To calibrate a clamp-on ammeter, follow these steps
The commonly used measuring instruments for electricians include shake meters, multimeters, and clamp ammeters. If these instruments are not used correctly or are slightly negligent during measurement, they will either burn out the meter, damage the tested components, and even endanger personal safety. Therefore, it is very important to master the correct use of commonly used electrician measuring instruments.
The shaking table, also known as a megohmmeter, is used to test the insulation condition of circuits or electrical equipment. The usage method and precautions are as follows: (1) First, choose a shaking table that is suitable for the voltage level of the tested component. For circuits or electrical equipment with a voltage of 500V or below, a shaking table with a voltage of 500V or 1000V should be used. For lines or electrical equipment above 500V, a 1000V or 2500V shake meter should be used.
(2) When testing the insulation of high-voltage equipment with a shake table, it should be done by two people.
(3) Before measurement, all power sources of the tested circuit or electrical equipment must be disconnected, that is, live measurement of insulation resistance is not allowed. And it can only be carried out after confirming that there is no one working on the circuit or electrical equipment.
(4) The wire used for shaking the watch must be insulated and double stranded insulated wire should not be used. The end of the wire should have an insulation sheath; The line terminal "L" of the shaking table should be connected to the measured phase of the equipment, the grounding terminal "E" should be connected to the equipment casing and non measured phase of the equipment, and the shielding terminal "G" should be connected to the protective ring or cable insulation layer to reduce measurement errors caused by insulation surface leakage current.
(5) Before measurement, open circuit calibration should be performed on the shaking table. Shake the shaking table when the "L" and "E" ends are unloaded, and the pointer should point to "∞"; When the "L" end and "E" end of the shaking table are short circuited, the pointer of the shaking table should point to "0". The shaking table function is good and can be used.
(6) Before testing, the tested circuit or electrical equipment must be grounded and discharged. When testing the circuit, permission from the other party must be obtained before proceeding.
(7) When measuring, it is advisable to shake the handle of the shaking table at a uniform speed of 120r/min; After maintaining a stable speed for 1 minute, take a reading to avoid the influence of absorbed current.
(8) During the testing process, both hands should not touch two wires at the same time.
(9) After the test is completed, the wires should be removed first, and then the shaking of the meter should be stopped. To prevent electrical equipment from reverse charging the shaking table and causing damage to the shaking table.
(10) It is strictly prohibited to test the insulation of the circuit during lightning strikes.
