STUDENT GUIDE FOR T-1A AIRCRAFT SYSTEMS
The DC voltmeter placarded VOLTS, is located in the overhead switch panel. The voltmeter
displays the DC voltage supplied by either the right or left generator or the battery.
604. AC POWER SYSTEM
The AC power system supplies AC power required by various aircraft systems.
AC Power Components
Two inverters located in the nose compartment supply AC power.
Two static inverters, No. 1 and No. 2, supply 115 and 26 Volts Alternating Current (VAC), 400
Hz, single-phase electrical power at an apparent power rating of 250 volt-amperes each.
AC Power Distribution
AC power is distributed through three 115 and three 26 VAC buses. The AC buses are the only
sources of AC electrical power for those systems requiring supplemental AC power.
AC Power Distribution Control
An inverter selector switch is located in the main circuit breaker panel. The switch is placarded
INV SEL, with its switch positions labeled NO. 1, AUTO, and NO. 2. The switch is normally in
the guarded AUTO position. In this position, the No. 1 inverter supplies power to the primary
buses and the No. 2 inverter supplies power to the secondary buses.
Placing the inverter selector switch in the NO. 1 position forces the No. 1 inverter to power the
primary buses by bypassing their fault sensing circuits. Placing the inverter selector switch in
the NO. 2 position causes the inverters to trade functions so the No. 2 inverter powers the
primary buses and the No. 1 inverter powers the secondary buses.
An AC voltmeter is located on the aft circuit breaker panel adjacent to the rotary AC voltmeter
selector switch. The meter indicates the voltage of one of the four sources of AC power as
selected by the selector switch to confirm inverter operational status.
605. ELECTRICAL POWER SYSTEM LIMITATIONS
Refer to Instrument Markings, Section V, T.O. 1T-1A-1, for specific limitations of the various
components of the electrical power supply system.
ELECTRICAL POWER SYSTEMS