Product Description:

The SPM 17-TD inverter module is a power electronic unit manufactured by Bosch Rexroth Indramat for the SPM Inverter Modules series. It mounts inside Rexroth multi-axis drive racks and converts the shared DC-bus energy into controlled spindle or servo power. Within an automation cell, the module serves as a bridge between the central supply unit and the motor axes, enabling speed regulation, current limiting, and coordinated braking functions for machining, packaging, or handling equipment. Its rack-based layout keeps power distribution and axis control functions centralized inside the drive system. This arrangement is common in machine tools and automated production equipment that use a shared power supply for multiple motion channels.

Mechanical and thermal safeguards begin with the combo screw on the DC link, which must be tightened to 3.7 Nm so the connection remains low in resistance during vibration. For system interconnection, an intermodule ribbon connects to port X8, passing firing commands and fault data to adjacent inverters. Individual motor feedback is routed through port X5, which accepts TTL or sinusoidal encoder signals so the controller can close its velocity loop. The I²t monitoring function uses the threshold of <5 Hz. Below that frequency, the processor accumulates energy rather than relying only on peak current to judge overload. If that limit is exceeded, the Btb1 relay shifts to the protective state designated as Open, isolating the output stage.

Axis-specific signals continue on the spindle encoder connector X55, allowing high-resolution position data to travel directly to the motion CPU without external breakout boards. High-resolution feedback from this encoder path supports accurate spindle and axis response during synchronized motion. Peripheral electronics such as fans, brake relays, or proximity sensors draw from the auxiliary supply at 24 VDC on terminal block X35, eliminating the need for a separate power pack inside the cabinet. The Btb2 relay opens on instantaneous overcurrent to clear the bus before semiconductors are damaged.