Product Description:

The VT-VRPA1-100-10 is a plug-in electric amplifier manufactured by Bosch Rexroth Indramat within the VT-VRPA Electric Amplifiers series. The card mounts on a subrack and conditions command signals to drive proportional solenoid valves in hydraulic control loops. By converting low-level inputs into controlled coil current, it enables precise modulation of pressure or flow in industrial automation systems.

The amplifier operates from a supply of 24 VDC, with a functional voltage range of 22 V to 35 V. At maximum load, the board draws 1.5 A maximum, resulting in a worst-case demand of 35 W maximum from the cabinet power bus. A 32-pin blade connector compliant with DIN EN 60603-2 Form D routes power and I/O signals, while the 100 Ω current-input resistance protects upstream controllers from excessive source current. Internally, a pulse-width-modulated oscillator operating at 2.5 kHz ±10% sets the dither frequency that linearizes valve spool motion. The regulated output channel can deliver a coil current of 2.2 A ±10% into a 10 Ω solenoid, and the rail load monitor provides a feedback signal of ±25 mA. Separate enable and ramp-disable thresholds above 10 V allow external logic to control power and slope functions without mechanical relays.

Overcurrent protection is provided by a field-replaceable fuse with a 2.5 A time-delay rating, which opens before the board traces overheat. The card generates symmetric logic rails of ±9 V ±1% for its analog circuitry, keeping reference drift within tight limits across the operating temperature range. When driving coils with a resistance of 10 Ω, the amplifier achieves full stroke without exceeding its thermal limits. A higher coil resistance would proportionally reduce the available output current and valve actuation. The amplifier has a mass of 0.15 kg, minimizing stress on the edge connector during vibration. Its compact profile also leaves clearance for adjacent cards in densely populated control racks.