EMP-A-20 by Vickers

The EMP-A-20 amplifier board is produced by Vickers and belongs to the Vickers Amplifier Boards series. Designed for machine control racks, the board converts field supply power into conditioned DC rails and provides signal amplification for proportional solenoid or servo valve electronics used throughout automated hydraulic systems. By integrating regulated main and auxiliary outputs on one card, it simplifies cabinet wiring and delivers the stable voltages required for repeatable valve positioning cycles in presses, molding machines, and other closed-loop industrial processes.

The board is factory wired for a single-phase input of 115 V AC, yet jumpers allow operation from an alternate mains level of 230 V AC; both ranges accept line frequencies of 50 or 60 Hz. Internal conversion produces an unloaded main rail of 20 V DC that can deliver up to 2.5 A DC to connected valve coils. Under worst-case demand, peak ripple is limited to 0.6 V RMS, while line regulation holds variation to 12% with a 10% change in supply and load regulation remains within 12% between 0 and 2.5 A. A secondary supply of 12 V DC supports control electronics, and the auxiliary rail shows only 0.05 V of line shift for a 10% mains swing and 0.03 V of droop between 0 and 40 mA.

A steady auxiliary current of 200 mA is available per leg for sensors or reference circuits. Overcurrent protection is provided by a 1 A time-delay fuse that helps prevent nuisance trips during inrush. The module is specified for ambient temperatures up to 65 °C, allowing placement in hydraulic power units where elevated oil and enclosure heat are common. Mechanical installation is simplified by a card weight of 4.1 kg (9 lb), which is light enough for slide-in sub-rack frames and substantial enough to act as a thermal sink for the onboard regulators.