PSM125ES Reliance AutoMax DC Bus Supply Module

The Baldor / Reliance AutoMax SA500 Series AC Power Modules provide AC power to, and control of, brushless motors and squirrel-cage induction motors from 1-15HP. Each Power Module contains the Power Module Interface (PMI) Regulator printed circuit board and the inverter used to convert DC power to AC power for the motor. Depending upon their power requirements, up to six Power Modules can be daisy-chained together and operated from one SA500 DC Bus Supply, which provides the Power Modules a nominal 325 VDC input power.

The SA500 is a member of the AutoMax Distributed Power System (DPS) family of drives. DPS is a programmable microprocessor-based control system that is capable of real-time control of AC and DC drives. Each Universal Drive Controller (UDC) in the AutoMax rack allows the AutoMax Processor to control up to two drives (20 maximum from one rack). The UDC module communicates over a fiber-optic link with the PMI located in the SA500 Power Module. The Power Module can be located up to 750 meters (2500 feet) from the AutoMax rack.

An SA500 drive consists of a DC Bus Supply and a Power Module which supplies three-phase AC power to an induction motor or a permanent magnet brushless motor. The SA500 DC Bus Supply rectifies three-phase 230 VAC power to provide a constant DC voltage for the Power Module. A three-phase bridge consisting of three SCRs and three diodes controls the currents during charging of the DC bus capacitor. During charging, the phase angle of the SCR firing is shifted as a function of time to control the charging current. The SA500 Power Module consists of the PMI Regulator (commonly referred to as the PMI) and power circuitry to invert the DC bus voltage to three-phase 230 VAC for the motor. The power bridge consists of six bipolar transistors (three dual-transistor modules).