How to operate the DC resistance tester

DC resistance testerHow to operate it? The DC resistance tester has a wide range of applications in the power testing industry. It can measure the DC resistance of various inductive loads such as power transformers, large motors, and transformers, as well as the contact resistance of low-voltage switches, wire and cable or weld interface resistance. With powerful functions and relatively cheap prices, it is a multifunctional power testing instrument loved by many power workers. Taking the YTC316-10 DC resistance tester as an example, let me briefly introduce how to operate the DC resistance tester.

1. Power supply

There are two types of power supplies provided by the DC resistance tester: AC220V/DC12V. In the case of strong electromagnetic field interference, it is recommended to use a DC power supply for testing. The values tested in this state are stable and have strong resistance to power frequency interference.

A、 DC power supply test:

Close the power switch and the power indicator light will turn on. Press the "start stop" button to select the corresponding resistance gear switch for testing. After the test is completed, press the "start stop" button, and the "discharge" indicator light will turn on (if the stored power of the test sample is small, the "discharge" indicator light will not turn on). After discharge, the "discharge" indicator light will turn off, and then switch the test clip for another test.

B、 AC power test:

Connect the AC 220V power supply, and the corresponding indicator light ("charging" indicator light or "fully charged" indicator light) will light up. Close the power switch, and the power indicator light will light up. Press the "start stop" button to select the corresponding resistance gear switch for testing. After the test is completed, press the "start stop" button, and the "discharge" indicator light will turn on (if the stored power of the test sample is small, the "discharge" indicator light will not turn on). After discharge, the "discharge" indicator light will turn off, and then switch the test clip for another test.

C. Charging:

Connect the AC 220V power supply, and the "charging" indicator light will turn on, indicating that the charging battery inside the instrument is being charged. If the rechargeable battery inside the instrument has sufficient power, the "fully charged" indicator light will turn on. The instrument is charging the internal battery while using AC power for testing. (The instrument is designed with a charging protection circuit to prevent overcharging.)

2. Connection method of test line

Connect the I+, V+, V -, and I - terminals of the instrument to the test sample according to the method shown in Figure 1. This connection method can eliminate the influence of contact resistance and wire resistance on measurement.

Wiring of DC resistance tester

wiring diagram

In use, if the length of the test wire that comes with the instrument is not sufficient, a wire with a diameter equivalent can be used to extend the test wire.

3. Measurement

After connecting the test line according to Figure 2, close the power switch and the power indicator light will turn on. Press the "start stop" button, and the meter will display "E0000". Select the resistance range according to the size of the measured value, press the switch for that range, and the indicator light for that range will light up. The stable value displayed on the four and a half digit LCD is the measured resistance value. When reading the value, please pay attention to the units (m Ω/Ω/k Ω) on the selected range. When measuring large inductance samples such as power transformers, short-circuit other coils outside the testing circuit that do not require measurement to avoid electromagnetic interference.

4. Discharge

After the test is completed, the main power can be directly turned off. If it is an inductive test sample, the wire should not be disconnected immediately after turning off the power, and the instrument should have a continuous discharge process. Generally, discharge for at least 20 seconds, otherwise the back electromotive force of the inductor may endanger personal safety.

The operation method of the DC resistance tester produced by each manufacturer is different. In the actual operation process, power workers need to strictly follow the product manual of the instrument in their hands for wiring and operation, only in this way can the testing accuracy be achieved.