CHAPTER 2
UNIT DESCRIPTION AND OPERATION
SECTION I. UNIT
2-1. GENERAL
The TI4676 (Figure 2-1) is a compact, portable and highly versatile 24/
28.5 VDC electrical MPU. The unit incorporates a 120-240 50/60 Hz to
28.5 VDC converter, a 24 volt unique (dry) power cell and an internal
intelligent 120-240 50/60 Hz VAC charger to recharge the power cells.
In addition the MPU incorporates a push to test button which gives the
user the ability to test the capacity of the power cells These built-
in features give the TI4676 self-sufficiency in an aircraft battery,
and long term ground operations with AC electrical power. Aircraft bat-
tery operations rely on the unique dry-cell batteries that can be rap-
idly recharged from the aircraft generator or any common 120-240 50/60
Hz VAC source. Ground operations incorporate the continuous 12 Amp
output of the 120-240 50/60 Hz VAC to 28.5 VDC converter, or a combi-
nation of converter and power cell output to provide 24 VDC output.
The following are the unit’s five (5) main operational support capa-
bilities:
a. 24 VDC 1500 amp peak power output for engine starting or constant
(one hour) rated power output (without a 120-240 50/60 Hz VAC power
source) for short-term trouble shooting.
b. 24 VDC constant (one hour) rated power output or variable high
load demand output (less than one hour) with a 120-240 50/60 Hz VAC
power source for extended maintenance (hangar) and routine flight
line maintenance, ground support power.
c. 28.5 VDC continuous rated (AC to DC converter) power output with
a 120-240 50/60 Hz VAC power source for hangar and routine flight
line maintenance support.
d. Rapid recharge of the unit’s power cells from aircraft generator
or any 120-240 50/60 Hz VAC common power source. This feature elimi-
nates the need for special recharge equipment and dedicated mainte-
nance support man-hours.
e. Built in Capacity tester and state of recharge indicator.
2-1