MV Motor Soft Starter

RXHK has developed an innovative variable frequency starter (VFS) technology for soft start and soft stop applications. It achieves discrete frequency conversion and step-less voltage regulation through thyristor control. Start and stop control methods range from voltage inclination start to constant current start and soft stop to braking stop. Starters are precisely tailored to suit a machine’s load behaviour.

Our VFS technology can be applied to the soft start and soft stop of blowers, pumps, compressors and other high voltage three-phase AC induction motors or synchronous motors. It can also be used in applications requiring fixed frequency conversion speed regulation.

RXHK's Static Frequency Converter is based on a full control power device (4500V PP-IGBT), adopting power cells cascade technology to directly output high voltage levels. In each phase we link between 2 to 6 power cells to deliver an output between 6kV an 16.5kV or even higher voltage level. In this way there is then no need for any step-up transformer and the system structure can be simple.

Compared with LCI technology (based on thyristor devices), the RXHK VSI drive solution has the advantages of

1. high network power factor, friendly network side and motor side waveforms, no need for any input side or output side filters;
2. quick dynamic response and can start high inertia loads with the same drive capacity;
3. directly output high voltage level, no need for any step-up transformer and
4. much higher system efficiency because of the simplest system structure;

Technical details

RXHK’s MV motor soft starters can output 0-60Hz frequencies. They achieve a lower starting current with higher starting torque by controlling the voltage-frequency ratio of the motor.

Technical parameters

Applications