3 Phase, 9 lead, 6 contactors control motor not running

[nmark]

I have a few details 480volt, 3phase, 9 lead motor with all nine leads terminating at 3 contactors.
DOL line starting energizes 2 contactors
they time out/drop out and 2 contactors accelerate motor after motor reaches speed 2 contactors close running motor at speed.
I have been told motor start contactors (2) close but motor does not spin. There is no mechanical load on it/belt is disconnected and motor shaft can be spun by hand.
I will be going to jobsite tomorrow to investigate further.
If anyone has experience with starting method mentioned above I am all ears.
Thanks in advance for any replies.

 

[waross]

It sounds like it may be a consequent pole two speed motor. There may be blown fuses. Check to see if you have voltage going in to the contactors and coming out of the contactors.
Check for continuity between the motor leads.
respectfully

 

[Skogsgurra]

Hi,

This is a two-speed motor? Isn't it?

A similar problem was discussed to some depth in

http://www.eng-tips.com/viewthread.cfm?qid=139661&page=1

There are links and a list showing speed vs contactor activation.

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[nmark]

Hello,
Voltage was o.k but when checking continuity I found 2 motor leads that were terminated at starter panel reversed .
On the bright side I am able to get motor to spin when start button is pushed but only the first 2 contactors close (Starting) the prox that is detecting rpm is bad.Controller needs to see minimum rpm before engaging accelerating contactors. Tomorrow I should have new proximity switch installed and hopefully I will be able to put this job in the memory hole. I did have a diagram of the 6 contactors used for starting/accelerating/running the motor to upload but my computer skills are lacking.
Thanks

 

[oftenlost]

Is this a dual voltage, single speed motor? I have seen motors with 9 leads, single voltage set up for single/parallel delta or wye connections. If it is single speed, single voltage set up for soft start, it could be wye or delta. Check for continuity between 7,8, and 9. If you have continuity between these three,Then check for continuity between any of those and lead 1 for example. If this is open then you have a 1 Y start, 2 y run machine.(10,11, and 12 are connected internally)
If 7,8 and 9 do not light out, check for continuity between 1,4 and 9. If you have continuity there, check any of them to 7 for example. If this is open, you have a 1 delta start, two delta run with 1-12, 2-10, 3-11 connected internally.
There are not a lot of these out there but they are there. They are basically two voltage motors with the low voltage being 460.

 

[electricuwe]

Nine leads would match to a three-speed motor intended for Dahlander connection. But in this case four contactors would be necessary. Three to connect windings to the line and one to close the star point.

By the way, you post has contradicting information on the no, of contactors used:

Headline: 6
Post: 3

I could cite a german book for reference, but I'm afraid that won't be helpful.

 

[nmark]

Thanks electricuwe the devil is in the details. The nine motor leads terminate at 3 terminal blocks in control panel. The six contactors control the motor.
C3(contactor)C5 STARTING
C4,C6 ACCELERATING
C1,C5,C6 RUNNING
C3,C5 BRAKING
Motor leads continuity below.
T7-T8-T9.
T1-T4.
T3-T6.
T2-T5.
The motor has a single voltage rating.
480volt
Y YY
30A/93A.
I was not able to install new prox for motor speed today. I still have not seen motor move beyond starting stage.