VFD for 5 HP AC Motor

roadie33

roadie33

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When I bought the Air Compressor at an Auction 10 years ago the motor originally was a 5 HP 3 Phase GE. I ended up replacing it with a 5 HP single phase 220v motor. It has started to get weak and trip the high temp breaker on itself.
I want to put the original 3 phase motor back on and am trying to find a reasonably priced VFD instead of buying another 1 phase motor.
I found this one and it looks like it is the correct size and easy to connect.

This is the plate from 3 phase motor.

1516850242400.png

Here is the VFD I have found.

https://www.ebay.com/itm/UPDATED-22...143307?hash=item19f554944b:g:Y2IAAOSw0LlZlUM9
 
Thanks for the quick reply Mike.
How does the pressure switch wire up with the VFD?
 
to elaborate, the pressure switch would act much like an on or off switch.
the DCM could be connected to one half of the switches normally open or closed contact respectively, and then connected to the forward terminal.
(you would then disable the reverse feature in the Pdxx control parameters, to keep the compressor from running backwards)
but there are other ways to skin the same cat ;)
 
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One nice thing about VFD's, they are kind of a "soft start" for a high starting load motor like a compressor motor. You can set the parameters to bring the motor up to speed in several seconds so you don't have so much current draw on start up.

Seen a soft start unit temporarily wired up to a 300HP gas compressor we were testing. The shop we were in had maxed out all the incoming power the power company would give them. This motor drew more starting current than what was available coming in the building. The soft start unit eased the load by gradually bringing it up to speed in four speed steps. Essentially, the soft start unit was more or less a big VFD.
 
Thanks Mike,
When I get around to installing it I may have to pick your brain on wiring it up.
 
As an alternative, have you checked the capacitors on the single phase motor Mike. My compressor started dimming the shop lights, turned out the start capacitors and one of the run capacitors were shot. Probably cost as much for them as the VFD but was a simple fix.

Greg
 
No, I figure if I am going to spend any green, it will be to get the practically new 3 phase motor back on and running.
When I bought the AC, the owner told me he had the motor gone thru 4 months before the auction.
 
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