working principle:

The relay protection test instrument is divided into two circuits, the main circuit and the auxiliary circuit. The main circuit is adjusted by a large knob, and the auxiliary circuit is adjusted by a small knob. The main circuit is controlled by the "output selection" key switch on the panel to control various output quantities, and When each output is switched, the digital voltage/current meter on the instrument can automatically monitor its output value. The auxiliary circuit is controlled by the output switch to directly adjust the output, and the measurement can be measured by an external multimeter.

Principle of main circuit

The input AC220V power supply enters the T1 input terminal of the dual carbon brush voltage regulator through the output control relay K1 through the insurance, and the power adjusted by the T1 large knob enters the isolation transformer T2 (part-time current booster). The current booster has three taps for output, one The tap is AC0-250V output, and the rated current is 3A; the output voltage of this tap can output 0-350V DC voltage after rectification and filtering; the second one is 15V (10A), and the tap is controlled by the sensor to output 0-10A all the way through a relay. AC current, one way outputs 0-500mA AC current through resistance, one way can output 0-10A or 0-500mA DC current through relay conversion; the second tap is 10V (100A) high current end, this tap passes directly through the primary side of the sensor Output 100A current, the circuit has a strong load capacity, but the output is slightly overloaded, and it cannot be in a high current state for a long time. Thermal relay calibrator

Principle of Auxiliary Circuit

The auxiliary circuit of the relay protection test instrument is the same as the main circuit. The AC220V power supply is insured and enters the voltage adjusted by the small knob of the double carbon brush voltage regulator T1. The isolation transformer T4 can directly adjust the output 0-20V or 0-250V AC voltage or 0 -350V DC voltage, the rated current of this loop is 1A. Press the "output control" switch of the auxiliary circuit and adjust the small knob to output.

Principle of Measuring Circuit

The output of the main circuit adjusted by the large knob is AC "0-250V", "0-500mA", "0-10A", "0-100A", DC "0-350V", "0-500mA", "0- 10A" is converted by the relay on the circuit board in the equipment, and each time a gear is switched, the corresponding output can be monitored. The "0-500mA" file is included in the "0-10A" file. When in use, two clicks of "0-10A" are "0-500mA" monitoring.

Time measurement principle

The device has a built-in 6-digit display stopwatch, and the electric stopwatch can be started internally or externally. When internally starting, press the "output control" switch to start the stopwatch, and to stop the stopwatch by short-circuiting the stopwatch terminal on the device panel through the contact. The stopwatch is equipped with a separate power switch, and the stopwatch can be turned off when not in use.