3hp VFD with 2hp motor or 2 and 2?

G

gixxer

Joined
Sep 21, 2006
Messages
1,472
Talking about AC drives here... Here's an interesting question. I have read in past discussion that when you purchase a VFD that you get one bigger than the rated HP of the motor you want. Meaning for example that if you have a 2hp motor then you want a 3hp rated VFD. I noticed that looking at those penta drives that unless you have three phase going into the drive, it is only rated at 2hp. You guys feel comfortable using that drive with a 2hp motor right at the VFD rating? I have never heard of any problems at all, just asking the question.

I am about to purchase another VFD for a new motor I got last week. Ironically the motor is a 2hp, and I am ready to buy a 3hp VFD.

http://dealerselectric.com/item.asp?...ID=132&PID=620

I would really like to get one of the Penta drives cause the controls are more user friendly instead of having to push a button each time you want to change speed or direction.
 
I got a 2hp drive for my 2hp. A 1hp for my 1hp. I don't see or know anything is wrong. I really lean into my grinder at times. I wired mine to work remotely with a 5 turn pot and a 2 position switch so the switch controls the direction and the pot controls the speed. 5 turn pots are great because you have finer control.
 
No real reason to get oversized VFD, IMO. I use a 2 HP VFD (these all are configurable to drive lower HP motors, BTW - 1 1/2, 1, 1/2) with a 2HP 3 phase USEM motor.
 
i know that some 3 phase vfd can run of single phase but you have to over size the vfd by 33 percent i think
 
It really boils down to the specs on the drive in question. ...or HOW it is spec-ed. Some drives that run on both single phase or 3 phase inputs...have 2 specs on the output, depending on which input is used. Typically, they are honest ratings....but you have to understand how it is being rated....not like the 7hp shop vacs at the local home hardware stores.


-Rob
 
Actually Rob your opinion was the one I was looking for. I will be calling you as soon as my travel pay clears.:thumbup:
 
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