Section 5. Troubleshooting
Model 6210 Maintenance Manual
DC Electric Motor
Short-Circuited Winding A short-circuited winding is one where the insulation on the field or armature has broken down at two or more points. The breakdown creates a low resistance path, permitting current to flow from one turn of the coil to another adjacent coil turn, without actually flowing through the coil wire. The result is a decrease in total resistance of the motor winding and an increase in the current flow. The severity of the short circuit depends on its location. A shorted motor may be indicated by: •
Slow or sluggish operation
•
Running faster than normal
•
Overheating
•
Blowing a power fuse
•
Severe burning or discoloration on one or two commutator segments every 90° of rotation
These symptoms can also be caused by problems other than the motor itself, such as: •
Brake too tight or dragging
•
Wheel bearings too tight
•
Faulty transmission
•
Binding in an attached pump
Testing a motor for short-circuited windings requires special equipment at a motor rebuilding facility.
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Publication: 1146947, Revised: 12 Jan 2017
