Working principle of water resistance cabinet

Working principle: a special electrolyte is inserted in series into the rotor circuit of the wound motor as the resistance. By adjusting the concentration of the electrolyte and changing the distance between the two polar plates, the value of the series resistance always meets the requirements of the mechanical characteristics of the motor for the series resistance value during the starting process, so that the motor can speed up evenly and start smoothly under the condition of obtaining the maximum starting torque and the minimum starting current. After starting, the electrical switch is short circuited to the rotor circuit.

Operation principle: when the motor switch cabinet is closed, the water resistance cabinet receives the operation signal of the vacuum circuit breaker, and the moving plate starts to operate from top to bottom. The resistance value gradually decreases within the set time. When the resistance is close to zero, the vacuum contactor installed in the water resistance cabinet pulls in, and the motor starts. After a few seconds of delay, the moving plate automatically resets to the original state, waiting for the next start. If the water resistance cabinet is not started within the scheduled time, a fault alarm signal will be sent to automatically cut off the switch cabinet to ensure that the motor is not open circuit.

The liquid resistance starting cabinet is mainly composed of the following parts: water tank, pole plate (transfer pole plate and static pole plate), transmission mechanism, limit mechanism (travel switch) and related electrical components, such as relays (or PLC), time relays, contactors, buttons, indicator lights, etc. it is mainly applicable to 400V, 3KV, 6kV and 10KV voltage levels, Compared with other starting methods such as frequency sensitive resistor, frequency converter and reactor, the smooth soft start of wound AC asynchronous motor and low-voltage squirrel cage AC asynchronous motor with a power range of 500kw-30000kw has the characteristics of high starting power factor (due to resistive load), low cost and simple maintenance. It can limit the starting current of the motor to 1.3 times of the rated current at least, effectively reducing the impact of motor starting on the power grid, Therefore, it has been widely trusted by users in recent years.

Post time: Jun-20-2022