Fuse Blows near last point multiple:
- No. 2 motor grounded.
- Either armature short-circuited.
The fact that the fuse did not blow on the series positions excludes the resistances and No. 1 motor from investigations for grounds.
Cut out both motors. If the ground still exists the controller is defective. If not, the fault may be located in either one of the motors by cutting out first one and then the other.
ARMATURE TESTS FOR GROUNDS.
With a lamp bank at hand tests for grounded armature can be made as follows:
Throw the reverse on center. Attach one terminal of the lamp bank to the trolley. Put the other terminal on the commutator of the armature to be tested. No current shows the armature O. K. If current flows remove brushes and try again, to be certain that the ground is not in the leads.
FIELD TESTS FOR GROUNDS.
Disconnect field leads and put test point of the lamp bank on one side of the terminals. No current indicates that the fields are O. K.