[ARC5] BC-348 Dynamotor

[J Mcvey]

I really sounds likes an overload-even with the base lead disconnected. The motor must be working very hard to turn the dyno. Have you replaced or disconnected the cap at the brush connections? Are the brushes OK?
What is the DC current draw on the LV side while "idling"? it should be much lass than the rated current. If memory serves, I had a TX dyno that was rated at 12A loaded but idled around 3 amps.You might try lokking at it with a scope. There should be some substantial noise, but floating around the DC level. My bad dyno had something that looked like raw half wave rectified DC .Perhaps there is a winding that is shorted to the armature body?
Don't know, just throwing stuff at the wall to see if it sticks...

 

    On Saturday, January 2, 2016 4:53 PM, Mark McKeown <mmckeown at tde.com> wrote:
 

  I appreciate all the suggestions.  I have replaced (restuffed all the caps in the base of the dynamotor assembly so it shouldn't be the caps.  I am running the unit on the bench using a 24 volt supply.  The supply is regulated and isn't pulled down by the dynamotor.  A vibratach says the unit is running at 5000 rpm which may be reasonable although higher than specified.  The armature gets hot with the brushes out of the high voltage end but you can still touch it.  With the brushes in I get 103 volts out instead of the 226 or so specified.  The entire unit gets too hot to touch when the high voltage section has the brushes in it.  I disconnected the hot leads from the dynamotor to the base wiring and still only get 103 volts.  Any more ideas?  Thanks!
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