.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
(5) Engine Starter-The pneumatic starter is powered by bleed air, typically from APU, it motors the Ng section via the AGB and PTO. It decouples (via internal clutch) from the AGB when the engine is running. Starter limitations exist because the bleed air powering it is hot (400oF) and can damage the starter if exposure time is excessive.
The engine starter is an air powered starter that motors the engine for starting. Compressed air acts upon the starter turbine wheel, which motors the Ng section via the AGB/PTO link. When engine RPM is greater than the starter (engine running), the starter disengages from the AGB via a one-way clutch within the starter. A magnetic pickup on the starter feeds an Ng speed signal to the speed switch (auto-start circuit) to effect starter dropout between 52 to 65% Ng. Extended starter operations can cause damage due to the high temperature of the bleed air driving the starter (about 400o F). Refer to TM 1-1520-237-10 for starter limitations.
UH-60 START SYSTEM
(electrical/mechanical/pneumatic) PCL electrical functions:ver 1.0
d. Power Control Lever four Mechanical Functions; OFF, IDLE, FLY, and LOCKOUT.
(1)
When the PCLs are in the OFF position, the fuel flow to the engine is stopped. In the OFF position, the fuel shut-off valve inside the HMU is mechanically closed through the linkage to the Power Available Spindle (PAS).
(2)
With the PCLs in the IDLE position, the fuel flow begins, the HMU meters the idle fuel flow, and the engine is set at idle speed (63% Ng).
(3)
In the FLY position, fuel flow is set to maximum, and the ECU trims the fuel flow in order to maintain 100% Np and Nr.
(4)
Placing the engine power control lever in lockout allows the pilot to manually control the fuel flow while bypassing ECU to HMU functions. When the PCL is in LOCKOUT, care must be taken to keep the engine TGT within the operational range.
CAUTION: When engine is controlled with the ENG POWER CONT lever in LOCKOUT, engine response is much faster and TGT limiting system is inoperative. Care must be taken not to exceed TGT limits and keeping %RPM R and %RPM 1 and 2 in operating range.
e. Power Control Lever Electrical Functions; START SWITCH, OVERRIDE SWITCH, and the ABORT SWITCH.
CAUTION: To avoid damage to the engine start switch actuators, do not move the ENG POWER CONT lever from IDLE to OFF while pressing the starter button.
(1)
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：UH-60A STUDENT HANDOUT UH-60A T700 ENGINE(18)
