One of our recent customers had a small scare with their new generator. Nothing dramatic, just puzzling. The engine started normally and everything seemed 100%, except for one issue: no electricity was being generated to the main terminals or the convenience outlet. Frustrating to say the least.
The customer and GMG tried most of the common checks with no affect. Here were the symptoms:
- Engine ran fine
- No electricity at convenience outlet
- No electricity at terminals
- Nothing on the Hz/frequency or Voltage meter
Our customer was patient with our requests to double-check common items such as:
- Making sure the master phase selector switch was in the 110/220 volt position (3 o’clock)
- Making sure the master breaker was on
- Making sure the small breaker for the convenience outlet was on (pushed in)
- Making sure the readout selector on the Control Panel was set to the correct setting (single phase, 110/220 volt). This MUST match the Phase Selector Switch. You can play with this while the unit is running. You would want the voltage meter to read 240 volt and the frequency meter to read 60 Hz (corresponding to an engine speed of 1800 rpms).
Still nothing! Ugh! Our incredibly resourceful customer did a quick Google search and found that these symptoms are associated with a non-energized electrical field in the generator head (windings). While the unit was running, but not generating electricity, he set the master switch to the “Start” position for 3 seconds to “flash/energize” the electrical field within the generator head. This worked!
We wanted to dig a little more deeply, so we provided the scenario to our technical staff. They had more color to add to what was going on. As with all military generators the Master Switch is to be held in the start position long enough to start the engine AND excite the field windings in the generator itself. The operating instructions on the side of the unit states “Move Master Switch to Start position and hold until the engine runs continuously.” Even the newer units require you to hold in the start position after the engine is running to excite the field windings. Not all generators are identical. Some excite right away. Others take a few seconds. There is an Anti-Restart switch on the engine that disengages the starter after the engine starts. No harm will come to the starter after the engine has been started and the Master Switch held in Start.
Note that this is one of the many items that our tech team tests during the refurbishment process.
So, make sure to hold the Start Switch in the start position until the engine is 100% running continuously plus a couple of seconds and you can avoid this inconvenience. Manually “flashing” or “energizing” the unit is still possible by simply holding the switch in the Start position for a couple of seconds even after the unit has been running.
Hope this helps more folks out there and reduces some blood pressures! As always, send us your questions and tips so that others can benefit! Note that the above pertains to MEP-002A and MEP-003A units, but may also pertain to other models.