Ver

A-phase output

B-phase output

Ophase output

15 V dc

Fuse

Figure 92.- Block diagram of 400-Hz three-phase inverter.

off by an ACS signal to the power subsystem that actuated a magnetic latching relay. Each inverter output was connected to a given inertial reference unit, the only users of 400-Hz power on the VO. Figure 93 shows typical efficiency-load characteristics of the 400-Hz three-phase inverter.

The 30 V dc converter subassembly contained two identical converters that operated in a parallel redundant configuration. (See block diagram in fig. 94.) Both converters were simultaneously switched on or off as needed during the mission via signals from the CCS, and either converter was capable of handling the entire expected load should the other fail. Both the input and output power of the converters were switched by redundant relays that were controlled by the CCS commands. The unit converted to 30 V dc the regulated 55.2 V dc output from the B/R at its redundant bus. The 55.2 V dc was filtered to reduce the introduction of ripple current to the converters. Each converter consisted of a driver and a full-wave switching inverter followed by a transformer-rectifier-filter unit. The inverters were driven by a square-wave signal from the 2.4-kHz power line. In each converter, a balanced output from the input transformer fed the bases of a pair of switching transistors that drove a power transformer.

Red mid an t 56 V dc f rotr pwr control

Fuse dc input f 1

2.4 kHz f rom pwr con t ro1

Red mid an t 56 V dc f rotr pwr control

Fuse

15 V dc

0 0

Post a comment