Hello Jeff, A new armature reading from each communtator bars to the shaft should read over 20 megohms which means no communtators bars are shorted to armature shaft. As time go on, it is normal for this ohm reading from any communtator bar to armature shaft to read between 30 to 50 kohms which is cause by brush dust tracking from the front of the communtator bars down to the shaft.
You will note that the spacing between the front of the communtator bars are only separated by a mica insulation that may be only 1/8 of a inch thick. This is where the brush dust normally bridges this space. It is best to take the armature to a motor shop which can checks any open or short in any communtator segment with a growler test to determine if there is grounded coil or a armature bar shorts. If the armature shows good, it is best for them to re-vanish and bake the armature and coat the front of the communtator down and on part of the shaft. Then have the communtator turn to a micro mirror surface and under cut the communtator slots. If the armature needs rewinding, some local motor shops are not set up for dc motors, they normally sent them out to a dc shop which may cost about the same as a new one. Roland ----- Original Message ----- From: Jeff Mccabe via EV<mailto:[email protected]> To: [email protected]<mailto:[email protected]> Sent: Monday, June 23, 2014 3:26 PM Subject: [EVDL] I my ADC 9"Armature Bad ? Hello all, I ran my brushes to long and messed up my brush holder ring and need to turn my com. My question is I measured my Armature to Com. resistance before cleaning and it read 5.7 K ohm's after rinsing and backing out for several hours it read 17.5 K ohm's . Is it any good, or is it time for a new Armature ? Thanks, Jeff -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140623/482a20e8/attachment.htm<http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140623/482a20e8/attachment.htm>> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub<http://www.evdl.org/help/index.html#usub> http://lists.evdl.org/listinfo.cgi/ev-evdl.org<http://lists.evdl.org/listinfo.cgi/ev-evdl.org> For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA<http://groups.yahoo.com/group/NEDRA>) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140623/ccff3535/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
