DOC AIRBUS | AMM A320FPOWER INDICATING - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The power indicating system monitors the APU speed. The Electronic Instrument System (EIS) shows the APU speed in percent on the APU SYSTEM page at the lower ECAM display unit.
** ON A/C NOT FOR ALL The power indicating system monitors the APU speed. The Electronic Instrument System (EIS) shows the APU speed in percent on the APU SYSTEM page at the lower ECAM display unit.
** ON A/C NOT FOR ALL
APU Power Indicating - Speed Sensor3. System Description
One speed sensor is installed at the bottom-right side of the gearbox. The speed sensor converts the rotation of the APU compressor-turbine shaft into electrical energy (sinusoidal frequency). This frequency is proportional to the rotating speed of the compressor-turbine shaft.
Due to the dual-coil design of the speed sensor, the ECB receives two independent speed signals. The ECB compares the two signals and evaluates the highest signal for further processing and indication.
** ON A/C NOT FOR ALL One speed sensor is installed at the bottom-right side of the gearbox. The speed sensor converts the rotation of the APU compressor-turbine shaft into electrical energy (sinusoidal frequency). This frequency is proportional to the rotating speed of the compressor-turbine shaft.
Due to the dual-coil design of the speed sensor, the ECB receives two independent speed signals. The ECB compares the two signals and evaluates the highest signal for further processing and indication.
4. Interface
The power indicating system has interface with the Control and Monitoring System (Ref. AMM D/O 49-61-00-00).
** ON A/C NOT FOR ALL The power indicating system has interface with the Control and Monitoring System (Ref. AMM D/O 49-61-00-00).
5. Component Description
A. Speed Sensor
The speed sensor consists of:
The displacement of gear-like teeth on the compressor-turbine shaft induces an AC current in the two coils of the speed sensor. The frequency of this current is proportional to the rotating speed of the APU.
The speed sensor consists of:
- a magnetically soft-pole piece,
- a permanent magnet,
- two coils,
The displacement of gear-like teeth on the compressor-turbine shaft induces an AC current in the two coils of the speed sensor. The frequency of this current is proportional to the rotating speed of the APU.
6. Operation/Control and Indicating
The two frequency signals, corresponding to the APU rotation speed, are transmitted to the ECB. By comparison the ECB evaluates the highest speed signal. This signal is used by the ECB for control and monitoring the APU speed during all APU operating conditions.
Additionally the signal is transmitted via an ARINC 429 bus to the EIS.
The APU SYSTEM page on the lower ECAM display unit shows the APU speed in percent in an analog and a digital display.
The two frequency signals, corresponding to the APU rotation speed, are transmitted to the ECB. By comparison the ECB evaluates the highest speed signal. This signal is used by the ECB for control and monitoring the APU speed during all APU operating conditions.
Additionally the signal is transmitted via an ARINC 429 bus to the EIS.
The APU SYSTEM page on the lower ECAM display unit shows the APU speed in percent in an analog and a digital display.