The Hitachi SJ300 is a sensorless flux vector inverter that is small in size and in open loop mode delivers 150% torque at 0Hz and greater than 200% torque at 0.5Hz.

At the heart of the SJ300 lies a new state of the art power module that uses Trenchgate technology developed in Japan. This new technology achieves 20-30% lower losses than traditional IGBT's at 50% higher current density.

The technology centres on advanced new control algorithms that can be processed using Hitachi's own new 32-bit RISC processor.

The SJ300's vector control algorithm differs from the previous J300 method in that the new program uses slip frequency together with real, rather than assumed voltage values, to make its control calculations. This has resulted not only in full torque at 0Hz but a significantly improved speed resolution of an impressive ±0.5%.

Other unique features of the SJ300 include:

• On-line Autotuning with compensation for the changing electrical characteristics of the motor as it warms with use.
• Contolled braking, fieldbus compatibility, feedback card for closed loop control.
• PLC functionality and interface with Hitachi's own EH-150 PLC.
• Removable I/O terminals, DC bus capacitors and cooling fans for ease of installation and maintenance.
• Automatic energy saving mode with kWh consumption recording.