How to use clamp ammeter and precautions
Clamp-type ammeter (referred to as clamp meter) is an instrument that integrates a current transformer and an ammeter. Its working principle is the same as that of measuring current with a current transformer. A clamp-on meter is a combination of a current transformer and an ammeter. Tighten the wrench Finally, the core of the current transformer can be opened, and the wire for measuring the current can pass through the opening gap of the core without being cut off. After the wrench is released, the core is closed, and the wire passing through the core wire of the circuit under test becomes a current transformer. The primary coil, and the current is induced in the secondary coil by the current, therefore, the ammeter connected to the secondary coil has an indication-measurement of the current of the circuit under test.
Clamp type ammeter is divided into high voltage and low voltage, used to directly measure the current in the line without disconnecting the line, it is used as follows:
1. When using a high-voltage clamp meter, please pay attention to the voltage level of the clamp ammeter. It is strictly forbidden to use a low-voltage clamp meter to measure the current of a high-voltage circuit. When using a high-voltage clamp meter for measurement, it should be operated by two people, not on duty Personnel should also fill out the second type of work ticket, during the measurement, they should wear insulating gloves and stand on the insulating mat, they should not touch other equipment to prevent short circuit or grounding.
2. When one phase of the cable is grounded, it is strictly forbidden to measure to prevent the danger of personal safety caused by the low insulation level of the cable head due to the grounding fault.
3. After the measurement of the clamp ammeter is completed, pull the switch to the maximum range to avoid accidental overcurrent during the next use, and it should be stored in a dry room.
4. Observe the instrument, and pay special attention to maintaining a safe distance between the machine head and the charged part. The distance between any part of the human body and the charged body must not be less than the entire length of the clamp meter.
5. When measuring on a high-voltage circuit, it is forbidden to use wires to measure from another meter of the clamp ammeter. When measuring the current of each phase of the high-voltage cable, the distance between the cable head and the wire should be greater than 300mm, and the insulation should be good. It should only be performed when the measurement is considered convenient.
6. When measuring the current of low-voltage fuses or horizontally arranged low-voltage busbars, each phase of the fuse or busbars should be protected and insulated with insulating materials before measurement to avoid short-circuit between phases.
