Product Description:

The VT-VRPA1-50-12 plug-in amplifier is produced by Bosch Rexroth Indramat for the VT-VRPA Electric Amplifiers series. Intended for proportional valve control in industrial automation, the card translates low-level command voltages into regulated solenoid currents so hydraulic actuators follow electronic setpoints with repeatable accuracy. It mounts in a 32-way rack slot and forms part of closed-loop pressure or flow systems where a consistent current supply to a valve coil is needed during steady-state machine cycles.

Its power stage operates from a nominal supply of 24 VDC, and the circuitry draws up to 37 W under maximum load. Internal reference lines provide a symmetrical ±15 V supply for position or pressure transducers. Command shaping is smoothed by a 4700 µF, 63 VDC capacitor that reduces incoming ripple. Field wiring is routed through a DIN 41612-F32 connector, providing standardized pin assignments for the supply, setpoint, and valve leads. The setpoint channel accepts ±10 V signals and has an input resistance of 100 kΩ, so the connected control electronics are not appreciably loaded. A dedicated ±10 V potentiometer output can supply 10 mA to external trim networks, and a 10 kΩ signal-source potentiometer is recommended for stable adjustment.

The current regulator supplies a continuous coil current of 1.5 A and can rise momentarily to 2.7 A when energizing the valve. Drive logic is enabled only when the incoming line exceeds 8.5 VDC, preventing unstable operation during low-voltage starts. Coil dissipation is limited to 40 VA, helping protect the winding from excessive heat during sustained modulation. A front-panel potentiometer provides ±5% zero adjustment, allowing offset correction without external tools. The card weighs 0.25 kg and occupies little rack space, making it suitable for control cabinets where several amplifier cards must be installed together.