DIFFERENCES BETWEEN SERIAL NUMBERS

TM 55-1730-229-12

TO 35C2-3-473-1

(3) An aircraft (AH-64A) type,

These differences should be noted

400 Hertz to 28 VDC, transformer

prior to any maintenance or repair

rectifier unit (TRU) is used on the

actions.

83-360D to power the battery char-

ger, the 60-Hertz inverter and to

(3) Locating the CURRENT LIMIT

start or service DC aircraft. The

SELECTOR switch to the 30 KW setting

TRU is mounted to the front side of

in addition to the 45 KW setting,

the DC cable storage bay. A rubber

will cause the surge control valve

flap is attached to the lid to re-

to open on serial numbers 1012,

duce exposure of the TRU to rain or

1032,

and 1036 through 1155. The

snow. The TRU out-put is connected

con- tinuous bleed of GTE compressor

to the DC contactor as shown on FO-

out- put through a 1/4 inch diameter

5D.

hole in the union at the input to

the su- rge control valve has also

(4) The exhaust ejector assembly

been eli-

minated on these same

on the 83-360D has also been modi-

serial num-

bered AGPUs.

fied to reduce the back-pressure.

This improves the GTE efficiency,

b. Part Number 83-360D. This new

thereby increasing shaft horsepower,

part number has been assigned to

increaseing the pneumatic output and

selected AGPUs used to support the

reducing fuel consumption.

AH-64D, Longbow Apache helicopter

that have been modified by MWO 1-

(5) The continuous bleed of GTE

1730-229-50-2 to upgrade the 400

compressor output on all P/N 83-

Hertz, AC, output and the gas tur-

360D, is plugged and the jumper in-

bine engine performance. The up gra-

stalled on the current limit switch

ded AGPU has a new AC generator, a

for serial numbers 1012, 1032, and

modified

generator

control

Unit

1036 through 1155 is removed. The

(GCU), a transformer rectifier Unit

surge control valve opens only when

(TRU), a modified exhaust ejector,

the CURRENT LIMIT switch is set at

and associated wiring changes. Se-

the AH-64D/90KVA setting. The set-

rial numbers are not changed when

ting of the pneumatic system switch

MWO 1-1730-229-50-2 is applied.

no longer controls the function of

the surge control valve. A muffler

(1) The primary hardware change

has been added to the outlet of the

in corporated by MWO 55-1730-229-50-

surge control valve.

2 is replacement of the generator,

which has a combined 37.5 KVA AC and

(6) The marking on the current

700 amp DC output, with 48 KVA AC

limit selector on the control panel

generator. The 83-360D generator has

have been changed to identify

the

no DC output. The AC generator is

higher AC limits and to indicate

also a self-cooled, continuous duty,

that the DC current limiting and DC

self-excited, brushless unit, but

VOLTAGE FAULT indicator has been

doesn't have the two windings used

disabled. The TRU has only limited

to provide 28 VDC output. The rec-

output. A "MAX. CONT. 350 AMP" la-

tangular box on the top of the gen-

bels has been applied to the con-

nerator is eliminated. It contained

trol panel to indicate the reduced

the DC output terminals and the gen-

DC output. A "MAX. CONT. 130%" label

nerator control unit (GCU) con-

has been applied to indicate the in-

nector, which is located onto the

creased AC rating.

primary housing of the AC generator.

The connections to the output ter-

minals are changed to maintain the

NOTE

proper direction of rotation. (See

Figure 4-39a.)

There are only minor changes with

(2) The GCU has been modified to

the exterior of the AGPU. The 83-

control the larger capacity AC gen-

360D can be identified by ammo

erator. While the current limits may

identification plate located just

change, this modified GCU may be

below the nameplate and revised

used still be used with the com-

labeling the control panel. The

bined AC/DC generator on the P/N 83-

TRU can be seen on the upper left

360A. Since AC power is still need-

of the DC cableway, just under a

ed, even when only DC is being sup-

6-inch flexible flap marked "83-

plied by the TRU, the CURRENT LIMIT

-360D".

SELECTOR switch is rewired so that

the GCU is always monitoring the AC

output.

1-14 Change 8