Product Description:

Pacific Scientific manufactures the SC726A-001-PM2009 in its SC720 Command Controllers series. The unit belongs to the servo controller product group and is intended to close torque and velocity loops for permanent-magnet servomotors in assembly machines, material-handling cells, and similar automated stations. By rectifying three-phase mains power, regulating the internal DC bus, and modulating output through high-frequency switching, it provides precise axis command and protects connected motors during dynamic load changes.

The controller draws bus power from a 240 VAC, 47–63 Hz, three-phase supply and maintains the control electronics with a separate 90–264 VAC, single-phase input, which helps isolate logic from motor power for noise immunity. Inside the unit, a 320 Vdc link is generated to serve the output bridge that can sustain 60 A continuously and deliver up to 120 A during acceleration events. Pulse-width modulation at 20 kHz minimizes current ripple so the downstream motor sees nearly sinusoidal excitation. The built-in torque and velocity control architecture accepts resolver feedback and closes the current loop fast enough to maintain commanded motion profiles.

When paired with a Pacific Scientific 720-series motor, the power stage can supply 18 kW of mechanical power during continuous three-phase operation and reach 36 kW for brief surge demands. Excess energy from overhauling loads is routed to an onboard shunt regulator that dissipates 500 W continuously or clips regenerated peaks as high as 40 kW. At the application level, the drive targets a system rated speed of 4000 rpm, delivering 120 lb-in of steady torque and up to 410 lb-in at stall while maintaining positioning accuracy of ±22 arcmin. A 1024-ppr encoder emulator, backed by 12-bit resolver-to-digital conversion, provides fine velocity feedback to the host controller.