• Parker Hannifin Corporation

Emc-Compliant Brushless Servo Motor

Parker Hannifin Corporation, Compumotor Division, has introduced a new CE-marked brushless servo that features a built-in interface for step-and-direction input signals from standard step motor controllers or PLCS. The new BDS-E provides a simple means of implementing systems that contain a mix of stepper and servo technologies, using just one controller. The servo also offers system integrators a particularly cost-effective way of upgrading existing automation systems, allowing step motors to be replaced with high performance servos without incurring the expense of complex servo controllers. The BDS-E package is available with different combinations of drives and motors, and is capable of accommodating speeds up to 5,000 RPM and peak torques to 124 in-lbs. A major feature of the new system is direct on-line operation at 230 V AC without the additional size, weight and cost of a separate transformer. The BDS-E fully complies with the European EMC and Low Voltage Directives, and requires no additional transformers, power supplies or external filter units. Each BDS-E Series servo system comprises a high performance drive and 3-phase brushless motor, and employs highresolution sinusoidal commutation to ensure extremely smooth rotation over the full speed range. Two drive units are available, with continuous current outputs of 3 A (Model BDS75E) and If (Model BDS150E), and two motors, making it easy for users to select the optimum package for their requirements. The system's 6-pole MD Series servo motors employ rare earth magnets to create the high air-gap flux densities needed to maximise torque and efficiency, and are designed and manufactured by Parker's European Electromechanical Division. Each motor features alternative shaft diameters with improved dimensional tolerances to aid the fitting of components such as precision gearboxes, and incorporates a built-in 1,024-line incremental encoder to generate commutation data and provide position feedback. All drive configurations are performed using bit switches located on the front panel. The drive's stepand-direction inputs are optically isolated, and accept standard differential TM-level control signals from a step motor controller or PLC. The step pulses are fully buffered within the drive, enabling pulses of varying duration and repetition frequency to be easily accommodated; this is particularly useful when using low-cost PLCs to control a highly dynamic application such as a flying knife or shear, allowing bursts of pulses to be interpreted as accurate acceleration/deceleration ramps. The BDS-E can handle step pulse rates of up to 350 kHz, commanding a speed of 5,000 RPM when the drive is set to its maximum resolution of 4,096 steps/rev.