Today it is common speed control of three-phase squirrel cage motors and three-phase synchronous motors using a variable frequency drive (VFD). The AC frequency and inverter output voltage determines the motor speed and can be adjusted independently of the mains voltage.
In operating conditions in which the electric machine operates as a generator (for example, when driving downhill, or braking), the energy generated by the motor causes increased voltage on the DC bus of inverter. To prevent damage to the components, the DC voltage must stay below a specified critical value.
In those cases in which the regeneration of energy to the grid will not be economical or not justify further investment, the extra energy produced by a braking maneuver, is converted to heat by a chopper and dynamic braking resistor.
A further variant is to use three-phase braking resistor in direct combination with the motor. Therefore, the resistance is connected via a contactor in the motor circuit. The motor windings are short-circuited in a controlled manner using resistors. This mechanism is extremely robust to ensure braking action independent of the chopper unit of the DC intermediate circuit. This system is often used for the emergency stop function of a machine.
Thanks to his extensive experience in this field, acquired over a period of many years, Frizlen will gladly advise you on the correct configuration of the dynamic braking resistor. Here, we can offer the optimum technical and economical solution with our diverse product portfolio.
- Oil and gas
- Wind turbines
- Cement industry
- metalworking indust
Tubular cemented wirewound resistor, resistor design one to three tubes, IP20 enclosure, mounting on a suitable surface with side panels and perforated cover. Parallel to the mounting surface fixing.
- 65 – 3000 W