Briefly describe the usage method of clamp watch
A clamp ammeter, also known as a clamp meter, is a specialized electrical instrument used to measure AC current. It is generally used in situations where the circuit is continuously opened to measure current. Currently, instruments with multifunctional digital display or pointer display are commonly used
The usage method of a clamp type ammeter is simple, as shown in the above figure. When measuring current, simply clip the running wire to be tested into the clamp type iron core of the clamp type ammeter, and then read the reading on the digital display screen or indicator panel. It's easy to use, isn't it,
Just clamp the measuring wire. However, with the widespread use of digital clamp ammeters nowadays, many functions of a multimeter have been added to the clamp meter, such as voltage, temperature, resistance, etc. (sometimes referred to as a clamp multimeter, as shown in the figure above, with two probe sockets on the instrument). Different functions can be selected by turning the knob, and the usage method is similar to a typical digital multimeter. For the meanings of some unique function buttons, the corresponding instructions should be referred to.
In addition, when using a clamp type ammeter, the following issues should be noted:
1. Select an appropriate range range and do not use a small range to measure large currents. If the measured current is small, the current carrying wire can be wound several more times and placed in the clamp for measurement. However, the actual current value should be determined by dividing the reading by the number of coils wound. After the measurement is completed, the adjustment switch should be placed in the maximum range position (or closed position) for safe use next time.
2. Do not switch the range during the measurement process.
3. Note that the voltage on the circuit should be lower than the rated value of the clamp ammeter. Clamp ammeters should not be used to measure the current of high-voltage circuits, otherwise it may cause accidents or electric shock hazards.
Firstly, select the voltage level of the clamp type ammeter correctly, check its appearance for good insulation, damage, flexible pointer movement, and rust on the jaw. Estimate the rated current based on the motor power to select the range of the meter.
When measuring, the jaws of the clamp type watch should be tightly closed. If there is any noise after closing, the jaws can be opened and reset once. If the noise cannot be eliminated, the joint surfaces on the magnetic circuit should be checked for smoothness. If there is dust, it should be wiped clean.
The clamp meter can only measure the current of one phase wire at a time, and the measured wire should be placed in the center of the clamp window. It is not allowed to clamp all multiphase wires into the window for measurement.
The voltage of the tested circuit should not exceed the value indicated on the clamp meter, otherwise it may cause grounding accidents or electric shock hazards.
Before using a clamp type ammeter, it is necessary to carefully read the manual and determine whether it is an AC or DC dual purpose clamp type ammeter.
Due to the low accuracy of the clamp ammeter itself, the following method can be used when measuring small currents: first, wrap the wires of the circuit being tested a few turns, and then place them in the clamp of the clamp ammeter for measurement. At this point, the current value indicated by the clamp meter is not the actual value being measured, and the actual current should be the reading of the clamp meter divided by the number of coils wound on the wire.
Measure the working current of the cage asynchronous motor during operation. Based on the current level, it is possible to check and determine whether the motor is working properly to ensure safe operation and extend its service life.
