Product Description:

The PC843-XYZ-A is a brushless servo drive produced by Pacific Scientific and belongs to the PC800 – PCE800 Brushless Servo Drives series. Designed for closed-loop velocity and position control of permanent-magnet servomotors in automated machinery, the unit converts three-phase mains power into regulated outputs for precision motion. Within an automation cell, the drive connects to a SERCOS fiber network, allowing deterministic exchange of setpoints and feedback with a central motion controller. Its closed-loop architecture supports repeatable coordination of speed, torque, and position across connected axes.

During continuous operation, the converter section delivers 3.6 A RMS while sustaining 1.5 kW of three-phase power, which sets the thermal load on cabinet airflow systems. For rapid accelerations, it can supply a surge of 10.6 A RMS for five seconds and reach a momentary output of 4.5 kW, giving the axis extra headroom for start-stop profiles. The silicon devices inside the power stage run at 98% efficiency, so only minimal energy is lost as heat. Incoming 240 VAC is rectified, and excess bus energy is routed to an internal shunt that can dissipate 200 W continuously. Six opto-isolated inputs, three opto-isolated outputs, and a relay rated 30 VDC at 1 A provide discrete machine interfacing, while a 24-bit DRDC resolver interface closes the high-resolution feedback loop.

The SERCOS command channel can be clocked up to 16 MHz, minimizing cycle times between the motion controller and the drive. Internally, a current-mode velocity regulator with a 400 Hz closed-loop bandwidth tracks reference changes without overshoot and supports stable speed control during rapid load changes. When regenerative braking events exceed the continuous shunt limit, the hardware can absorb 30 J per event and divert peaks of 12.8 kW to the resistor bank for one second, preventing DC bus overvoltage trips. This arrangement helps the drive remain stable during load reversals, pallet drops, and sharp tooling deceleration.