Common faults and solutions of ammeters
Clamp type ammeters are divided into 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 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.
The solution to clamp ammeter
(1) When measuring current or voltage, there is one or several levels without indication, while other levels indicate normal. The reason is that the fastening switch screw of the clamp 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. The jaws should be corrected to ensure good contact. This type of fault is sometimes caused by short circuits between windings, which can be quite troublesome. Generally, it is necessary to rewind according to the original data and undergo aging treatment.
(3) The readings of the current and voltage levels are all low, which often occurs on internal magnetic clamp type meters. The reason is demagnetization of the magnet, which should generally be solved by magnetization. It can also be adjusted by reducing the resistance value connected in series with the meter head branch.
(4) If one of the readings is inaccurate, the corresponding resistance should be adjusted.
(5) The voltage level indication is normal, but there is no indication for the current level. 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
