Generator Description and Operation P72

The P72 chassis uses a Delco-Remy model CS-130 generator. This unit has an integral regulator but does not have a diode trio. The delta stator, the rectifier bridge, the rotor with slip rings and the brushes are electrically similar to other CS-series generators. It uses a multi-groove pulley. An internal fan cools the slip rings, the end frame, the rectifier bridge and the regulator.

The charging indicator activates when the engine control switch is closed. It goes out when the engine is running. If the charge indicator is on with the engine running, a charging system problem is indicated. The indicator will glow at full brilliance if any charging problem occurs or the system voltage is too high or too low.

The regulator voltage setting varies with the temperature and limits system voltage by controlling the rotor field current. It switches the rotor field current on and off at a fixed frequency of about 400 cycles per second. By varying the "on-off" time, the correct average field current for proper system voltage control is obtained. At high speeds, "on" time may be 10% and "off" time may be 90%. At low speeds, with high electrical loads, "on-off" time may be 90% and 10% respectively.

The regulator has four terminals, "P," "L," "I" and "S". The "S" terminal monitors the battery voltage so that the regulator can maintain an adequate voltage output. The "I" terminal senses when the engine control switch is in RUN, turns on the regulator and allows field current to flow. The "L" terminal is wired through the charging indicator lamp and senses when the engine control switch is in RUN or the "crank" position. The "P" terminal provides a timing pulse for engine start up to the alarm module.

No periodic maintenance or adjustments are required on the generator. It is serviceable by replacement only. It should not be disassembled for any reason.

Generator Description and Operation P92

The P92 generator is manufactured by Leece-Neville. The model 4884JB is a 200 amp, air-cooled, belt-driven unit that is designed for heavy-duty diesel engine applications.

This unit features an integral voltage regulator, fully-enclosed brushes, built-in rectifier assemblies with extra large heat sinks, a dynamically balanced rotor and a heavy-duty stator and bearings. It has extended one-quarter inch AC terminals that are provided for accessories, such as converters, power packs, etc.

The alternator has an extra terminal (marked TO #1 TERM. OF DUVAC®) for used with DUVAC® and battery isolator systems. The DUVAC® terminal is internally connected to the regulator positive terminal. This connection allows the regulator to monitor output voltage and provides a source of current for field excitation.

The integral voltage regulator is accessible without removing or disconnecting the unit and is fully adjustable. No other maintenance or adjustments are required on this generator. Except for adjusting the voltage regulator, it is serviceable by replacement only.