Three circuit transformerDC resistance testerIt is an instrument used for simultaneous measurement of three-phase DC resistance of large capacity transformer windings. This instrument can simultaneously test the three-phase winding of transformers, and can directly adjust the tap of on load tap changers without the need for discharge. The testing time is only one-third of traditional methods, solving the problem of long testing time for DC resistance of power transformers. The instrument can automatically adjust the test current according to the different resistance of the transformer winding, allowing the instrument to test in state without manually switching the current gear, making it very easy to use.
However, due to the possibility of voltage on input and output terminals, test columns, etc., electric sparks may be generated when plugging and unplugging test wires and power sockets. Be careful of electric shock and avoid the danger of electric shock. The following is an explanation of the operation and faults of the three circuit transformer DC resistance tester.

DC resistance testerFault Analysis
1. As shown in Figure 14, the instrument displays the interface:
One or more phase display circuits are not connected.
Reason for malfunction: (1) The test wire is not properly connected or the clamp is not securely fastened.
(2) Instrument power failure.
At this point, you should first press the "return" button to discharge the positively charged winding, and then check the wiring.
2. No display when turned on:
Reason for malfunction: (1) The AC220V power supply is not connected.
(2) The fuse inside the AC220V power socket is damaged.
(3) The internal plugins of the instrument are loose.
3. Long term display of 'charging'
Reason for malfunction: (1) The test wire is not properly connected or the clamp is not securely fastened.
(2) Exceeding the testing scope.
(3) Instrument power failure.