Lincoln Electric MASTER LOAD IM575 - Manual (Page 16)

8 TROUBLESHOOTING & REPAIR 8
MASTER LOAD 750
Observe all Safety Guidelines detailed throughout this manual
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric
Service Department for technical troubleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353.
CAUTION
PROBLEMS
(SYMPTOMS)
POSSIBLE CAUSES/REMEDIES
3. BLOWER OVER TEMPERATURE
indicator lights are on, but the
blower is operating.
4. Fan blade is broken or not turning.
5. Load step(s) cannot be energized.
a. Airflow restrictions present at load bank intake or exhaust.
b. Maximum rating of the load bank may have been exceeded.
a. Fan blade motion may be obstructed.
b. Fan blade may be loose at hub or is not keyed properly.
a. Check to see if over temperature indicator is lit. (See problem 3.)
b. A blower failure may exist. (See problem 2.)
c. Master load switch may be faulty.
d. Control power may be inadequate.
e. Fuse may be blown in load bank control circuit. (Check and replace as
required).1.
f. Load step switch may be faulty.
g. Load step contactor may be inoperative.
h. Load step resistor may be open.
i. Output polarity connection is incorrect. Verify correct polarity connection
to the load bank.
1. When checking fuses for continuity, be sure to remove all fuses from clips (in fuse block or disconnect switch).
Test each fuse individually, out of circuit.