For conveyor belt, hoist machine, fan, water pump used for cement, mine, power plant, oil field or other required motor speed regulation.



Four-quadrant frequency conversion speed-adjusting cabinet main-circuit connection

Four-quadrant frequency conversion speed-adjusting cabinet main-circuit connection


Take four-quadrant for example, the frequency conversion speed-adjusting cabinet is made up of shell, frequency converter, knife fuse switch, charging resistor, compensation capacitor, Dv/Dt filter, input reactor, control transformer and contactor. It is compact in structure, stable in performance and convenient in usage and operation.

Frequency converter:

The heart of the whole frequency conversion speed-adjusting cabinet, when motor is in operation, three phase power supply, through rectification and inverter circuit, converts three-phase power frequency AC supply into direct current by means of PWM, and then through PWM again, the direct current is converted into three-phase AC supply whose frequency is continuously adjustable; when motor is in power generation condition, four-quadrant frequency cabinet will regenerate the electrical energy produced by the motor feedback to the electric network so as to conserve energy. Single quadrant frequency cabinet, on the other hand, connect braking resistor with DC-BUS and consume the electric energy regenerated by the motor in the form of heat energy, so as to realize stable and sound braking and ensure stable operation of the motor.

Electric reactor:

Install beside power supply line, so as to mitigate the interference of the power harmonic, improve power factor of the frequency converter, the periodic circuit connecting compensation capacitor and resistance formed during regeneration, and to reduce the interference of power harmonic in power supply.

Knife fuse switch:

Provide short circuit and over current protection for main circuit power supply.

Control transformer:

Provide AC220V power supply for the auxiliary circuit of frequency cabinet.

Brake unit:

For Single quadrant, when motor decelerates or brakes and is in power generation condition, the electric energy it produces, through inverter unit, will produce direct current voltage on DC-BUS; if the direct current voltage is higher than the threshold voltage on brake unit which is in operation, the braking resistor will consume the electric energy regenerated by the motor in the form of heat energy.


  • Introduce advanced vector control technology and closed-loop control technology as well as torque control technology.
  • Initiate the fine characteristics of smoothness of the torque, which has strong overload capacity.
  • Perfect and complete protective functions against overpressure, undervoltage, overcurrent, overload, momentary power failure, short circuit, input or output open-phase and temperature, etc.
  • Clear display function, which can show various parameters and error codes when the frequency conversion speed-adjusting cabinet is in operation.
  • Friendly human-computer interface, through hand-board, you can easily control the frequency conversion speed-adjusting cabinet to realize each of its functions.
  • Frequency conversion speed-adjusting cabinet is provided with convenient external control wiring, which can be connected with the control console or other control devices so as to realize the remote operation of the frequency conversion speed-adjusting cabinet.
  • Abundant flexible input, output interface and control mode. Strong commonality.