TM 55-1930-209-14&P-2 Table 4-1.  Seawater Discharge Pump and Cooling Pump Troubleshooting (Cont'd) Problem Probable Cause Suggested Action 5. Motor   runs   too   fast   under load a. Line voltage is too high a. Check   line   voltage   (paragraph   4-7.2.6.2 for seawater discharge pump or paragraph 4-7.2.7.2 for cooling pump) 6. Motor  fails  to  start  but  gives a loud hum a. One of the phases to motor is not energized a. Check   thermal   overload   units   in   motor controller and replace if necessary. Check cable continuity to motor (paragraph 4-7.2.6.2 for seawater discharge pump or paragraph 4-7.2.7.2 for cooling pump) Table 4-2.  Cooling Pump Motor Controller Troubleshooting Problem Probable Cause Suggested Action 1. Motor controller fails to operate a. Motor controller is malfunctioning a. Visually check for signs of heat, smoke, or smell    of    burning    insulation.        Replace damaged part or repair as given in step 4 b. Bad fuse b. Replace fuse 2. Motor controller fails to start motor after pressing START button    and    overload    rely reset button a. If   system   remains   dead,   motor controller at fault a. Check motor controller (paragraph 4-7.2.7.2) relay reset button b. If    power    contacts    close    power circuit at fault b. Check  power  circuit  to  motor  (paragraph 4-7.2.7.2) c. If motor fails to start and give 3. Contacts chatter a. Poor contact in control relay a. Clean relay contact 4. Overheated contacts a. Dirty contact tips a. Clean relay contacts b. Loose connections b. Clean and tighten 5. Noisy magnet a. Broken coil a. Replace b. Dirt or rust on magnet b. Clean c. Low voltage c. Check    system    voltage    and    correct    if wrong 6. Magnet failure to drop out a. Gummy    substance    on    magnet faces a. Clean with approved solvent 4-3