New motor for my SB 13" lathe

[Technical Ted]

My project list for my new to me South Bend 13" lathe is getting a lot shorter!

I just recently got this lathe and it came with its' original Reliance 2HP 3-phase 230 volt motor. That motor, for some reason, just didn't like running on a VFD. It made a lot of the typical VFD motor whining like some do and also would do a little growling at times. Here's the kicker... the input amperage on the 220 volt single phase side was around 3.5 amps per leg. But, the output current (at the same voltage and running at 60 Hz) was around 9.5 amps per leg! The motor would get extremely hot after running it for a while and so I contacted FactoryMation tech support since that is where I got the VFD.

He didn't have too much to offer other than checking a few things out and said that one possibility was harmonics. I swapped out the VFD with the one off my Bridgeport (which was running fine; same HP as the lathe's motor) and the problem stayed with the motor and didn't move to the Bridgeport. Clearing the VFD as the problem, I decided to buy a new motor. Now, there are more 3 phase motors available than you can shake a stick at with prices all over the map. But, after doing some research I bought this guy:

Siemens 1LE21111AB414AA3 2-HP 230/460 volt inverter duty motor. It's a Simotics General Purpose NEMA premium type GP100A with an aluminum body/frame and copper rotor; high efficiency, fully enclosed, fan cooled TEFC.

No whine at all. At no load, draws less than 2 amps even when down to 24 Hz. Time will tell, but right now seems to be a winner!

Ted

 

[markba633csi]

Looks like a winner to me! Much more efficient than the old one I'm sure
Mark

 

[Janderso]

Hey Ted, you mentioned your old motor made a growling noise from time to time.
My 13” SB had a new motor when I bought it. Most of the time ir starts up quiet and smooth as glass. Every once and a while I flip the switch and there is this god awful loud noise, like a harmonic resonance.
I shut it off immediately, the motor is spinning while it makes the noise.
I start it up again and all is well.
Any ideas?
I am very limited with electric motors. 220 single phase.

 

[Technical Ted]

Hey Ted, you mentioned your old motor made a growling noise from time to time.
My 13” SB had a new motor when I bought it. Most of the time ir starts up quiet and smooth as glass. Every once and a while I flip the switch and there is this god awful loud noise, like a harmonic resonance.
I shut it off immediately, the motor is spinning while it makes the noise.
I start it up again and all is well.
Any ideas?
I am very limited with electric motors. 220 single phase.

You said 220 single phase. Is your motor single phase? The motor I was referring to was a 3 phase motor; horse of a different color.

There are different types of growls... if it sounds electrical and single phase it could be your starting switch hanging up, a starting capacitor, or maybe a run capacitor. That's pretty much all that's there except the windings and if they were bad I don't think it would be intermittent. Or, it could be a mechanical growl. Bad bearing or bad bearing in your cone pulley for the flat belt. Or maybe something is rubbing someplace?

If you heard the growling after cutting power then it's not electrical. I'm not 100% clear on what you are describing.

Ted

 

[Bamban]

Ted,

Where did you mount the VFD control boxes for your SBL13. Do you have a thread on your VFD installation?

I have all the parts to convert mine, just waiting to heal up from a total knee replacement before I'll tackle the project.

 

[Technical Ted]

Ted,

Where did you mount the VFD control boxes for your SBL13. Do you have a thread on your VFD installation?

I have all the parts to convert mine, just waiting to heal up from a total knee replacement before I'll tackle the project.

My SB came with an arm that had the original push buttons on it. I bent up a piece of sheet steel to replace the original cover, drilled a couple of holes in it and used that. I'm only using a on/off toggle and speed pot. I don't run my machines backwards because of the screw on chucks. But, even if I do want to, I can reverse it via the VFD front panel. You can see it in the picture right below the lamp (still needs to be painted). My VFD mount is temporary. I need to run additional 220 and 110 outlet lines into my machine shop area for the recent additions I've made over the fall/winter/spring. Currently, I'm sharing one disconnect between my two lathes which are end to end. So, for right now I just mounted the VFD on the wall up on the left hand side of the lathe. You can see the cables going up to it in the picture. I put it over far enough so nothing would fly into it off the chuck. I actually like it where it is and may leave it there and add some type of a guard to fully protect it.

Ted

 

[Bamban]

Ted,

Thank you, appreciate the info.

Nez