VT-SSPA1-5-1X/V0/0-24

The VT-SSPA1-5-1X/V0/0-24 is a plug-in proportional amplifier built by Bosch Rexroth Indramat for the VT-SSPA Plugin Proportional Amplifiers series. It occupies a card slot inside a control rack and supplies regulated current to a single solenoid coil, allowing hydraulic directional or pressure valves to follow an analog command signal. The closed-loop current control allows a machine controller to adjust actuator force or flow through electrical commands rather than mechanical adjustments.

This amplifier operates from a supply of 24 VDC and can deliver a nominal coil current of 1.2 A. The internal oscillator runs at 200 Hz, creating a chopper waveform that helps maintain linear magnetic force while limiting coil heating. A command input resistance of 20 kΩ prevents excessive loading of the upstream PLC output. The bias current is set to 0 mA, so the solenoid is fully de-energized when no reference signal is present. The housing has an IP65 rating, protecting the electronics against dust and low-pressure water jets. Position feedback is not included, so the amplifier regulates coil current while the valve spool operates without a closed position loop.

Field wiring enters through a PG11 cable gland and terminates on four screw terminals. The power stage connects to the valve through an EN 175301-803 interface with two power pins and a protective earth connection. The output stage supports coils with a minimum inductance of 15 mH, helping control current ripple during the pulse-width modulation cycle. The connected harness can have up to 100 µH of distributed inductance without destabilizing the driver. For temperature-rise calculations, the coil resistance is 4.77 Ω. An M3 × 40 mm screw set secures the assembly in place and provides stable mechanical retention during machine operation.