Woodward 8923-2690 Turbine Shutdown Trip Block Assemblies

The MicroNet Plus Expansion Chassis may use either single or redundant power supplies.

Each power supply module produces three regulated outputs: 

24 V @ 12 A (max), 5 V @ 32 A (max, derated above

55 degree C external ambient temperature), and 5 V Precharge @ 3 A (max).

A motherboard located on the back of the chassis provides the 

interconnection of the three outputs from each power supply module

into three corresponding power busses: 24 V bus, 5 V bus, and 5 V precharge bus.

The 24 V and 5 V busses are load shared between the two power supply modules.

The 5 V precharge bus is not load shared.

Each of the three ProTech units must be reset before the turbine is started. A unit

is reset by pressing the front panel RESET button or by momentarily closing the

remote reset contact (TB5-4 to TB5-5). After the power-up self-tests, each

ProTech unit begins executing its speed-sensing algorithm. If the speed does not

exceed the MPU FAIL SETPOINT speed within the MPU FAIL TIMEOUT value,

the unit trips. At this time the MPU FAIL LED turns on and remains on until the

next reset. This trip is not affected by the TRIP ON MPU FAILURE option. The

ProTech overspeed protection system will trip on an overspeed condition during

start-up.