Figure 70Testing for Shorted Armature Coils Using Growler 4UG5940

and a pair of test prods. This is a current draw test and results will depend upon condition of battery and accuracy of the ammeter. The regulating field coil is located in the upper side of tb£ frame and is identified by an orange paint mark.

(a) Test for Open or Internal Short (fig. 72). With tester, battery and test prods correctly connected, touch the coil and terminals of the coil. Tester should register 1.4 to 1.9 amperes. If no tester reading is recorded, field coil is open. If tester reading exceeds 2.2 amperes, the coil is shorted. Replace the coil.

(h) Test for Ground. Touch one of the coil end terminals with one test prod and touch the generator frame with the other test prod. Ammeter should register "NO READING." If a reading is observed, coil is grounded to the generator frame and must be replaced.

Armature Coiling Figure

Figure 7J—Testing for Open Coils in Armature Using Growler (4I-G-5940)

RA tO 310322

Figure 7J—Testing for Open Coils in Armature Using Growler (4I-G-5940)

(c) Test Shunt Field Coil (figs. 72 and 73). Follow same procedure outlined in (2) (a) above. The shunt field coil is located in the lower side of the frame and is identified by a white paint mark. A higher resistance winding is used in the shunt coil and the normal current reading will be less. A normal coil will draw from 0.6 to 1.0 ampere. If tester reading exceeds 1.5 amperes, it is shorted within and must be replaced. Make ground test per instructions in (b) above.

(d) Test Positive Brush Holder and Terminal Posts for Ground (fig. 74). The positive brush holder and the two terminal posts are insulated from the generator frame. Touch frame with one test prod and the positive brush holder and terminal posts respectively with

Figure 72— Testing Field Coil for Open or Internal Short

0 0

Responses

Post a comment