... 4,5,HUS-ORN,2,3,HC-3,KS-4,HS-4,HUJ-RN,KBM-600,LDU2,3,4,LDU- ... energy loss is small. (3) When carbon brush runs, no heat, noise, broken, what’s more never change color carbon ... . Bar edge must be chamfered and there should be no burned edges.Brush Holders:They must be mechanically sound and ... unit is off neutral, you may observe sparking under a no-load condition. Depending upon how far off neutral the ...