A new range of drives for slip ring motors has recently been introduced by Sprint Electric. A slip ring motor is a type of induction motor having a wound rotor connected to slip rings. Typical applications for slip ring motors include cranes, where the motors are used to control the hoist as well as the X/Y movement.

Sprint Electric’s JL/X range of slip ring motor drives is a derivation of the PL/X digital DC drive product range. It shares the same software and hardware platforms and delivers the same digital control functionality. The main difference is that the thyristor stack configuration has been designed to provide a 3-phase output (U, V, W) suitable for controlling slip ring motors in either 2- or 4-quadrant modes. All the fieldbus options including Profibus, DeviceNet, CC-Link, EtherNet/IP, Modbus and CANopen, and configuration software packages used with the PL/X are also available for the JL/X range.

The range of slip ring motors cover output currents from 100-1,850A and come in three frame sizes with standard supply voltage inputs up to 480V AC. Overload capability is 150%. For high duty applications, the JL/XHD range is available with an overload capability of 250%. There is also the option of high voltage units that are able to accept AC supply voltages up to 690V AC for higher voltage applications. All models have the high current 3-phase supply terminals in standard top entry, with the motor connections being bottom entry. The JL/X is supplied configured for crane control as standard, with joystick or analogue demand inputs and outputs needed to control up to four external slip ring resistors, together with dedicated outputs for super synchronous regenerative lowering and brake control.