TM 55-1520-240-23-7
8-1
ENGINE INSTRUMENTS
(Continued)
8-1
TORQUE INDICATING SYSTEM WITH 74
Description
The torque indicating system, which monitors the engine
power output, is a ratio detector system. It measures
and indicates the amount of engine torque. The system
consists of two dual torque indicators on each pilot’s
instrument panel, an engine driven power shaft, a head
assembly and a junction box on each engine, and two
separate torque signal processor/power supply units.
The torque signal processor/power supply units are
mounted in the aft cabin ceiling at left hand sta. 465 and
right hand sta. 474.
NO BREAK - WORK HARDER
The torquemeter head provides an electric torque signal
that is proportional to the twisting motion of the power
shaft. That signal is transmitted through a cable to
the junction box. The junction box is mounted on the
engine inlet housing. It provides operating power for the
torquemeter head and receives signals from the head
and sends them to the torque signal processor/power
supply. The engine driven power shaft, head assembly
and junction box make up a matched assembly. If one
component is bad, all three must be replaced with a
matched set.
NO BREAK - WORK HARDER
The torque signal processor/power supply provides a 6
kHz constant current signal to the torquemeter head. It
processes the signal coming from the junction box and
sends this signal to cockpit torque indicator and engine
digital electronic control unit (DECU).
NO BREAK - WORK HARDER
The torque indicator is calibrated 0 to 150 percent. It
has two pointers each marked with the number of its
respective engine. Electrical connections are provided
through connectors at the rear of each indicator. The
indicator is hermetically sealed.
8-11
