Power supply
The transformer DC resistance tester provides two types of power supply for the test: AC 220V/DC 12V. In the case of strong electromagnetic field interference, it is recommended to use the DC power supply for the test. In this state, the test values are stable and have strong resistance to industrial frequency interference.
Charging:
Connect the AC 220V power supply. At this point, the “charging” indicator light comes on, indicating that the charging battery inside the instrument is undergoing charging. If the rechargeable battery inside the instrument has sufficient charge, the “full” indicator light will come on. While the instrument is using the AC power supply for testing, it is also charging the internal battery. (The instrument is designed with a charging protection circuit, so there will be no overcharging phenomenon.)
DC power supply test:
Close the power switch. 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. The “Discharge” indicator light will turn on (if the stored charge of the tested item is small, the “Discharge” indicator light will not turn on). After discharging, the “Discharge” indicator light will go out. Then switch to another test for another test.
Power supply test:
Connect the AC220V power supply. The corresponding indicator lights (“Charging” indicator light or “Fully Charged” indicator light) will light up. Close the power switch. The power indicator light will also 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. The “Discharging” indicator light will light up (if the stored charge of the tested item is small, the “Discharging” indicator light will not light up). After discharging, the “Discharging” indicator light will go out. Then switch the test clips and conduct another test.
The connection method of the test line
Connect the I+, V+, V-, and I- terminals of the transformer DC resistance tester to the test sample in accordance with the wiring diagram provided in the user manual. This connection method can eliminate the influence of contact resistance and wiring resistance on the measurement.
During use, if the test cable provided with the instrument is not long enough, you can use wires of the same diameter to extend the test cable.
Measurement
After connecting the test wires according to the wiring diagram in the transformer DC resistance tester manual, close the power switch. The power indicator light will turn on. Press the “Start/Stop” button. At this point, the meter displays “E0000″. Based on the size of the measured value, select the resistance range and range. Press the corresponding range switch. At this time, the indicator light of this range will be on, and the stable value displayed by the four-digit half-precision CD is the measured resistance value. When reading the value, please pay attention to the unit (m2/2k2) on the selected range.
When measuring large inductive test samples such as power transformers, it is advisable to short-circuit the coils that are not under test outside the test circuit to avoid electromagnetic interference.
Discharge
After the test is completed, the main power supply can be turned off directly. If testing a capacitive test sample, do not immediately disconnect the wires after turning off the power. The instrument should have a continuous discharge process. Generally, the discharge should last for at least 20 seconds; otherwise, the reverse electromotive force of the inductor may endanger personal safety.
Post time: Feb-24-2026