Usage:
3304, 3306, 3406, 3408, 3412 Packaged Generator Sets Equipped With SR4 Generators And Type 3 Or Type 4 Control Panels
- SUPPLEMENT: 01/18/84
ENGINE NEWS, OCTOBER 26, 1983, PAGE 1.
In the article, "Modification Of Control Panel Gives Different Power Source ...", the schematic and the modification are not correct. Put a mark through the article, and make a reference to the article in this issue that has the same title.
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The above units are equipped with automatic start/stop systems. The units are built to start when there is a load demand, to pick up the load, to supply power to the load and to shut down after the load has been removed. This is done without an operator.
There have been reports of failures of the starter motors on these engines. Some of these failures were caused by burned-out run relays and burned-out circuit paths to the run relays. When the run relay or the circuit path to the relay is burned out, no power is supplied to the overcrank timer. This permits the starter motor to remain engaged after the generator set engine is running. The result is a failure of the starter motor.
The new control panels are wired differently to prevent this type of problem. See the November 10, 1982 Engine News article, "Improvements To Generator-Mounted Control Panels," and the August 25, 1982 Engine News article, "New Time Delay Conversion Groups Available." If desired, a modification can be made to the control panel to supply power to the overcrank timer each time the starter motor is activated. This modification will supply power to the overcrank timer even if the run relay or the circuit path is burned out. The overcrank timer will then disengage the starter motor after 30 seconds. This will prevent damage to the starter motor caused by the starter running with the engine, or by the starter motor burning out if the engine doesn't start.
To make the modification, use a jumper wire to connect the No. 9 pin for the No. 3 contact on the arming relay to the No. 32 terminal on the control panel terminal strip. Then, break the circuit as shown in the illustration.
Locations of terminals, pins and the circuit which must be broken.