TM 11-6625-680-15
assembly to furnish mounting service for three 1.0
1-4 Description
KW resistors used to supply an electrical load for
1-5. The tester, consisting of three major assem-
an attached inverter-under-test. Heat buildup
blies and seven cable assemblies, is illustrated in
within the load bank assembly is dissipated by
means of convection ventilating holes cut into the
(1) that affords enclosure protection to the load
top and back of the back cover (1)
bank assembly (2) and cabinet assembly (3), which
houses the seven cable assemblies (4) and mounts
the panel assembly (5).
1-10. Direct current power source of 28 VDC at
5-KW rating is required by the tester for test of all
1-6. Panel Assembly. The panel assembly
aircraft inverters up to and limited at maximum
output of 2500 volt-amperes.
exception of autotransformer and load bank, and
displays all controls, meters, indicators, and
terminals controlling the operation and testing
1-12. The Type L-1A tester is designed to test any
facilities of the tester. The controls and meters
consist of: A.C. AMP RANGE selector (21), A.C.
aircraft inverter, whether single-phase or three-
phase delta output, limited to 2500 volt-amperes.
PHASE selector (19), A.C. PHASE switch (18)
Provisions are incorporated to perform test
LOAD switch (13), LIVE CIRCUIT switch (16),
procedures by plugging a designated cable assem-
D.C. PWR switch (12A), D.C. AMP RANGE rotary
bly (paragraph 4-3); into the tester connector
shunt selector and start switch (12), and LOAD
CONTROL autotransformer selector (17); the five
and connecting the cable assembly to the
meters include A.C. AMPS. meter (2), A.C. VOLTS
inverter-under-test.
meter (4), FREQUENCY meter (6), D.C. AMPS
1-13. The inverter is activated by DC-power
meter (8), and D.C. VOLTS meter (10). Indicator
applied by the tester to the inverter input section
lights displayed are red 5A indicator fuse (9) and
by means of the interconnecting cable assembly.
green 28V. ON indicator (1) Fuses displayed are
Inverter output is returned to the tester through
5A (3) and 1/16A (5, 7, 11). Cable assembly
the same cable assembly.
connector (22), tester name plate (20), and power
1-14. Inverter input voltage and current, supplied
terminals +28V (14) and --DC (15) complete the
by the tester, are indicated for recording by the DC
panel assembly configuration.
1-7. Cabinet Assembly. The cabinet assembly
inverter: amperage, voltage, and frequency are
indicated for recording by the AC ammeter, AC
mounts the autotransformer (6), and encloses the
internal components and circuits of the tester
1-15. Variable electrical load is imposed on
attached to the panel assembly (5) A recessed
the inverter by routing current through the
portion within the cabinet top provides storage for
tester load bank, with variable load control
the seven cable assemblies (4) used in forming
settings providing the limits.
external tester-inverter connections.
1-8. Load Bank Assembly. The load bank
filament or cathode heaters of electronic tubes
used in control
assembly (2) is attached to the rear of the cabinet
1-2 Change 1
