VT-VRPA 1-527-1X/V0/QV

The VT-VRPA 1-527-1X/V0/QV is an electric amplifier card produced by Bosch Rexroth Indramat within the VT-VRPA Electric Amplifiers series. Designed for closed-loop control of proportional pressure and throttle valves such as the 4WRP6EA and 3FREZ models, the board translates low-level command signals into a pulse-modulated drive current for connected solenoids. By inserting this card into a standardized 19-inch rack, machine builders obtain electronic regulation of hydraulic actuators without adding discrete power stages. Its integrated feedback channel monitors spool position so flow or pressure follows the external setpoint accurately.

Input power is stabilized from a nominal supply of 24 V DC, and the module draws up to 35 W while operating; this ceiling corresponds to a maximum current consumption of 1.5 A on the back-plane. The solenoid channel can deliver a peak winding current of 2.7 A or a continuous load of 25 W, values sized to the dynamic range of the proportional valve. Actual-value feedback is generated as 10.2 Veff at 7.8 kHz, while the error amplifier can source 100 mA for remote diagnostics. A 1 kΩ command potentiometer establishes the reference, and a dedicated +10 V DC rail powers that sensor. Pulse-width modulation at the solenoid output maintains force linearity across a position cable length of 50 m assuming 100 pF per meter.

The card occupies a 100 × 160 mm Euroboard footprint and slides behind a front plate that is 7 TE wide, so it fits alongside other Rexroth modules without blocking airflow. Electrical interfacing is handled through a DIN 41612-F32 connector that routes power, feedback, and solenoid lines toward the manifold. Despite the integrated power electronics, the assembly weighs only 0.37 kg, which eases rack installation and limits inertial loading on light enclosures.