VFD on single phase motor

[GRapp]

The post by REK Knives about his VFD led me to start my own rather than interrupt his. I have access to a belt/disc combo at work but it is fixed speed with a single phase, 115V motor. I'd like to apply a vfd to it. It seems many vfd's will input 1 phase but output 3. Are you guys running 3 phase motors on your grinders? Is there a VFD that inputs & outputs 1 phase?

 

[Stacy E. Apelt - Bladesmith]

Yes, VFD grinders and machines use 3-phase power.
You can't run a single-phase motor off a VFD. The cheap "speed control" units used for some tools like routers won't work either. Even if it slows the speed, you will burn up the motor

 

[3fifty7]

I’m in a similar boat, I running a single phase 220v 2hp motor. I have 4” and 8” drive wheels that I swap between.

 

[Stacy E. Apelt - Bladesmith]

The day you get a 56C frame 2HP 3-phase motor and a VFD you will say, "Wow! I never knew what I was missing."

It is well worth the cost.

 

[GRapp]

I looked at VFDs & 3 phase motors. I might as well buy/build a purpose built disc sander.

 

[Ken H>]

Actually there are 1 ph to 1 ph VFDs available, but they are expensive and usually limited to perhaps 1.5 hp? (sorry for long link). This is a blog, and not sales related so should be ok?

VFD’S for Single Phase Motors?

www.wolfautomation.com

Single Phase Input/Output:

• Available from 0.5 to 1,5hp
• For use on permanent split capacitor (PSC) or shaded pole induction motors
• These drives end in -01
• Higher horsepower 3 phase models can be derated for use in single phase power applications.
• Switch between industrial mode, pump mode and fan mode
• 14 parameter basic setup, default settings suitable for most applications
• Internal Category C1 EMC filter

 

[Stacy E. Apelt - Bladesmith]

Yes, they exist, but won't run most common motors and are very expensive. The motors they run are low power. I have never seen shaded pole motor in the 1HP range. IIRC, neither can be run in reverse by a VFD. You have to wire a switch to reverse the coils on a permanent split capacitor motor. I usually onle see PSC motors in the 1/2HP range.
The other big issue is I don't believe they are TEFC.

GRapp - building a dedicated disc grinder is a wise decision.

 

[JV Knives]

I looked at VFDs & 3 phase motors. I might as well buy/build a purpose built disc sander.

That’s the common path.