|
Armatures can be hard to test as free from grounds, short circuits, or open coils. A simple circuit is shown.
This "growler" was made from old "autolite" generator, model GA, type DR6 off old Willys-Knight car. Cut long laminated core horseshoe legs at angle like a V- block able to accept round armature in the center with hacksaw and cover cut ends with aluminum caps or heavy fiber material able insulate from armature.
Make sure switch is OFF when placing the armature in V- opening fork of our magnet, then turn switch ON.
First test, hold hacksaw blade above armature lengthwise and almost touching and slowly rotate the armature. If metal hacksaw blade is attracted to magnet it means the coils are shorted.
Next, use 6 volt battery with test lamp and two probes. Probe on one segment of armature and move other probe to find which makes test lamp light. Hold this position and slowly move around testing other segments. If lamp fails to light the coil connecting these segments is open.
The test leads at far right is to test grounds by holding one lead on shaft and
touching segments of commutator. If the lamp lights that coil is grounded.
Note that armature may test free from faults when cool and still and centrifugal force, heat from running, cause grounds during operation.
|
