737 MAX Flight Crew Operations Manual
Electrical -
System Description
6.20.6
MN-FLT-OH-201
The generator drive (DRIVE) amber caution light is illuminated when low oil
pressure is sensed in the IDG. IDG low oil pressure is caused by one of the
following:
• IDG failure
• engine shutdown
• IDG automatic disconnect due to high oil temperature
• IDG disconnected through generator drive DISCONNECT switch.
A generator drive disconnect switch is installed. This switch disconnects the
generator from the engine in the event of a generator drive malfunction.
Reactivation of the generator may be accomplished only on the ground by
maintenance personnel.
AC Voltmeter, Ammeter and Frequency Meter
AC voltage and frequency may be read on the AC voltmeter and frequency meter
for standby power, ground power, generator No. 1, APU generator, generator No.
2 and the static inverter. Frequency is indicated only when the generator is
electrically excited. The voltage regulator automatically controls the generator
output voltage.
Current readings for the two engine IDGs and the APU generator may be read on
the AC ammeter.
The TEST position is used by maintenance and connects the voltage and
frequency meter to the power systems test module for selection of additional
reading points.
DC Voltmeter and Ammeter
DC voltage and amperage may be read on the DC voltmeter and ammeter for the
battery and each of the three TRs. The standby power and battery bus displays
only DC voltage.
The TEST position is used by maintenance.
March 1, 2021
