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Thread: 5hp VFD
05-13-2010, 06:56 AM #1
I have looked on Automation Direct and Factorymation for this with no luck.
Is there a 230V 5 hp VFD with single phase in and 3 phase out?
If so could you point me in the right direction?
05-13-2010, 07:05 AM #2
05-13-2010, 01:04 PM #3
In most cases, you can use any 10HP 230V 3 phase drive and feed it with 230V 1 phase for a 5HP motor. There are a few exceptions (such as some Allen Bradley drives) that don't allow you to disable the Phase Loss protection, rendering them unsuitable. Just check that issue before purchasing.
Besides the Polyspeed version mentioned above, I believe AC Tech still makes one. But for all intents and purposes, both of these drives are essentially just what I described above, only they changed the label to say it is for a 5HP motor with a single phase input.
By the way, one thing to keep in mind;
Even though, as is the case with that Polyspeed drive, the output current is 17A to run that 5HP motor, the INPUT current from your single phase supply will be 30A! And because the NEC requires that the feeders for a VFD must be 125% of the VFD's max input amp rating, that means you must use a 40A circuit to feed it.
05-16-2010, 03:59 AM #4
Thanks for the info.
Yes, I realize the need for proper wire sizing on the VFD's input. I do this type of work everyday at my place of employment where I work as an Automation Controls Technician/Industrial Electrician.
I though a 10hp unit would do this but wasn't sure.
If I ever go on with this it would be for my air compressor. Just doing some research for when the motor goes on it.
05-16-2010, 05:37 AM #5
Actually, older Allen-Bradley drives, particularly the 1336S and 1336F drives WILL run single-phase in, as well as direct DC feed, so there's no need to be able to disable phase-loss protection. I've got three machines on 1336S's, and one on an F... for economy's sake, these machines are all wired for 480v input, and I'm feeding 480v VFDs through a single-phase 240:480 transformer.
A-B 1305's bigger than 3/4hp will generally work fine in single, and the manual even indicates which models will... my J-head drill and J-mill are both running 1305's... they're fed through control contactors by 240v mains.