L1011 - CPT - DC Power Planning

L-1011 DC Power for the Simulator

I am planning on using two types of 24VDC power supplies to simulate the Transformer Rectifier units on the L-1011. A Transformer/Rectifier (TR) takes a high voltage AC power source and first transforms it to a lower voltage and the uses a rectifier to convert it to a DC power source. The units are made by Phoenix Contact and will be mounted on DIN Rails as part of the electrical outfit of the L-1011 Procedure Trainer:

1. Phoenix Contact Trio PS 1AC/24DC/10A
2. Phoenix Contact Quint PS 1AC/24DC/20A

There are a total of four transformer rectifier (TR) units on the L-1011. On the actual aircraft the TR units powered by individual 115V 400Hz power from engine driven generators, inverters or a ground power supply. However, for the simulator we will keep the need for 400Hz power to a minimum, therefore, as you can see int he diagram above we will drive the simulated TR units from regular 120V 60Hz commercial power. 

Both the AC as well as the DC power distribution systems on the L-1011 are designed for maximum availability. Lets take a look at the actual L-1011 DC power schematics.

L-1011 DC Power Schematics

The schematic above shows the TR units on the left hand side and the individual DC buses going left to right with the DC Tie Bus on the right hand side. A single TR can drive all oft the DC buses via the DC Tie bus. All DC buses can be isolated with the DC Tie Breakers. Again, the system is build for maximum availability and the ability to provide a high degree of fault isolation while in flight.

While many of the general DC bus systems are interesting to implement, the simulator uses a great amount of DC power for driving instrumentation. The diagram below shows the DC and AC power distribution buses for the Radios on the L-1011.

L-1011 Radio DC Power Distribution

All in all the SIM will require four 10A units and two 20A units. Next we will look at the AC power distribution needs for the simulator.