I. Insulation resistance meter powered by hand-cranked generator
1. It is forbidden to measure the insulation resistance during lightning or near high-voltage equipment, and the insulation resistance of the live equipment cannot be measured with the insulation resistance meter, otherwise the object to be tested or the insulation resistance meter will be damaged;
2. The insulation resistance meter should be placed in a stable and firm place and away from large external current conductors and external magnetic fields.
3. Correctly select the meter with the appropriate range for measurement. When measuring the insulation resistance of high-voltage equipment, the high-voltage insulation resistance meter should be used. Anyway, a low-voltage insulation resistance meter should be used.
4. There are generally three terminals on the insulation resistance meter, which are marked with L (line), E (ground) and G (shield) respectively. L is connected to the conductor part of the measured object and the earth, and E is connected to the measured object. The outer casing or the earth, G is connected to the shielding ring of the object to be tested.
5. The external connection of the insulation resistance meter should be a single insulated wire. It is not advisable to use double-stranded wires, and do not hinge the external wires together.
6. When using the insulation resistance meter, first check whether the meter itself leaks. The specific method is: check whether the ground wire and the “circuit†are short-circuited at both ends and the pointer is zero or infinity when the circuit is open; when measuring, shake the generator handle evenly. Generally, the reading is about 120r/min to be stabilized.
7. When measuring, the speed of the rocking handle should be slow to fast, and should be reached and stabilized at 100~140r/min. After the watch is stable, read the reading again, then the reading is correct.
8. When the measured object is a capacitive load, after the insulation resistance meter measures the reading, it is not appropriate to stop the rotation of the handle immediately, but should generally gradually reduce the speed, and the other side removes the wiring of the line end to avoid the insulation resistance table handle immediately stop rotating. After that, the insulation resistance meter is damaged due to the discharge of the capacitive load. In addition, the capacitive load should be drained before the measurement to achieve the uncharged operation.
9. When testing the insulation resistance of electrical equipment, the temperature and humidity during measurement should be recorded to analyze the measurement results.
10. Never touch the hand before the insulation resistance meter stops rotating or the device under test is not discharged. Do not touch the metal part of the lead when disconnecting the wire.
11. After the measurement is completed, the generator is stopped after the generator stops rotating, and the object to be tested is discharged locally.
Second, the battery-powered insulation resistance meter
When using this type of insulation resistance meter, you should pay attention to the following items:
1. Confirm that the tested object is safely grounded and the measured object is not charged.
2. Confirm that the E terminal (ground) of the instrument is grounded.
3. After the test is completed, please turn off the high voltage and working power in time. Always keep the exterior clean and wipe with a clean cloth if necessary. When the meter is not used for a long time, the battery must be taken out to avoid corrosion of the instrument, and the meter should not be exposed to moisture, rain, exposure or falling.
4. After the reading is completed, first press the button to turn off the high voltage, and the high voltage indicator is extinguished. Turn the power switch off by placing the function selector switch in the "ON" position. For capacitive loads, the residual charge on the tested part should be drained, and the test line should be removed to avoid electric shock.
5. When measuring the high insulation resistance value, a conductor protection ring should be placed on the surface between the two ends of the object to be tested, and the conductor protection ring should be connected to the protection terminal of the instrument with a test to eliminate the surface leakage of the object to be tested. The measurement error caused by the current ensures the accuracy of the test.
Incremental Encoder is commonly used, and Absolute Encoder is used if there are strict requirements on position and zero position. Servo system should be analyzed in detail, depending on the application situation. Commonly used incremental encoder for speed measurement, which can be used for infinite accumulation measurement; Absolute encoder is used for position measurement, and the position is unique (single or multiple turns). Finally, it depends on the application situation and the purpose and requirements to be realized.
Incremental Linear Encoders,Linear Optical Encoder,Linear Position Encoder,Encoder Bearing Tester
Yuheng Optics Co., Ltd.(Changchun) , https://www.yuhengcoder.com