Motor Whistles When Connected to VFD

S

Steve H. Graham

Aluminum

Joined

Nov 6, 2007

Location

Miami

• Apr 30, 2009

• #1

I just received a used 3-phase motor to replace the 1-phase job on a used lathe I just bought. The lathe is a Clausing 5936. The seller was supposed to send a 5914 with a 2 HP 3-phase motor, but he sent a 5936, which was 1.5 HP and 1-phase.

I hooked the motor up to my Hitachi VFD, without installing the motor in the lathe. It runs, but it makes a whistling sound that is extremely annoying. The whistling seems to drop as I go above 60 Hz.

Is it possible this could be caused by the VFD? The faceplate on this old motor is partially illegible, so I can't be positive about all the specs. I'm told it's a Reuland motor. It's dual voltage. I have it wired up with wires 1 & 7 as L1, wires 2 & 8 as L2, and wires 3 & 9 as L3. The remaining wires are capped together.

UPDATE: Solved it. I had to reprogram the VFD and increase the carrier frequency.

 

The real Leigh

Diamond

Joined

Nov 23, 2005

Location

Maryland

• Apr 30, 2009

• #2

VFD whine is a common problem. You might run a search using that term.

Lots of opinions as to the exact source and cause of the problem.

It usually changes with motor speed/VFD frequency.

And of course different people have different audio sensitivities.

Some folks would call hard rock irritating, while others would describe chamber music the same way.

- Leigh

 

S

Steve H. Graham

Aluminum

Joined

Nov 6, 2007

Location

Miami

• Apr 30, 2009

• #3

So you're saying my post is a VFD whine. I guess that's accurate.

This motor will work, but I am really tempted to get a new Baldor and turn this one into an artificial reef.

 

P

PeteM

Diamond

Joined

Jan 15, 2002

Location

West Coast, USA

• Apr 30, 2009

• #4

Sometimes changing the carrier frequency drops the intensity of the whine. Getting through a somewhat dense and incomprehensible VFD manual is a sort of rite of passage -- it's in there somewhere and would be worth a try before you spring for a new motor. If you can get the frequency above the audible range, or at least avoiding resonance in the windings, that can help. Drawback is a greater possibility of heating up the windings. Good news for those of us getting on in age, is that our ears get less and less annoyed by high frequencies.

Oops -- you've already figured that out.

 

Last edited: Apr 30, 2009

The real Leigh

Diamond

Joined

Nov 23, 2005

Location

Maryland

• Apr 30, 2009

• #5

Steve H. Graham said:

This motor will work, but I am really tempted to get a new Baldor and turn this one into an artificial reef.

Click to expand...

A different motor might or might not provide a solution. The whine may be coming from the VFD itself, or from the motor, or both.

And re the reef... you risk getting the EPA and the local fish mad at you.

- Leigh

 

S

Steve H. Graham

Aluminum

Joined

Nov 6, 2007

Location

Miami

• Apr 30, 2009

• #6

The whine isn't what concerns me now. I'm bummed out by the lumpy rotation.

Fish love junk. Down here they sink old airplanes and ships, and the fish make themselves right at home.

 

A

atomarc

Diamond

Joined

Mar 16, 2009

Location

Eureka, CA

• Apr 30, 2009

• #7

Steve H. Graham,

It should be very smooth through the entire range. I wonder if you have all the boost and hz/frq settings adjusted properly for the load and the motor you have.

Stuart

 

S

Steve H. Graham

Aluminum

Joined

Nov 6, 2007

Location

Miami

• Apr 30, 2009

• #8

"Boost"? "Load"? Why, of COURSE those things are set correctly.

Where is that manual...

 

S

Steve H. Graham

Aluminum

Joined

Nov 6, 2007

Location

Miami

• Apr 30, 2009

• #9

Wait, you mean the rough rotation? I'm pretty sure that's mechanical. I'll bet it makes that noise if I rotate it by hand.

 

JST

Diamond

Joined

Jun 16, 2001

Location

St Louis

• Apr 30, 2009

• #10

Noisy VFDs may be in that area of their overcurrent protection that does not yet shut them down...... Normally they are reasonably silent, or there is a faint whine.

Loud noise tends to indicate a problem. Dropping above 60 Hz can support that idea....... motor current tends to drop at higher frequencies.

Look for a display indication that the VFD might be hitting overcurrent on peaks...... there is usually an indication.

Check that the VFD current setting agrees with the motor rating.

Make sure the motor is set to correct voltage, and that "motor rated voltage" and teh other basic parameters are correct.

Check that the display is correct...... some allow display of Hz, RPM, and otehr things, and may even have a multiplier factor for pole count, etc.

Other than that, raise the carrier frequency. Usually you have a choice of at least a couple.

 

P

Pierce Butler

Hot Rolled

Joined

Jun 28, 2007

Location

Texas

• May 3, 2009

• #11

Steve H. Graham said:

The whine isn't what concerns me now. I'm bummed out by the lumpy rotation.

Click to expand...

at what RPM/HZ?