FIELD OF THE INVENTION
The present invention relates to instrument for testing discrete capacitors
stack for leakage and functional deterioration.
BACKGROUND OF THE INVENTION
The capacitors stack are temperature sensitive and are prone to becomes
leaky during stacking process, which results in poor performance and eventually
short circuits.
Approximately 50% capacitor stacks get short circuited during the system
level testing which causes poor reliability.
Conventionally discrete Capacitor stacks are checked using LCR/DMM for
its capacitance value. However, DMM is not capable of detecting latent failures
attributed to leakage hence, latent failure components can not be segregated
before assembly in PWA.
The present invention is capable of testing capacitor stack wherein it is
subjected to same electrical stress. Latent failures are detected and suspected
components / stacks are segregated before its assembly on board.
SUMMARY OF PRESENT INVENTION
In accordance with one aspect of present invention is to simulate the same
electrical conditions through which capacitor stack undergoes during its functional
operation.
In accordance with second aspect of present invention is to detect the latent
failure components as well as faulty and healthy components for segregation.
In accordance with yet another aspect of present invention it is capable of
identifying the component failure with indicator lamps.
In accordance with yet another aspect of present invention is portable
equipment with appropriate dimensions enclosing requisite circuit and its
ancillaries.
Annexure-II
BRIFE DISCREPTION OF DRAWING:
The features and advantages of the present invention will become more
apparent and description in the description together with figures presented:
Figure 1: Block diagram of said instrument.
Figure 2: Front view of said instrument.
Figure 3: Top view of said instrument.
Figure 4: Side view of said instrument.
DETAIL DESCRIPTION
Fig. 1 shows the block diagram of capacitor leakage tester with a power supply
block along with an indicator and protection fuse.
A step down transformer along with rectifier provides requisite dc voltages for
powering up the circuit.
Two numbers of potentiometer pairs are mounted on PCB which form reference
voltage block. (Refer Fig. 1)
Two LED display indicate test conditions during testing of capacitor stack. (Refer
Figure 1 and 2)
Two numbers of precision comparators are used for comparing the leakage current
sample with two reference voltages. (Refer figure 1)
Capacitor charging block in figure 1, charges the capacitor stack with constant DC
bias voltage source.
Leakage current sampling block in figure 1, converts the leakage current sample in
proportional DC voltage.
Figure 2, 3 and 4 shows visual appearance of capacitor leakage tester from front,
top and side of view.
The front panel consists of
1) ON/OFF toggle switch
2) LED indicators
3) Capacitor mounting clamps

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 said instrument, a testing tool for detecting leakage current flowing through capacitor stack, comprising:
- LED indicator for illumination
- ON/OFF toggle switch
- Protection Fuse
- Internal Looms
- Capacitor Stack Mounting Clamps &
- Internal circuit PCB

2. The Capacitor stack leakage tester of claim 1 detects faulty capacitor stack by atleast three states indicating with combination of LED1 and LED 2.

3. The Capacitor stack leakage tester of claim 1 is portable equipment with appropriate dimensions enclosing required circuit and its ancillaries.

4. The Capacitor stack leakage tester of claim 1 is capable of identifying latent failures of components which subsequently improves the reliability of assembly.

5. The Capacitor stack leakage tester of claim 1 detects leaky components with the help of two precision comparators.

6. The Capacitor stack leakage tester of claim 1 wherein, the leakage voltage developed by capacitor Stack is compared with two precision comparators adjusted at two different reference levels.

7. The Capacitor stack leakage tester of claim 1 wherein, capacitor stacks are segregated in three different categories indicated with a combination of ON / OFF states of two LED indicators. ,TagSPECI:As per Annexure-II