UK-developed digital DC drive `speaks English`

Sprint Electric has made "a major investment" to develop its first range of digital DC drives. The company, which is manufacturing the PLX drives at its Arundel, West Sussex base, asserts that they are "the most powerful, flexible and easy to programme" on the market.

When programming the drives, every parameter is specified using English words rather than codes. To minimise the need for external hardware, application software functions needed to perform complex tasks are built in.

The drives are being produced in two- and four-quadrant versions in three frame sizes, with power ratings from 5-50kW, 65-145kW and 185-265kW. The two-quadrant versions offer regenerative braking.

Programming is done using "application blocks". A configuration checker detects whether any of the block diagram outputs are shorting.

The drives` 40-character backlit LCD readout can be used for diagnostics and will show key parameters in engineering units, avoiding the need for external meters. There is also an "oscilloscope" output to allow parameters to be monitored during commissioning.

Protection is provided against a variety of conditions including overcurrents, field failures, phase losses, armature overvoltages, output short circuits and thyristor trigger failures. A non-volatile memory stores trip alarms even after a power loss.

Five feedback transducer options are offered and the field is fully controllable. According to Sprint, most types of motor and methods of operation can be used without needing extra boards.