TI47UH1 MPU-24
20
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 unit 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 the
aircraft voltmeter should indicate 28.5 Vdc. If aircraft power demand is less then 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 more than 10 amps. DC bus power should come on and
aircraft’s voltmeter should indicate between 24 Vdc minimum and 27.6 Vdc maximum. If current demand is
above 10 amps, converter output voltage will drop below 27.6 Vdc and two or more LED status indicator bars
will illuminate. At approximately 10 amps of current demand, converter output voltage will be regulated at
24 Vdc output and the last (red) LED status indicator bar will illuminate.
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.