Smart questions
Smart answers
Smart people
Join Eng-Tips Forums
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Member Login




Remember Me
Forgot Password?
Join Us!

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips now!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

Join Eng-Tips
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Jobs from Indeed

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

aPojk (Industrial) (OP)
21 Sep 13 19:15
Hi All,

I have a perske router spindle:
vs60.11.2
5.5hp
220v 13.3A
17550rpm 300Hz

I had a current overload error on the VFD, so i took the motor apart and cleaned it out,
ran an insulation test on winding to ground and winding to winding also measured the
resistance on the windings to see if they were consistent. Every measurement i took checked out fine so i got new bearings and assembled the motor.
The same overload error occurred. running the motor at 6Hz, it ran but drew a current of 14A.
ran insulation test again with no faults, had the dc test voltage at 1000v. any pointers on how to proceed with this motor?

Thanks,
Frank
ScottyUK (Electrical)
21 Sep 13 21:38
Prior to the problem developing, what had been done to the motor?

If the motor measures good, then the drive may be at fault. It's an unusual drive (commonplace, but still 'different' to the majority) and without some reasonable test gear you'll probably struggle to make much progress.

Do you have a standard VFD of, say, a couple of kW available for testing purposes? You could run the spindle motor at reduced speed and frequency from a commodity drive and would perhaps isolate the problem to either the drive or the motor. You will need to adjust some of the test drive to some non-standard settings to match the high speed motor.
itsmoked (Electrical)
22 Sep 13 4:39
I think Scotty makes good sense.

I find with machine tools it's just about %50 of the time the VFD and %50 the motor. So it's very possibly the VFD.

Keith Cress
kcress - http://www.flaminsystems.com

aPojk (Industrial) (OP)
22 Sep 13 4:58
i got the complete router quite cheap(or so i thought) since the control system was outdated. I installed a new control system and thought i was done. That was when i saw the VFD was broken. I bought a new VFD from our usual supplier of such things, an Omron JX 5.5Kw. So now it looks like the motor is having some issues too, but i can't seem to let the motor go as long as i can't measure anything wrong with it.
The rotor's not in mint condition, but i've never seen rotors causing behaviour like this.
Helpful Member!  ScottyUK (Electrical)
23 Sep 13 1:43
What is the base frequency your new inverter is set to, i.e. at what frequency will it reach full output voltage?

In their default state most drives - other than exotic stuff like dedicated spindle drives - will reach full output volts at either 50Hz or 60Hz depending on where you are in the world. Your motor is expecting full volts at 300Hz. If this config error exists then the net effect would be that the motor is getting either 5x or 6x the voltage it is designed at those low frequencies, which would explain the overcurrent.
LionelHutz (Electrical)
23 Sep 13 8:54
I agree with Scotty, saw the problem as soon as I saw that 17550rpm, 300Hz data. Set the base frequency or motor rated frequency to 300Hz. Make sure the motor rated voltage is set to 220V at the same time.
aPojk (Industrial) (OP)
23 Sep 13 14:43
Thanks!

Most all motors i deal with are 50hz 220v, so the base frequency didn't cross my mind(though admittedly it should have after the initial problems), with the new inverter(correctly set up) and bearings this motor is now running smooth and silent.

Frank
ScottyUK (Electrical)
23 Sep 13 14:50
Thanks for the update Frank - pleased your machine is running properly. smile

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close