TM9-4120-400-14
4-40.
TRANSFORMER T1. - continued
INSPECTION
Check transformer for general condition, signs of overheating, and loose, missing, or broken terminals.
TESTING
1.
Remove four screws (1), lock washers (2), and flat washers (3) and pull transformer (4) from unit.
2.
On 3 phase units only. Tag and disconnect leads from terminals 2 and 7. Check for continuity across the
primary winding pin 2 to pin 5 and across the secondary winding pin 7 to pin 8. If either winding is open,
replace transformer. (See para 4-20.)
3.
On single phase units only. Tag and disconnect leads from terminals 1 and 7. Check for continuity across the
primary winding pin 1 to pin 3 and pin 4 to pin 6 and across the secondary winding pin 7 to pin 8. If either
winding is open, replace transformer. (See para 4-20.)
4.
Check for shorts between one terminal of each winding and transformer case and also between one primary
terminal and one secondary terminal using a multimeter on high ohms setting. Replace transformer if a short is
indicated.
5.
See wiring diagram figure 4-4 and tags and connect all wire leads. Remove tags. (See para 4-20.)
6. Attach transformer (4) to unit with four screws (1), lock washers (2), and flat washers (3).
REPLACEMENT
1. Remove four screws (1), Iock washers (2), and flat washers (3) and pull transformer (4) from unit.
2. Tag and disconnect wire leads. (See para 4-20.)
3. See wiring diagram figure 4-4 and tags and connect all wire leads to new transformer. Remove tags.
(See para 4-20.)
4. Attach transformer (4) to unit with four screws (1), Iock washers (2), and flat washers (3).
NOTE
FOLLOW-ON MAINTENANCE:
Install junction box (para 4-27).
Install top front panel (para 4-11).
4-98
