CONTROL TECHNIQUES Servo Drive

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Variable Speed Drive – Control Techniques SP1403

The SP1403 is a variable speed drive (“Variable Speed Drive / Servo Drive”) from the Unidrive SP family manufactured by Control Techniques, documented in service on CNC machine tools, machining centres and industrial automation systems requiring precise control of asynchronous or synchronous motors. The Unidrive SP (“Universal Drive”) family supports open-loop, RFC (Rotor Flux Control) and servo modes with encoder feedback, managing the complete speed/torque regulation chain from the DC-bus rectifier stage through the IGBT inverter output. The unit integrates short-circuit, over-temperature and overvoltage protection, and is expandable with optional fieldbus communication and advanced encoder input cards.

The drive is the device that converts mains electrical energy into a variable voltage and frequency suitable for the motor, enabling precise speed and torque control throughout all machining phases. On a CNC machining centre its failure stops the spindle or the controlled axis, rendering the machine completely unusable; recovery requires replacing the drive and reconfiguring the regulation parameters (gains, ramps, current limits) to restore the machine’s original performance.

Control Techniques, founded in 1968 in Wales (UK), is one of the world’s leading manufacturers of variable speed drives for AC and DC motors; the Unidrive range has become a benchmark in global manufacturing industry. Acquired by Emerson Electric and subsequently by Nidec Corporation in 2017, products are now marketed under the Nidec | Control Techniques brand. The Unidrive SP series has been superseded by the Unidrive M series and is considered legacy / discontinued: available primarily as used, surplus or through specialist repair.

Main Technical Specifications