Zhengzhou Protech
Home > News >

Disadvantages of solid state relay of muffle furnace thermostat

Disadvantages of solid state relay of muffle furnace thermostat:
muffle furnace
        (1) The voltage drop of the tube after the turn-on is large, the forward voltage drop of the thyristor or two-phase thyristor can reach 1~2V, and the saturation voltage drop of the high-power transistor is also between 1~2V, general power field effect The on-resistance of the tube is also larger than the contact resistance of the machine.
        (2) After the semiconductor device is turned off, there can still be a few microamperes to a few milliamperes of leakage current, so the ideal power interruption cannot be completed.
        (3) Because of the large pressure drop of the tube, the power consumption and fever after being turned on are also large. The volume of the high-power solid-state relay is far greater than the electromagnetic relay of the same capacity, and the cost is also higher.
        (4) The temperature characteristics of electronic components and the anti-interference ability of the electronic route are poor, and the radiation tolerance is also poor. If you do not adopt useful steps, the reliability of things is low.
        (5) Solid state relays have greater inertness to overload, and must be protected against overloads with fast fuse or RC resistance circuit. The load of the solid state relay is closely related to the ambient temperature, and the temperature decreases, and the load capacity will quickly decrease.
        (6) The important shortcomings are the on-state voltage drop (need to respond to the heat dissipation step), off-state leakage current, AC and DC are not universal, the number of contact groups is small, other overcurrent, overvoltage, voltage recovery rate, current recovery rate Wait for the goal to be bad.