Working principle of clamp ammeter and precautions for use
The clamp ammeter is made based on the principle of the current transformer. Its shape is like a pliers. When the wrench of the clamp ammeter is grasped, the iron core of the current transformer can be opened, and the wire of the measured current enters the inside of the jaw as When the primary winding of the current transformer is closed by loosening the wrench core, an induced current will be generated in its secondary winding according to the principle of the current transformer, and the pointer of the ammeter will deflect, indicating the measured current value.
Correct use and precautions of clamp ammeter
(1) The clamp ammeter generally uses a switch to change the measurement limit. The current limit has four levels: 5A, 1OA, 50A, and 250A; the voltage limit has two levels: 300V and 600V. When the measured current is less than 5A, in order to obtain a more accurate reading, if conditions permit, the wire can be wound a few times and put into the jaws for measurement. The actual current value is the meter reading divided by the wire roots put into the jaws. number.
(2) When measuring AC current, place the measuring wire in the middle of the jaws and close the jaws tightly.
(3) The clamp ammeter should be kept in a dry room and wiped clean before use.
(4) There should be two people conducting the measurement, one measuring and one supervising.
(5) The voltage of the circuit under test must not exceed the specified value marked on the clamp ammeter. Otherwise, the insulation strength of the meter is insufficient, which may easily cause a grounding accident or the risk of electric shock.
(6) Wear insulating gloves when measuring, stand on an insulating pad, and do not touch other equipment to prevent short circuit or grounding. Observe the timing of the watch and be careful to keep a safe distance between your head and live parts.
(7) It is not allowed to switch the current limit switch during the current measurement process to avoid damaging the instrument; when necessary, the clamp ammeter should be removed from the wire.
(8) Only one wire can be clamped for each measurement, and two or three wires cannot be clamped at the same time.
