| 摘要 |
A signal processor (30) compares the speed of rotation of an aircraft propeller (5) with a reference signal to effect disconnection of propeller heaters (40, 50, 55 and 65) from a power supply (10) when the propeller speed falls below a minimum value at which heater burnout is prevented by airflow over the propeller surface. As described the processor (30) controls a heater circuit protection switch (215) between a power supply 210 and a timer and sequencer control unit 205 for the heaters which operates solenoid switches (160, 165, 170) in the power supply circuit for the heaters. This circuit also includes manual switches (150, 155, 160). The control unit (205) allows for continuous energisation of some of the heaters and cyclical energisation of others, as is known in the art. <IMAGE> |
