FIELD OF THE INVENTION
Auto Stabliser Test Set is complete test facility for Testing of Auto Stabilizer Unit.
This unit provides automatic stabilization to Aircraft during Manuveres/Firing/ Flying etc
especially at Low altitude.
BACKGROUND OF THE INVENTION
The Auto Stabliser system is generally installed on various platforms. This unit
provides automatic stabilization to Aircraft during Manuveres/Firing/ Flying etc especially
at Low altitude. This Unit itself is a very complex system. Complete Autostab system is
required to be tested before any mission. A small, rugged, field level tester are required
to be designed which is able to test all the parameters of the Autostab unit. The present
invention is able for testing and measurement of all parameters of Autostab system.
The Autostab Test set contains facilities for the generation of test signals required
to excite the system under test and the measurement of signals as generated. Visual
display of test results is by means of pass and fail lamps. All signal sources and
measuring circuits are contained within the measuring module whilst the switch modules
contain the routing and selection facilities.
SUMMARY OF PRESENT INVENTION
In accordance with one aspect of present invention, it is capable of generating
various DC signals such as
• A DC constant current source suitable for driving self test coils.
• A DC constant current source for resistance measurements.
• A stabilized DC voltage injector set at 3.08V for earth fault measurements,
Accuracy ±3 per cent.
• A regulated -30V DC supply for driving relays.
• A regulated + 5V DC supply for the logic circuits.
In accordance with second aspect of present invention is capable of generating
various AC signal levels, derived from a precision 10V low impedance source in all
permutations of phase accuracy ± 6 %. All AC injections are mains proportional.
In accordance with yet another aspect of present invention is capable of providing
measurement in the steady state only. Accuracy over the range 100mV to 500V is ±3 per
cent and over the range 10mV to 100mV is ± 4 per cent. The measuring section is fully
floating and has a common mode rejection ratio of better than 100dB. Apart from this it is
able to provide fallowing measurement
• AC reference phase signal measurement.
• DC signal measurement.
• Resistance measurement, in conjunction with internal current source.
• A self- test facility where by correct functioning of the measuring circuits
can be checked.
• Earth fault detection, in conjunction with internal voltage source.
• Gyro wheel running check.
BRIEF DESCRIPTION OF THE DRAWINGS
The features and advantages of the present invention will become more apparent
and descriptive in the description when considered together with figures presented:
Fig. 1 is a General view of Auto stab test set
Fig. 2 is a Front Panel view of Auto stab test set
Fig. 3 is a Tree diagram of Auto stab test set
Fig. 4 is a Schematic diagram of Auto stab test set
DETAILED DESCRIPTION
The Autostab Test set contains facilities for the generation of test signals required
to excite the system under test and the measurement of signals as generated. Visual
display of test results is by means of pass and fail lamps. All signal sources and
measuring circuits are contained within the measuring module whilst the switch modules
contain the routing and selection facilities.
Tests are selected by setting the switch module selectors to specific positions.
Measurement is then automatically carried out when the TEST switch is operated and
indication of an acceptable or unacceptable result given by the green PASS or red FAIL
lamps.
The fig. 1 is the general view of the Auto Stab Test set; The Auto Stabilizer first
line test set is housed in a case size L=489.5,W=272, D=389. The lid of the case is
secured with four knurled bolts which can be opened by unscrewing the bolt to expose
the controls mounted on front panel (Fig.-2). The panel is secured to the case by 8
screws located around the both side of the panel.
The front panel titles are marked in English alphabet finished in black. The panel
is finished anodized aluminum color and case and lid in orange.
All connections between the aircraft system under test and the test set are made
via two 9-metre cables which connect to plugs PITCH/YAW and ROLL on the front panel.
The 115V, 400Hz power supply to the test set is provided by the system under test.
All tolerances quoted will be held over the temperature range –10°C to + 35°C but
may be doubled over the range -30° to +55°C.
No derangement will occur with power off over the range -65°C to +71°C.
Measurement accuracy
On 500V to 100mV ± 3%
100mV to 10mV ± 4%
AC injection accuracy ± 3%
DC injection ± 3%
The indicators and controls, comprising the PASS, FAIL and ! (Inhibit) lamps, the
BALANCE and PASS LEVEL potentiometers and the TEST, WASHOUT, MANO
NORMAL-SIM, NORMAL-REVERSE and FUNCTION-SELF TEST switches are all
secured to the front panel. (See fig-2)
Printed circuit boards PCB1, PCB2 and PCB3 are connected into the module via
three connectors. This renders them easily replaceable during repair.
A.C and D.C measurements
The measuring circuit (fig-4) basically comprises an amplifier/demodulator
comparator and logic circuits controlling display lamps. The mode of operation of the
measuring circuits selected by a number of relays are being in turn selected by the rotary
selectors in the switching module such that a direct input level of 100mV or 10mV (AC,
DC, normal, reverse) results in an amplifier output of +5Vfor normal signal
measurements.
Self Test Facility
This facility is utilized by setting the SELF TEST/FUNCTION switch to SELF TEST
and adjusting the PASS LEVEL potentiometer (see fig.2). The correct functioning of the
measuring circuits is then checked by applying a varying AC signal level from the PASS
LEVEL potentiometer to the measuring circuit input. The potentiometer is adjusted and
the operation of the green PASS lamp and red FAIL lamp checked with respect to the
setting of the potentiometer.
Earth fault detector
This facility checks whether the insulation resistance between the line and earth is
below or above 150K ohms. This is achieved by connecting the measuring circuit to
measure the voltage developed across the test circuit forming part of a potentiometer
circuit, fed from the 3.08V DC source. This is then displayed as a PASS or FAIL.

WE CLAIMS:-
Accordingly, the description of the present invention is to be considered as illustrative only and is for the purpose of teaching those skilled in the art of the best mode of carrying out the invention. The details may be varied substantially without departing from the spirit of the invention, and exclusive use of all modifications which are within the scope of the appended claims is reserved. We Claim

1. The auto stabilizer test set is designed to test auto-stabilizer unit, consisting of
- Switch module-Assy. (Pitch/Yaw)
- Switch module-Assy. (Roll)
- Transformer Assy.
- Customized PCB Assy.
- Pitch/Yaw Cable
- Roll cable
- Measuring module

2. The Autostab Test set of claim 1 wherein, said equipment is capable of generating various DC signals such as
• A DC constant current source suitable for driving self test coils.

• A DC constant current source for resistance measurements.

• A stabilized DC voltage injector set at 3.08V for earth fault measurements, Accuracy ±3 per cent.

• A regulated -30V DC supply for driving relays.

• A regulated + 5V DC supply for the logic circuits.

3. The Autostab Test set of claim 1 wherein, said equipment is capable of generating various AC signal levels, derived from a precision 10V low impedance source in all permutations of phase accuracy ± 6 %. All AC injections are mains proportional.

4. The Autostab Test set of claim 1 wherein, said equipment is capable of providing measurement in the steady state only. Accuracy over the range 100mV to 500V is ±3 per cent and over the range 10mV to 100mV is ± 4 per cent. The measuring section is fully floating and has a common mode rejection ratio of better than 100dB. Apart from this it is able to provide fallowing measurement

• AC reference phase signal measurement.

• DC signal measurement.

• Resistance measurement, in conjunction with internal current source.

• A self- test facility where by correct functioning of the measuring circuits can be checked.

• Earth fault detection, in conjunction with internal voltage source.

• Gyro wheel running check.

5. The Autostab Test set of claim 1 wherein, the Autostab Test set is housed in a compact box carrying handle. ,TagSPECI:As per Annexure-II