon as possible. I am in a bit of a pickle however. Here is/was my plan:
I was planning on using a Rockwell PowerFlex 40 VFD (22B-A012N104) which is rated at 3hp (12 amps). These drives have a 24 VDC source as well as several Digital inputs at their disposal. I was planning to run the control circuit with the 24 VDC source, which would basically be just start and stop. I would set the VFD speed to 60 HZ to drive the AC motor and use the existing DC voltage generated by the Generator/Excitor to power the spindle motor. The problem I am having is that @ 240VAC the Reliance AC motor is rated at 13.2 FLA. VFD's in single phase go up to 3HP, no problem right?. Well looking closer at the drive specs. the drive is rated at 12 amps which seems to be standard. I am assuming the higher draw on the Reliance motor is due to the fact that it is older/less efficient and also because maybe the losses in the generator are included in this rating.
I know that drives are pretty smart these days in terms of overload protection, however I am hesitant to run a under-sized drive (12 amps) with this motor (13.2 amps). I have considered de-rating a 3-phase input drive, however it would be considerably more expensive to go this route as I would need at least 7.5 hp drive. I am not sure if there is anyone that is running a similar setup, or if you have any input. Thanks in advance!
Well I ended up buying my second EE locally. This one is a MG - 1948 Vintage, and I am hoping to get it wired up as soon as possible. I am in a bit of a pickle however. Here is/was my plan:
I was planning on using a Rockwell PowerFlex 40 VFD (22B-A012N104) which is rated at 3hp (12 amps). These drives have a 24 VDC source as well as several Digital inputs at their disposal. I was planning to run the control circuit with the 24 VDC source, which would basically be just start and stop. I would set the VFD speed to 60 HZ to drive the AC motor and use the existing DC voltage generated by the Generator/Excitor to power the spindle motor. The problem I am having is that @ 240VAC the Reliance AC motor is rated at 13.2 FLA. VFD's in single phase go up to 3HP, no problem right?. Well looking closer at the drive specs. the drive is rated at 12 amps which seems to be standard. I am assuming the higher draw on the Reliance motor is due to the fact that it is older/less efficient and also because maybe the losses in the generator are included in this rating.
I know that drives are pretty smart these days in terms of overload protection, however I am hesitant to run a under-sized drive (12 amps) with this motor (13.2 amps). I have considered de-rating a 3-phase input drive, however it would be considerably more expensive to go this route as I would need at least 7.5 hp drive. I am not sure if there is anyone that is running a similar setup, or if you have any input. Thanks in advance!