Usage and precautions of clamp Ammeter
Clamp type Ammeter (clamp meter for short) is an instrument integrating current transformer and Ammeter. Its working principle is the same as that of measuring current with current transformer. Clamp type meter is a combination of current transformer and Ammeter. After tightening the wrench, the core of current transformer can be opened, and the wire for measuring current can pass through the opening gap of the core without being cut. After loosening the wrench, the core can be closed, The conductor passing through the core wire of the circuit under test becomes the primary coil of the current transformer, and the current is induced in the secondary coil through the current. Therefore, the Ammeter connected to the secondary coil has the function of indicating - measuring the current of the circuit under test.
Clamp type Ammeter is divided into high voltage and low voltage, which is used to directly measure the current in the line without disconnecting the line. Its usage is as follows:
1. When using a high-voltage clamp type meter, please pay attention to the voltage level of the clamp type Ammeter. It is strictly prohibited to use a low-voltage clamp type meter to measure the current of the high-voltage circuit. When using a high-voltage clamp type meter for measurement, it should be operated by two people. The non on duty personnel should also fill in the second type 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.
When one phase of the cable is grounded, measurement is strictly prohibited to prevent personal safety hazards caused by low insulation level of the cable head due to grounding faults.
3. After the clamp Ammeter is measured, pull the switch to the maximum range to avoid accidental overcurrent during next use, and store it 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 should not be less than the entire length of the clamp type meter.
5. When measuring on the high-voltage circuit, it is forbidden to use wires to measure from another 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 more than 300mm, and the insulation should be good. It can only be carried out when it is considered convenient to measure.
When measuring the current of low-voltage fuses or horizontally arranged low-voltage busbars, each phase of the fuses or busbars should be protected and insulated with insulating materials before measurement to avoid phase to phase short circuits.
