How to replace and adjust the high temperature electric furnace thyristor?

Replacement To replace the thyristor unit, first isolate the high-temperature electric furnace from the power supply, and then remove the left side cover (0). Record all connections to the thyristor, and then disconnect it. Replace the device, and then rewire.

Note: If you change the 208V power supply, you need to replace the thyristor unit.

If the thyristor unit is replaced due to a voltage change, the correct transformer tap adjustment should also be set. After replacing any thyristor unit, or after changing the voltage or transformer tap, the potentiometer on the thyristor must be adjusted to provide the correct components Current. This operation should be carried out by qualified personnel, because dangerous voltages exist in the control room.

In addition, a calibrated non-intrusive clamp ammeter is required. Before connecting the power supply, turn the potentiometer on the thyristor to the left (counterclockwise). This sets the output current of the thyristor to “off”. Connect the power when closing the side cover. Beware! Set the furnace temperature to a large value. Let the stove begin to heat up. Measure the current through the component circuit. When measuring, use the thick pair of cables on the left side of the transformer to wind the clamp ammeter. Adjust the potentiometer located on the surface of the thyristor unit. Slowly adjust to the right (clockwise) to increase the current, and pause to make the ammeter respond.

Continue to adjust so that the ammeter reading is between (149 to 150 A-for HTF 17) or (139 to 140A-for HTF 18). This adjustment should be made within the first 5 minutes of heating, and the final test should be carried out when the temperature of the high-temperature electric furnace is lower than its high temperature by about 100°C. If necessary, continue to adjust under this temperature condition. Disconnect the power supply and make sure to replace the side panel.