GRUMMAN AMERICAN
FOR TRAINING USE ONLY – SECTION 7
MODEL GA‐7/COUGAR
AIRPLANE & SYSTEMS DESCRIPTIONS
7‐27
Issued: April 10, 1978
ELECTRICAL SYSTEM (Figure 7‐12)
Electrical power is supplied by a 14‐volt, direct current, negative ground electrical system. A 12‐volt, 25 ampere
hour battery is incorporated in the system to furnish power for starting and as a reserve power source in case of
alternator failure. The battery is located in the nose section of the airplane on the right side below the baggage
compartment floor. The electrical generating system consists of two engine driven, (self‐exciting) 60 ampere
alternators. Two solid state regulators maintain effective alternator load sharing while regulating the system bus
voltage at 14.0 volts. Also, incorporated in the system are overvoltage relays, one for each alternator circuit,
which prevents damage to electrical and avionic equipment in case of regulator malfunction. A warning light on
the instrument panel will illuminate if either alternator fails to produce current, accompanied by a zero indication
on the individual ammeter. The loads from the electrical bus system are protected by manual reset type circuit
breakers, mounted on the lower right‐hand portion of the instrument panel. An external power receptacle is
available as optional equipment, to supplement the battery system for starting the engines and for ground
operation. Operation of the battery is controlled by a master switch, located on the lower left‐hand section of the
instrument panel. The master switch also connects the bus bar to the alternator field circuit switches on the
instrument panel.
