Earthed circuit test
To determine if the armature windings are earthed, make the Connections as indicated in the illustration (Fig. 9). If the voltmeter indicates any voltage, the armature windings are earthed to the frame.
Field Tests (Refer to Figs. 10 and 11)
Only two tests are necessary for checking the field. Both open and short circuits can be tested in one opera-tion. The second test is for an earthed circuit.
|
Open or short circuit test:
Disconnect the field lead from the generator terminal. Connect a zero to 5 ammeter from the battery to the field terminal as shown In the Illustration (Fig. 10). The normal current draw, as indicated by the ammeter, should be 1.5 to 1.6 amperes. If there is little or no current flow, the field has a high resistance, or as open. A current flow, considerably higher than that specified, indicates shorted or earthed turns.
Earthed circuit test:
Remove the earth terminal stud from the generator frame. Make the voltmeter and battery connections as shown in Fig. 11. If the voltmeter indicates any voltage, the field coils are earthed.
Note—Ensure that the earth terminal stud is not contacting the housing.
|
**
