POWER INDICATING - DESCRIPTION AND OPERATION
____________________________________________
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.
2.
Component Location
__________________
(Ref. Fig. 001)
-------------------------------------------------------------------------------FIN | FUNCTIONAL DESIGNATION | PANEL|ZONE|ACCESS | ATA
| | | | DOOR | REF. -------------------------------------------------------------------------------113KD SPEED SENSOR 1 315 315AL 49-71-13
3.
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.
4.
Interface
_________ The power indicating system has interface with the Control and Monitoring System (Ref. 49-61-00).
5.
Component Description
_____________________
A. Speed Sensor
The speed sensor consists of:
-
a magnetically soft-pole piece,
-
a permanent magnet,
-two coils,
located in a hermetically sealed housing.
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.
R EFF : 001-049, 101-105, 107-107, 151-199, 49-71-00Page 1 201-210, Config-2 Aug 01/05
CES
APU Power Indicating - Speed Sensor
Figure 001 (SHEET 1)
CES
APU Power Indicating - Speed Sensor
Figure 001 (SHEET 2)
CES 6. Operation/Control and Indication
________________________________ (Ref. Fig. 002) 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.
R EFF : 001-049, 101-105, 107-107, 151-199, 49-71-00Page 4 201-210, Config-2 Aug 01/05
CES
APU Power Indicating - Block Diagram
Figure 002
CES
POWER INDICATING - DESCRIPTION AND OPERATION
____________________________________________
1.
General
_______ The power indicating system monitors the APU speed in revolutions per minute (rpm). Two speed sensors transmit a signal to the ECB 59KD. The ECB 59KD gives a speed signal to the Electronic Instrument System (EIS). The EIS shows the APU speed in percent on the APU system page at the lower ECAM display unit.
2.
Component Location
__________________
(Ref. Fig. 001)
-------------------------------------------------------------------------------FIN | FUNCTIONAL DESIGNATION | PANEL|ZONE|ACCESS | ATA | | | | DOOR | REF.
-------------------------------------------------------------------------------SPEED SENSOR 1 315 315AL 49-71-13 SPEED SENSOR 2 316 316AR 49-71-13
3. System Description
__________________ (Ref. Fig. 001, 002) The power indicating system shows the APU speed on the EIS. Two speed sensors are installed in the gearbox casing. Each of the speed sensors is connected to the ECB 59KD. The ECB 59KD receives the speed signals from the speed sensors and transmits the speed signal to the EIS. The EIS shows the APU speed in percent on the lower ECAM display unit.
A Permanent Magnet Generator (PMG) is connected to the ECB. The PMG is installed in the cooling fan of the accessory cooling system (Ref. 49-52-00). The ECB receives the PMG speed signal and uses it for the back-up overspeed protection.
4.
Interface
_________ The power indicating system has interface with the Control and Monitoring System (Ref. 49-61-00).
5.
Component Description
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