Insulation Resistance Tester

ZC-7 Insulation Resistance TesterZC-7 Insulation Resistance Tester
Applications
The ZC-7 tests the insulation resistance of: transformer and distribution stations, motors, power cables, transformers, telecommunication components, computer labs, household appliances and other apparatus.
Specifications and Features
Using condition: Temperature range -25ºC~+40ºC, Humidity ≤80%Rated crank speed:120r/min Calibrating arc length: about 68mm Dimensions:1xbxh.mm:(170x110x125) Weight: 2kg approximateEffect of incline: When the tester is inclined from its working position at an angle of 5 degrees, a change 50% of the grade index is allowed.Effect of outside magnetic field: When the outside magnetic field intensity is 0.4Ka/m, a change 100% of the grade index may take place.Specifications: measurement range, rated output voltage, accuracy and insulation resistance withstanding voltage are illustrated in the following table.
TypeSpecificationMeasurement Range M
Accuracy(grade)Insulation resistanceWithstanding VoltageVM
MKV
ZC-71001000~10010301.5ZC-71002000~20010301.5ZC-72502500~25010301.5ZC-72505000~50010301.5ZC-75005000~50010301.5ZC-750010000~100010301.5ZC-7100010000~100010302ZC-7100020000~200010302ZC-7250025000~250020503.5ZC-7250050000~500020503.5ZC-7500050000~500020505.4ZC-75000100000~1000020505.4Operating instructions
1. Place the tester in a horizontal position and make sure it is away from magnetic field when using.
2. Initial testing: Swing the crank at a speed of over 120r/min, if the coil side and the earth terminal are not connected to the measurement traverse line, the pointer should be at the position of∞, which is the indication of an open circuit. Then connect the measurement traverse line of the coil line and earth terminal short-circuit, swing the crank gradually up to a speed less than 120r/min, the pointer at the position of zero is the indication of short circuit. Tum to qualified personnel if necessary.
3. When testing insulation, connect the ends of the item under test to the "earth terminal" and "coil side" respectively. After that, swing the crank, the resistance value can be obtained.(see Figure 1)
4. When conducting the ground test, connect the "coil side" to the line under test and the "earth terminal" to ground wire.(see Figure 2)
5. When testing the insulation of cable core from its shell, besides the connecting of two terminals respectively, you should connect the inner layer insulator between the core and shell to the "shielding" in order to eliminate the surface leakage.(see Figure 3)6. Stranded wire cannot be used as the conductor between terminals and the item under test. The terminals should be connected separately to avoid the display failure resulting from the insulation defect.
7. The tester cannot be used when lightning strikes or when there is high voltage equipment nearby. only when the equipment is free from electric charges or impossible to be charged by other power induction can the measurement be conducted.
8. Fully discharge the item under test before or after measuring, so that the safety of the equipment and the personnel can be ensured.
9. Gradually swing the crank, if the pointer is at the zero position, stop swinging in case of coil damage.
10. When using decade high resistance box to test, while the generator is at its rated speed, use the following returning to zero method to avoid sudden short circuit in the terminal knobs.
Connect the resistance in order: M: 200 100 10 5 4 3 2 1 0
11. Avoid shaking in case of the damage of the gauge head axis tip or the diamond which might result in the failure of display value.
12. The tester should be stored at a temperature ranging from 0ºC to 40ºC under a corrosive gas free environment with the relative humidity less than 85%.
Electric Principle chart
G-generator
E-earthing
L-line
G-shielding
V-silicon rectifier diodes
C-capacitor
Ri- current coil limiting resistance
Rv- voltage coil limiting resistance
Li- current coil
Lv- voltage coil
Lv- balanced coil
LD- damper coilThe Complete Set
The product consists of:
1. ZC-7 Insulation Resistance Tester one piece
2. Instruction Manual one piece
3. Inspection Certificate one piece
4. Special Measure Traverse Line one piece