This is a 110 Volt Reel motor armature being checked on growler. A growler is an open end transformer that induces AC power into a static armature for the purpose of checking for shorted turns.
When shorted turns are detected by the viberation of the hack saw blade you can check the commutator at approx 10 & 4 o'clock positions. Many times a small piece of copper is shorting two bars together. Clear the slot and recheck.
The volt meter shows the voltage between each bar at the 10 & 4 o'clock positions as you turn armature you can can check each bar.If you get no reading there is your short . If the bar is clear at both 10 & 4 o'clock .......you may have the short inside the winding.
One more test is check for short to ground as in ....the windings touching the body of the armature.
This can be done with 110 volt test light. (good for 6 or 12 volt units)
Sometimes an armature can be 'saved" by squeezing the laminations in a vise and rechecking for grounds or shorts. Dip the armature in insulating varnish or paint and let dry .
Some years ago some major rebuilders used to "Blow shorts " from Starter Armatures by a simple device with a handle on two probes about 3-4 inches apart that contacted the commutator & body of armature at same time with 220 volts ! It was quite a sound & light show .....the armatures that passed test were then dipped in varnish and baked. They were turned and used quite successfully in rebuilt starters.
I am located at 1991B US 501, Myrtle Beach, SC 29577. I can be reached at 843-455-8062.
