The usage methods and techniques of clamp ammeters
A clamp type ammeter consists of a current transformer and an ammeter. It is an instrument used to measure the current level of an operating electrical circuit, and can measure AC current without interruption.
Usage of clamp ammeter
1. Pre test preparation:
Take a look at the pliers. The jaws of the instrument should be clean. If there are debris or oil stains, they should be cleaned in a timely manner to ensure that the magnetic circuit is strictly closed and the measurement results are accurate.
Look at the pointer. Observe the position of the pointer, and if it is not at zero, perform a mechanical zero adjustment.
2. Measurement steps:
The first step is to select the range
Firstly, estimate the magnitude of the measured current and adjust the transfer switch to the desired measurement position. If it is impossible to estimate the magnitude of the measured current, first use the highest range range for measurement, and then adjust to the appropriate range according to the measurement situation.
Step 2: Opening and wiring
The key to operation is to grip the handle tightly, open the jaws, and place the measured wire. To reduce errors, the measured wire should be placed in the center of the jaws.
Step 3: Closed mouth reading
Release the handle, and the jaws will naturally return to a close contact state. After the pointer stabilizes, read the display number. If there is noise, check if the jaws are in close contact or operate again.
Step 4: Opening Offline
Grip the handle tightly and open the jaws to allow the clamp gauge to move away from the wire. After the measurement is completed, turn the range selection switch to the maximum range position.
3. Precautions:
The voltage of the tested circuit should be lower than the rated voltage of the clamp ammeter.
When measuring the current of high-voltage lines, it is necessary to wear insulation gloves, shoes, and stand on insulation pads.
3) The jaws should be tightly closed and cannot be switched to a range with electricity.
4) The range should be selected appropriately. When selecting a range, one should first select the large range, then select the small range or estimate the nameplate value.
5) Place the wire in the center of the jaws.
6) After the measurement is completed, the transfer switch should be placed at the closest range.
4. Measurement techniques:
When measuring small currents below 5A, in order to improve measurement accuracy, if conditions permit, the measured wire can be wound a few more turns and then placed in the clamp for measurement. At this point, the actual current should be the instrument reading divided by the number of wire turns placed in the clamp.
