Stand-alone device with wide power range

The SD4S product variant, where the S stands for stand-alone, kicks off Sieb & Meyer's new SD4x series. The frequency inverters succeed the successful SD2S models and are designed for stationary use in control cabinets of machine tools or turbo compressors/compressors.

The SD4S frequency inverter is currently available in 50 and 230 V class sizes, with additional 400 V class models coming to market in 2023. In total, these devices will then cover the current power range (1.4..55 kVA) of the SD2S series or even extend it downwards and upwards (0.8..66 kVA).

The SD4S provides PWM frequencies up to 32 kHz and commutation frequencies up to 64 kHz. This results in higher rotating field frequencies up to 6,000 Hz and lower harmonic frequency components. The user can realize higher-pole motor designs and benefits from lower motor losses. Another advantage is that the input for the thermal contact is galvanically isolated from the logic and main voltage. This ensures safe operation even in the event of an insulation problem of the thermal contact in the motor. Last but not least, the Motor Analyzer software tool allows simulation of the operating points and FFT analysis with THDi and THDu calculation. This means that system performance can be analyzed right from the start of development.

By the way: With the SD4S it is possible to optimally operate synchronous motors with "buried" magnets, also called Interior Permanent Magnet Motor (IPM). The additional reluctance torque available for these motors is optimized in real time, independent of the operating point.