VT-VRPA1-52-1X/

The VT-VRPA1-52-1X/ is a plug-in electric amplifier manufactured by Bosch Rexroth Indramat for proportional valve control within automated hydraulic systems. Belonging to the VT-VRPA Electric Amplifiers series, the card occupies a standardized 32 mm section of a Euro-style rack and converts low-level setpoint voltages from a PLC into controlled current for a solenoid coil. This operation allows precise regulation of spool position and fluid flow without mechanical feedback devices, making the amplifier an interface between electronic motion commands and hydraulic actuation.

The amplifier is supplied by a stable 24 V DC source, and its total power draw is limited to 37 W, so cabinet heat generation remains moderate. An onboard converter generates a symmetrical reference of ±15 V for external position transducers, while the command channel accepts a differential setpoint of ±10 V. At full output, the power stage can deliver up to 1.5 A of continuous current, matching the requirements of compatible Rexroth proportional solenoids. The operator can trim the offset through a zero-adjustment range of ±5%. The main gain element is a 10 kΩ potentiometer supplied with 10 mA. Input impedance toward the control system remains high at 100 kΩ, minimizing signal-loading errors. A seven-slot front panel provides space for test jacks and adjustment trimmers.

For system diagnostics, the card features a fault relay that handles up to 100 mA when an overcurrent or supply error is detected. It follows the European format, allowing direct insertion into DIN 41494 subracks alongside other VT modules. The power stage supports a proportional valve solenoid load of 2.7 A / 40 VA. Ripple is damped by a 4700 µF/63 V DC smoothing capacitor, which helps prevent oscillation during rapid command changes.