Reading Armature Current with a Clamp On Amp Meter
Reading Armature Current with a Clamp On Amp Meter
(OP)
I have read Armature Current with a Clamp On Amp Meter many times on AC and DC Motors. However on DC Motors I have generally read a lead to see if it looked normal. Recently I had a 7.5hp DC Motor that seemed hot when I shot it with a Pyro, 167 F. I then checked the Armature leads at the Drive with a DC Clamp On Amp Meter, Results
A1=.3A, A2=3.3A, both leads together in the Clamp=1.6A.
Can anyone explain to me the readings? I do not understand how this readings separately are so different than when read together.
A1=.3A, A2=3.3A, both leads together in the Clamp=1.6A.
Can anyone explain to me the readings? I do not understand how this readings separately are so different than when read together.





RE: Reading Armature Current with a Clamp On Amp Meter
I expect your Hall effect meter is effected by the nearby field poles, but just to be sure check for a ground fault on the armature.
Try flipping your meter over so the wire goes through the other way, you might find the +/- are different.
Roy
RE: Reading Armature Current with a Clamp On Amp Meter
The only leads at the bottom of the Drive were the Armature leads, no other wiring close.
RE: Reading Armature Current with a Clamp On Amp Meter
It couldn't be one of the excitation wires you measure on?
.3 A seems to be in the right ballpark.
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Reading Armature Current with a Clamp On Amp Meter
I think Skogs is onto something.
Roy
RE: Reading Armature Current with a Clamp On Amp Meter
RE: Reading Armature Current with a Clamp On Amp Meter
RE: Reading Armature Current with a Clamp On Amp Meter
RE: Reading Armature Current with a Clamp On Amp Meter
The sparking at the brushes is causing very large current to ground?
Is there any ground protection or indication associated with this motor or supply?
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Reading Armature Current with a Clamp On Amp Meter
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Reading Armature Current with a Clamp On Amp Meter
By bad commutator, do you mean mechanically bad (grooves, worn-out etc.) or electrically bad (Ground fault though it could be the winding too) ?
Also, you cannot just replace the commutator alone. It is either a rewind with new comm or a new rotor altogether - both of them have a considerable lead time.
RE: Reading Armature Current with a Clamp On Amp Meter