Explanation of the method and precautions for measuring current with a clamp meter
Clamp meter is an instrument that combines current transformers and ammeters, and is an important branch of digital multimeter; It is a portable instrument that can directly measure the AC current of a circuit without disconnecting the circuit. A clamp meter is essentially composed of a current transformer, a clamp wrench, and a rectifier magneto electric system reactive force instrument.
usage method:
(1) Mechanical zeroing is required before measurement
(2) Choose the appropriate range, first choose the large range, then choose the small range or estimate the nameplate value.
(3) When using the minimum range measurement and the reading is not yet clear, the measured wire can be wound a few turns. The number of turns should be based on the number of turns in the center of the clamp, and the reading=indicated value x range/full deviation x number of turns
(4) After the measurement is completed, place the conversion switch at the maximum range.
(5) When measuring, the measured wire should be placed in the center of the clamp and the clamp should be tightly closed to reduce errors.
matters needing attention:
(1) When using a high-voltage clamp meter, attention should be paid to the voltage level of the clamp ammeter. It is strictly prohibited to use a low-voltage clamp meter to measure the current of the high-voltage circuit. When using a high-voltage clamp meter for measurement, it should be operated by two people. Non duty personnel should also fill out the second type of work permit. When measuring, they should wear insulated gloves, stand on insulated pads, and not touch other equipment to prevent short circuits or grounding.
(2) When observing the timing of the watch, special attention should be paid to maintaining a safe distance between the head and the charged part. The distance between any part of the human body and the charged part should not be less than the entire length of the clamp watch.
(3) When measuring on a high-voltage circuit, it is prohibited to connect wires from a clamp ammeter to another meter for measurement. When measuring the current of each phase of high-voltage cables, the distance between cable heads should be at least 300mm, and the insulation should be good. It can only be carried out when it is considered convenient for measurement.
(4) When measuring the current of low-voltage fusible fuses or horizontally arranged low-voltage busbars, each phase of the fusible fuse or busbar should be protected and isolated with insulation materials before measurement to avoid causing phase to phase short circuits.
(5) It is strictly prohibited to measure when one phase of the cable is grounded. To prevent ground breakdown and explosion caused by low insulation level of cable heads, which may endanger personal safety.
(6) After the clamp ammeter measurement is completed, turn the switch to the maximum range to avoid overcurrent during the next use; And should be stored indoors in a dry place.
