TB 1-1730-229-20-2
(2) Add: On the 83-360D, all the AGPU's DC output power is supplied by the TRU,
which is powered from the AC output of the generator. The GCU on the 83-360D must remain
in the AC mode to regulate this AC output. The GCU has been disconnected from the DC
contactor K2 and a jumper has been installed to allow the contactor to close whenever the DC
POWER switch is set to ON.
(3) Add: On the 83-360D, the GCU can only operate in the AC mode. DC current
limiting and DC voltage fault monitoring are not provided.
(4) Add: The TRU used on the 83-360D, is a rugged solid-state power converter
currently used on the AH-64A helicopter to provide essential DC power. It has a minimum
continuous output voltage of 26 VDC at a 250 amp and 25 VDC at a 350-amp output. Ripple is
1.5 volt maximum. Maximum output is 500 amps for 1 minute, 1000 amps for 6 seconds.
(5) Add: The TRU on the 83-360D is protected by an overheat indicator. Activation of
this switch will illuminate the DC OVER CURRENT light (DS19) on the control panel. Neither
the TRU nor the GCU can open the DC contactor to prevent continued overheating of the TRU.
Activation of the overheat indicator is most often caused by a failure of the TRU cooling fan.
Table 4-12 is not applicable to the 83-360D.
Figure 4-37. Output Power Cables, 400 Hz AC-to-DC TRU, and DC-to -60 Hz Inverter
The TRU will be added to this figure as item 4, located in the upper right side wall of the
DC cable compartment.
Table 4-12. Generator DC Faults (Page 4-210)
Change title to "Generator DC Faults, 83-360A Only"
b. AC Power Generation and Control. (Page 4-211)
(5) Add at line 6: "On the 83-360D the current limit setting are: 17 KVA, 38 KVA,
59 KVA (AH-64A/H-60), and 90 KVA(AH-64D)".
Change title to "Generator AC Faults, 83-360A Only"
11
