Product Description:

The VM350 is a power amplifier module from Bosch Rexroth Indramat that belongs to the VM Amplifier Drives series. In an automation cabinet, it acts as the interface between a three-phase mains supply and the control electronics, generating regulated DC rails and drive signals that feed connected servo axes. Its role is to manage energy flow, monitor feedback, and support stable motor operation during coordinated motion sequences.

The unit’s housing measures 53 × 271 × 285 mm, so it occupies a single narrow slot on a backplane and weighs only 2.8 kg, which helps keep cabinet layouts compact. An enclosure rating of IP20 provides basic finger protection, so the module must be mounted inside a closed cabinet. Internally, the DC link can rise to 420 V DC, and this voltage is produced from the three-phase input for the individual logic rails. The amplifier furnishes 5.1 V Vcc at 7 A, -24 V Vdd at 0.8 A, and 24 V Vee at 10 A to supply encoders, interface boards, and gate drivers. Under continuous loading at 230 V three-phase, the module delivers a nominal apparent power of 3000 VA. Connection screws on the XDN2 terminal must be tightened to 0.3 Nm to maintain reliable contact without damaging the conductor strands.

For dynamic events such as rapid acceleration or regenerative braking, the VM350 can sustain 10000 VA for 5 seconds, giving the drives additional short-term power capacity. Control circuitry is fed by an external supply of 24 V at 1 A, allowing the logic to remain active during mains interruptions. The design permits installation up to 2000 m above sea level without derating. Above that altitude, lower air density reduces cooling effectiveness. When fitting the module, the 230 V mains must be fused for the indicated currents, and the cabinet layout must allow convection across the vertically oriented heat sink so the internal rails remain within their rated currents.