Lytebox1
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.
Normal indications are:
- AC voltmeter – 115 +/- 5volts
- Frequency meter – 400 CPS +/- 10 CPS.
Note: Normal AC voltmeter indication for the APU generator with the AC busses
loaded: 110 - 125 volts.
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. Normal indication is 26 +/- 4 volts. During primary
charge cycle operation battery voltage can be as high as 30 +/- 3 volts.
The TEST position is used by maintenance.