A Drives breakthrough on three levels

Yaskawa's new Varispeed G7 heralds the next generation of variable speed drive technology. The first general purpose inverter in the world to offer Three Level Control, the drive uses a radical new core technology.

The Varispeed G7 eliminates damaging micro surges caused by reflected voltage waves. The technology offers both smooth and stable performance at extremely low speeds, with a doubling of the open loop speed control range from 100:1 to 200:1. Open loop torque control has also been improved to 150% plus of motor FLT at 0.3Hz.
At low switching frequencies, this technology offers dramatic noise level reductions, including both radiated and audible noise. Noise levels have been reduced by 5dB, impressive when considering that 3dB noise reduction has the effect of halving the perceived noise level.

Further benefits of using the Varispeed G7 are reductions in motor bearing currents, RFI, EMI and leakage currents. Three Level Control makes it possible to use the Varispeed G7 on old or existing motors, without the need for output chokes, even on long cable runs.

Although this new technology might appear relatively expensive, its use enables a reduction in filter size and cost, in addition to extending motor life. The drive's high initial price is more than compensated for by its substantially lower operating costs.

Released: June 2002