Common faults of clamp ammeters
Clamp type ammeters are divided into two types: high and low voltage, used to directly measure the current in the circuit without disconnecting the circuit. The usage method is as follows:
(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 ticket for measurement. During measurement, insulation gloves should be worn, standing on insulation pads, and other equipment should not be touched 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 the cable heads should be at least 300mm, and the insulation should be good. Only when the measurement is considered convenient can it be carried out.
(4) When measuring the current of low-voltage fusible fuses or horizontally arranged low-voltage busbars, each phase of fusible fuses or busbars should be protected and isolated with insulation materials before measurement to avoid causing phase to phase short circuits.
(5) When one phase of the cable is grounded, measurement is strictly prohibited. To prevent the occurrence of ground breakdown and explosion due to the low insulation level of the cable head, which may endanger personal safety.
(6) After the measurement of the clamp ammeter is completed, turn the switch to the maximum range position to avoid accidental overcurrent during the next use; And should be stored indoors in a dry place.
The Solution of Clamping Ammeter
(1) When measuring current or voltage, there is one or several gears with no indication, while other gears have normal indications. The reason is that the fastening switch screw of the clamp type electric meter is loose, or the wiring on its branch switch is twisted and broken. This type of fault is the most common, just connect the broken wire after opening the cover.
(2) The current reading is too low, while the voltage reading is normal. The reason for this is mostly due to poor contact between the jaws and excessive magnetic leakage. It is necessary to correct the jaws to ensure good contact. This type of fault is sometimes caused by a short circuit between windings, which can be quite troublesome. Generally, it is necessary to rewind according to the original data and undergo aging treatment.
(3) The reading of current and voltage ranges is low, which often occurs on internal magnetic clamp type meters. The reason is that the magnet demagnetizes and should generally be magnetized to solve the problem. It can also be adjusted by reducing the resistance value in series with the meter branch.
(4) If one of the readings is inaccurate, the corresponding resistance should be adjusted.
(5) The voltage level indication is normal, but all current levels are not indicated. Use a multimeter to check the primary switch and secondary winding for any abnormalities.
(6) No indication at all. The rectifier diode, meter head, switch, and wiring connected to or related to the clamp meter should be checked for any breaks
