VT-VRPA1-527-10/V0

The VT-VRPA1-527-10/V0 is an electric amplifier card produced by Bosch Rexroth Indramat for the VT-VRPA Electric Amplifiers series. Designed for panel installation inside hydraulic control cabinets, the unit conditions low-level command signals so they can drive proportional pilot valves in industrial automation systems. By adjusting coil current in proportion to a voltage or potentiometer setpoint, the amplifier enables precise modulation of flow or pressure actuators attached to servo-hydraulic machinery. Its circuitry integrates directly with Rexroth pilot stages for straightforward installation in existing manifolds.

Electrical connections are made through a DIN 41612-F32 backplane connector that mates with Eurocard racks and carries all supply and signal lines. The logic and power sections operate from a 24 V DC bus, and the card draws approximately 37 W at this voltage. Circuit protection has a continuous current rating of 1.5 A. Analog setpoints encounter an input resistance of 100 kΩ, minimizing the load on PLC outputs, while the pilot feedback path has a resistance of 20 kΩ. A bulk capacitor rated at 4700 µF / 63 V DC smooths voltage ripple so the solenoid current remains steady. The 10 kΩ signal potentiometer and 10 mA reference supply support local gain or zero adjustments. This arrangement allows the card to process low-level control signals while maintaining stable current delivery to the connected hydraulic valve.

The output stage is designed for pilot valves of size NG 6. It can source a peak coil current of 2.7 A and support an electromagnetic load of up to 40 VA without overheating. A fault terminal supplies 100 mA to operate an alarm lamp or PLC input when the amplifier detects undervoltage or overcurrent. The alarm connection allows the control system to respond to an electrical fault without interrupting the analog command path. Stable current regulation helps the proportional spool follow changes in the incoming setpoint during flow or pressure control. The card’s panel-mounted format also keeps signal, supply, feedback, and fault connections within the same backplane assembly.