XHHG521based on MURRAY Bridge to be designed which can be used to locate the breakdown point of all kinds of underground cable and
the defect point of low insulation resistance without breakdown. Also can be used to locate the defect point of cable for cable
manufacturer. XHHG521 adopts switching power to make up high voltage constant current source.7.5kv no load voltage, 40mA short
circuit current. It uses high sensitive amplifier galvanometer and potentiometer to be balance bridge; Under High potential to
test special high voltage double core rubber cables.Four-terminal resistance measurement avoid error by lead resistor. The cable
is reliably grounded through the braided shield. Operation buttons under low potential, we can operated bridge by insulating rod.
High voltage constant current and bridge are in one portable aluminium alloy case. High voltage light weight easy operate and
safety. Compared with ARC, balance bridge is no dead zone. It is especially suitable for judging breakdown point of short circuit
cable.

XHDD503A Digital Power Cable Fault Pin-pointer is an easy operation device used to pinpoint the fault point. It integrated the function of acoustic magnetic synchronization method, the step voltage method, the magnetic field strength method to make the pinpointing accuracy

Testing step:

1. Check the breakdown status of the cable with a multimeter, a rocking watch or other pressure resistant equipment, and record the value of each core's insulation resistance against the ground or residual voltage breakdown.

 

2. Record the length, model, cross section and other parameters of the cable to be tested, and inspect the route along the cable laying path. In the remote short-circuit fault cable and the auxiliary cable outlet terminal, leave one person at the remote monitoring to avoid high-pressure injury.

 

3. wiring. The ground of the instrument is reliably connected to the grounding body of the positioning site.
Ground rods are connected to the instrument ground. The measuring head (black clip) is connected to the faulty cable core and the
measuring end (red clip) is connected to the auxiliary cable core.

 

4. bridge zero (high voltage knob is not zero). Turn on the
power and rotate the zero button to zero the galvanometer.

 

5. power supply connected to AC220V.

 

6. Boost pressure. Turn on the
power switch and the power indicator lights up. When the high pressure knob is turned counterclockwise, the zero position is
activated.

 

7. Turn the high pressure knob clockwise and watch the voltmeter and ammeter until the ammeter exceeds 5mA. If the current is not stable, the voltage may continue to rise for a period of time to form a stable arc or conductive area, stabilizing the current during the test.

 

8, balance adjustment. Rotate the zoom knob clockwise to increase the sensitivity step by step until
the galvanometer deflects significantly but does not overshoot. Rotate the dial to make the galvanometer zero. (If the pointer is
to the left, rotate clockwise, the pointer is to the right, and counterclockwise). Take note of the reading P1 of the cymbal dial
at this time.

 

9, drop voltage, discharge. The clamp exchange position will be measured and steps (4) to (10) will be repeated to
obtain another reading P2, which should have P1+P2=1000

 

10. Calculation. Location of fault point X=2×L ×P1‰ Pay more attention to
the "2" in the formula. The auxiliary cable will double the number of cables involved in the calculation.

Xi'an Xu&Hui Electromechanical Technology Co.,Ltd are one of famous brand of electrical equipment tester manufacturer in China, mainly produced underground cable fault locator, capacitors, insulation resistance tester, transformer oil tester, high voltage generator and earth resistance tester etc. We have several patents in this industry, and our products are export well in the global market, such as America, Brazil, Turkey, Russian,Israel, Thailand, India, etc.