TI47UH1-46AH MPU-24
19
4
Operating Procedures
4.10 – Regulated 28.5 Vdc Output Ground Power
Connecting DC Power Cable To Unit
Attaching a dc plug is quick and easy. Line up the plug with the receptacle. Push forward while rotating
the T-handle one full turn clockwise. Ensure dc power cable plug is fully seated into the MPU’s dc battery
receptacle. The unit is now ready to safely transfer power.
4.11 – Regulated AC Power
Plugging in with AC Power
When the TI47UH1-46AH MPU-24 is plugged into ac power, the output is 28.5 volts. This voltage allows
the system to recondition and recharge the aircraft’s battery(ies). It is also an optimum voltage for
powering avionics and lighting on most aircraft. The MPU’s ac to dc converter produces continuous amps
of dc power depending on the size of the system.
Ensure 120 or 240 Vac power cord is properly connected to an approved ac power supply. After
approximately 5-8 seconds, unit’s LED status indicator will illuminate indicating power cell state of charge.
Cooling fan will operate. Ensure LED status indicator and cooling fan is operational prior to continuing.
4.12 – Power to Aircraft
Low Power Demand
Low power demand is defined by a requirement of 10 amps or less. DC bus power should come on and
aircraft voltmeter should indicate 28.5 Vdc to 27 Vdc (26.5 Vdc minimum). If aircraft power demand is
less than 10 amps converter output will remain at 28.5 Vdc (only one GREEN LED status indicator bar will
illuminate). If aircraft power demand exceeds 10 amps, converter voltage output will decrease and two or
more LED status indicator bars will illuminate.
High Power Demand
High power demand is defined by a requirement of greater than 10 amps. DC bus power should come
on and aircraft voltmeter should indicate 28.5 Vdc to 23.5 Vdc (23 VCD minimum). If current demand is
greater than 10 amps, converter output voltage will drop below 28.0 Vdc and LED status indicator lights
will illuminate indicating current is being drawn from the power cells. The greater the current draw, the
quicker the LED status indicator will approach red. Note the LED status indicator shows the status of the
power cells.
NOTE
!
When all LED status indicator bars illuminate, both the converter and power
cells are supplying 24 Vdc power output for current demands above 10 amps.
Engine Starting
Check dc power cable for secure and correct installation prior to engine starting. Follow ground power
engine starting procedure as specified in vehicle operator’s manual.