ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals

Topic Options
Rate This Topic
#198912 - 02/07/11 04:48 PM Commutator Arcing!!
williams Offline
New Member
Registered: 01/11/11
Posts: 6
Loc: canada
What I have is an old Rigid Pipe Threader unit 535 series. My original problem with this was that it was tripping the breaker. After doing a few quick checks and found nothing really wrong I took the motor out to find the Stator windings had arced and had a short. Thinking this was the problem I ordered a new field, bearings, brushes and brush wires would solve this issue. After reinstalling the motor to give her a try there was some sparking going on the commutator between the brushes and then 10 seconds later a tripped breaker. Now this obviously is now pointing to the armature and com but is there any thing I can do for testing before I order a new one or at least learn something for the next time.
Thanks
Top
Tools for Electricians:
#198984 - 02/09/11 03:26 PM Re: Commutator Arcing!! [Re: williams]
williams Offline
New Member
Registered: 01/11/11
Posts: 6
Loc: canada
Ok here is what I have found. This motor is universal AC or DC and I am using 120 V AC. The first test I did was use a Ohm Meter to see if there was any continuity between the commutator and the shaft and was in fact open. Then I use a test lamp and applied 120v to the shaft and tested to each commutator bar to see if I would get a light and I did which means the insulation was broken down. The reason why the ohm test never worked was because it only applies 10VDC were the test light is 120VAC. I never used this test light before and it worked well.
Top
#198986 - 02/09/11 05:56 PM Re: Commutator Arcing!! [Re: williams]
Tesla Offline
Member
Registered: 06/16/04
Posts: 1273
Loc: Sacramento, CA
Over time the two components that wear are the brushes -- which are cheap and easy to swap -- and the commutator.

Without the trick equipment most commutators can't be 'tuned up.'

A worn commutator will just ruin new brushes in short order.
_________________________
Tesla
Top
#198993 - 02/09/11 08:40 PM Re: Commutator Arcing!! [Re: williams]
twh Offline
Member
Registered: 03/11/04
Posts: 901
Loc: Regina, Sask.
For next time, a megger is a better tool for testing a motor.
Top

Member Spotlight
Member Since: 04/03/02
Posts: 6778
New in the Gallery:
SE cable question
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box


Who's Online
0 registered (), 70 Guests and 10 Spiders online.
Key: Admin, Global Mod, Mod
 
New in the Gallery:
SE cable question
 
Top Posters (30 Days)
Admin 47
HotLine1 43
gfretwell 19
Ruben Rocha 12
Trumpy 9
 
Newest Members
Scotto, Freecrowder, clee512, Jdscott2005, FAIZAN

ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals