New drive is most advanced AC inverter yet

Yaskawa's next generation of advanced variable speed drives is manifest in the new Varispeed F7 AC inverter. The F7 features sensorless flux vector current control and incorporates a number of new features which are not found in any other drives to date. It can also be configured for standard V/F control.

The company has been able to significantly reduce the acoustic noise at low carrier frequencies, leading to a quieter Motor and Drive combination. There is an automatic energy saving function which is likely to win considerable favour under the soon to be imposed Climate Change Levy. Improved PID control makes the drive a versatile process and automation tool. The F7 also employs Yaskawa's unique high slip braking technique which enables periodic and emergency braking without the need for brake units or braking resistors. Finally, in Japanese tradition, the drive is substantially smaller, cheaper and longer lasting than any previous inverter!

There are differences in the hardware of the new drive. For instance, removable control terminals have been incorporated to make installation and servicing much simpler. A DC reactor is built in to all drives from 22kW upwards, reducing installed costs and reducing the size of the drive. The drive uses 4th generation IGBT technology for its solid state switching and also has improved short circuit protection. The unit has a motor thermistor monitor capability and on/off control of the cooling fan extends working life.

In software, the latest developments enable the user to select between auto tuning in non-rotating mode or under load in a dynamic routine. New speed search facilities have enabled better capability to catch a spinning motor in either direction, for instance in extraction fan applications where the fan may be contra rotating under air movement on start up. There are also new software functions that enable a PID "sleep" function and low torque detection levels to be set. Programming the new F7 is simple, on or off line, and is made easier by the built in Parameter Unit featuring a 'copy function'. Programming functions can be extended through the use of Yaskawa's proprietary application specific software and a further optional extra is a seven-language LCD operator panel.

All models support RS424/485 communications, DeviceNetTM and Profibus-DPTM as standard. Option cards are available for Interbus-STM, CANopenTM and CC-link field networks.
Yaskawa has designed the F7 to be a universal quick start drive spanning fan and pump and open loop vector inverter applications. In all instances the new model is extremely cost effective. The range is covered by global certification for CE, UL and ULc. The Yaskawa F7 ranges from 0.4 to 300kW at 400V, and 0.4 to 110kW at 200V.

Released March 2001