What's new
What's new

Reliance Motor on SB13 - Missing a part?

mlitzkow

Plastic
Joined
Jun 16, 2021
Location
Madison
I have been refurbishing a South Bend 13 for about a year now. I have the lathe running but am not satisfied with the sound of the motor. There is a high-pitched whine that I can't hear, but it bothers the heck out of my wife as it seems to penetrate through the whole house. (I mostly can't hear this sound because of loss of high-frequency hearing, but I can record it and see it in spectral analysis.)

The motor is a Reliance (later bought out by Baldor) 2HP 3PH. I am running it with a cheap VFD from Amazon (XSY-AT1). I don't have a means of powering the motor other than through the VFD. I have taken it back out of the lathe and have it running with the VFD on my bench. I have verified that the noise comes from the motor, not the VFD or any other part of the lathe.

I originally thought the motor bearings were OK and didn't replace them. However, since I have this noise, I decided to preemptively replace them - just in case that makes a difference. When I pulled the bearings out of the motor, I discovered that one end had a spring and a plate in the bearing cup, while the other end has a spring, but no plate. Here are the parts I found:
http://www.mikelitzkow.com/wp-content/uploads/2022/01/20220114_094424.jpg

I can't find any parts diagrams or other information on this motor. Here is the data plate:
http://www.mikelitzkow.com/wp-conte...amScanner-01-14-2022-07.39-e1642178898770.jpg

My question is whether anybody knows if both bearings should have a plate associated with the spring? Maybe somebody took the motor apart before me and lost that part? Maybe the extra end-play causes the noise? Or maybe, it's time to "bite the bullet" and buy a rotary phase converter? Any and all advice on how to get rid of this noise will be appreciated.
 

dalmatiangirl61

Titanium
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
Without hearing it, my guess is its the high pitched whine that all/most vfd's make. Maybe better units don't do that, but in my experience in shops that use them, I can always hear it. I realize you say its coming from the motor, but its caused by vfd. I could be wrong, see if you can power it off real 3ph somewhere and see if its still makes the noise.

I run an rpc, not happy with the noise it makes, but will take it over the high pitched whine that bores into my brain.
 

Dobermann

Hot Rolled
Joined
Jan 2, 2014
Location
North Carolina
The sound you don't hear is likely caused by the VFD. They all contain high frequency oscillators which oscillate in the range of human hearing. If you look at the instructions for your drive you'll probably find a setting which will allow you to change the frequency of the oscillator. You can usually move the frequency higher or lower. If I recall properly, there are some performance issues associated with going to higher frequencies but you could try that or you could set it lower and perhaps your household might find a lower frequency less annoying.

The sound may be coming from the drive itself or it may be coming from vibrations set up inside the motor--either windings or laminations vibrating at the drive frequency. It's possible you could reduce the sound by putting some sort of blanket over the motor but that may interfere with cooling if you're running the motor under heavy load.
 

wood2steel

Aluminum
Joined
May 17, 2013
Location
georgia
Go for the rotary converter if you can but although we scold the static converters, i ran my tech school 1973 13" SB with Reliance 2 hp motor for 16 yrs without a glitch on a Phase-matic and it was plenty happy. PM if you want more insight regarding this setup. I have two other Industrial LATHES still running the same til I finally get my HD rotary converter up and running .
Johnny
 

4GSR

Diamond
Joined
Jan 25, 2005
Location
Victoria, Texas, USA
I have a 1 HP Reliance 3PH motor on my vertical bandsaw powered by a TEAC VFD. It does make a wine noise, its not loud but you can hear it. I would suggest you go thru all of parameters on the VFD amd make sure they are set properly. The noise should not be so loud you hear it thru out the house.
 

mlitzkow

Plastic
Joined
Jun 16, 2021
Location
Madison
Really good to know! Thank you.

Without hearing it, my guess is its the high pitched whine that all/most vfd's make. Maybe better units don't do that, but in my experience in shops that use them, I can always hear it. I realize you say its coming from the motor, but its caused by vfd. I could be wrong, see if you can power it off real 3ph somewhere and see if its still makes the noise.

I run an rpc, not happy with the noise it makes, but will take it over the high pitched whine that bores into my brain.
 

jim rozen

Diamond
Joined
Feb 26, 2004
Location
peekskill, NY
I have a 1 HP Reliance 3PH motor on my vertical bandsaw powered by a TEAC VFD. It does make a wine noise, its not loud but you can hear it. I would suggest you go thru all of parameters on the VFD amd make sure they are set properly. The noise should not be so loud you hear it thru out the house.

TEAC made drives?
 

Just a Sparky

Hot Rolled
Joined
May 2, 2020
Change the carrier frequency on the drive. Factory default is probably 4kHz. 12 or 16kHz will be less annoying.

Nicer drives can be configured to add randomness to the carrier frequency (e.g. white noise) to further quiet it down.

Or install a single phase motor.

Thermite jumping in to suggest a $2,000 DC motor and drive in 3... 2... 1...
 

Tony Quiring

Titanium
Joined
Nov 5, 2008
Location
Madera county california usa
Get a sond level app for your phone.

Many different ones.

They can show frequency and level.

Then use your phone to locate the sound that you cannot hear.

It could be the windings in the motor reacting to the carrier.

A low dollar VFD may NOT have suitable line filtering and may be causing the windings in the motor to vibrate causing the noise.

A filter may greatly reduce this noise and instalation is simple, it just goes between VFD and motor.

Other folks who do this more should be able to provide suggestions for size and type.

Sent from my SM-G781V using Tapatalk
 

jmm03

Hot Rolled
Joined
Aug 8, 2004
Location
ventura,ca.usa
I second Sparkys suggestion to try adjusting the carrier frequency parameter on the drive. there is a limit as to how much you can tune out however. Jim
 

mlitzkow

Plastic
Joined
Jun 16, 2021
Location
Madison
Followup

Those who suggested changing the VFD's carrier frequency (AKA PWM frequency) were right on track. Unfortunately, my cheap Amazon VFD was already set at 10K Hz, and that's as high as it goes. I ended up buying a better VFD that goes up to 15K Hz, and that mostly solves the problem. The whine is greatly reduced, and also has a smoother sound with less of the unpleasant "burr" created by the VFD. Unfortunately, my wife is out of the country for a couple of months, so final judgment on the sound quality will have to wait for her return. If she still doesn't like it, I'll have to go for the phase converter.

I also got some good suggestions on troubleshooting a sound that I can't hear. I was able to record the sounds on my PC using an open-source program called Audacity. Audacity supports a couple of kinds of spectrum analysis so that I could see the peaks at 10K Hz and above that represent the obnoxious noise. My before and after recordings of the spectra are pretty convincing. Also, even though I stated earlier that I can't hear the sound, that's not completely true. When I look directly at the motor, my ear canals are at a right angle to the motor, and I can't hear the whine at all. I later found that when I turn my head so that my ear canal is in a line pointing to the motor, I can hear the sound pretty well. Based on my hearing, spectral analysis, and independent confirmation from friends who do hear the sound, I think the new VFD with higher carrier frequency made a significant improvement.

Many thanks to all who sent suggestions. You guys are awesome!
 








 
Top