Pratt & Whitney Rzeszów S.A.
MAINTENANCE MANUAL
PZL-10W ENGINE
1992.08.28
73-22-03
Page 3
Export Control Classification: PL/UE 9E999
The signal of the power turbine rotational speed delivered from the pick-up and converted on
rectangular signal is fed through the transformer coupling to the pull-push transistor impulse
formation. These impulses are to be averaged with the help of the filters, giving the proportional
voltage to the power turbine rotational speed. This voltage is compared to the basic voltage and in
the case when the signal voltage value is higher than the basic voltage value corresponding to the
unsafe level of the power turbine rotational speed, the relays are actuated, which actuation feeds
the voltage to the electromagnet of the shut-off valve in the fuel metering pump, causing the fuel
delivery shut-off to the engine. Simultaneously the voltage is fed to the actuation signaling of the
electromagnetic shut-off valve.
The voltage disconnecting from the electromagnet coil requires the switch push canceling the
emergency valve actuation. Repeated engine starting would be impossible without making this
operation.
(2)
Measurement of the compressor turbine rotational speed - is made on the base of the signal
delivered to the electronic limiter unit from the pick-up positioned on the fuel metering pump.
The frequency of this signal is proportional to the rotational speed of the toothed wheel driven by
the engine compressor turbine. This signal is next converted for the rectangular signal of the high
amplitudę, and with the help of the frequency-voltage converter is changed for the signal
proportional to the compressor turbine rotational speed. This signal is fed to the circuit of the
corrected compressor turbine rotational speed, to the circuit of the compressor turbine rotational
speed limiter, to the circuit preparing the signals for the starting system, to the OEI power system,
to the engine operation time counters as well as to the circuit comparing the signal from the
integrator tracing the lowest signal gate with the voltage signal proportional to the compressor
turbine rotational speed, to create the error signal for the electrohydraulic amplifier control.
(3)
Measurement of the power turbine rotational speed - is made on the base of the signal fed to the
electronic limiter unit from the pick-up positioned on the drive gearbox of the power turbine
rotational speed limiter.
The frequency of this signal is proportional to the rotational speed of the toothed wheel driven from
the power turbine.
This signal is next converted for the rectangular signal of high amplitude and with the help of the
frequency-voltage converter is changed for the voltage signal proportional to the power turbine
rotational speed. This signal is fed to the electronic controller of the power turbine rotational speed.
(4)
Circuit preparing the signals to the starting system and to the OEI power system - consists of two
comparator units that change the state after exceeding the two levels of the compressor turbine
rotational speed. Two bistable elements control the voltage signal proportional to the compressor
turbine rotational speed and change the state at achieving the set levels ( first at N1 = 45% and
second at N1 = 58%),