Bosch Rexroth TDM1.2 AC Servo Drive Modules

Technical Dossier

Product Details And Specifications

Bosch Rexroth TDM1.2 Series: Comprehensive Module Range and Technical Overview

The Bosch Rexroth (Indramat) TDM1.2 series represents one of the most widely deployed AC servo drive platforms in global heavy industry. Installed across chemical processing plants, nuclear power facilities, oil refineries, steel mills, and automotive body-in-white lines, the TDM1.2 drive family operates as the power conversion and axis control backbone within Indramat DIAX02, DIAX03, and DIAX04 drive systems. Its modular architecture—combining a compact power section with an integrated digital control board—made it the standard axis drive for multi-axis CNC and motion control applications throughout the 1990s and into the 2000s. Units in this series remain in active service at facilities where full system replacement is cost-prohibitive, making verified spare parts availability a critical operational requirement.

The Evolution of TDM1.2 Architecture

The TDM (Transistor Drive Module) designation identifies the drive's transistor-based IGBT output stage, distinguishing it from earlier thyristor-based predecessors. The TDM1.2 generation succeeded the TDM1.1 platform, introducing improved digital signal processing, enhanced fault diagnostics via the H1/H2 display, and expanded compatibility with Indramat MDD, MKD, and MHD servo motor families through standardized resolver and encoder feedback interfaces.

The TDM1.2 communicates with the system controller via the SERCOS fiber-optic ring bus (standard) or analog ±10V command interface, depending on the installed control card variant (DSS, DST, or DKS). Firmware is stored on an exchangeable module (MOD), allowing field reconfiguration without hardware replacement. The drive accepts 3-phase AC mains input (typically 200–480 VAC depending on variant) and delivers a regulated DC bus to the connected motor. Cooling is achieved via an integrated fan and internal heat sink; the drive is designed for cabinet mounting in IP54-rated enclosures.

As the TDM1.2 series has entered its end-of-life phase under Bosch Rexroth's product lifecycle policy, the recommended migration path is to the IndraDrive C (HCS) or IndraDrive M (HMS/HMD) platform. However, direct electrical and mechanical substitution requires significant re-engineering of the control cabinet, motor cabling, and PLC interface. For facilities operating legacy Indramat systems, maintaining a verified stock of TDM1.2 spare drives is the lowest-risk continuity strategy.

TDM1.2 Full Catalog & Functionalities (SKU List)

The following SKUs represent the primary current and peak current ratings available within the TDM1.2 product family. Ratings are expressed as continuous current (A) / peak current (A). All units are single-axis AC servo drives unless otherwise noted.

TDM1.2-04-300-W1: 4A continuous / 300V DC bus, low-power axis drive for light-duty servo axes.
TDM1.2-06-300-W1: 6A continuous / 300V DC bus, standard small-axis drive for positioning applications.
TDM1.2-08-300-W1: 8A continuous / 300V DC bus, compact drive for MDD servo motor pairing.
TDM1.2-12-300-W1: 12A continuous / 300V DC bus, mid-range axis drive for MKD motor series.
TDM1.2-20-300-W1: 20A continuous / 300V DC bus, standard drive for medium-torque servo axes.
TDM1.2-30-300-W1: 30A continuous / 300V DC bus, high-current drive for heavy-duty CNC axes.
TDM1.2-50-300-W1: 50A continuous / 300V DC bus, high-power axis drive for large MHD servo motors; this listing.
TDM1.2-100-300-W1: 100A continuous / 300V DC bus, maximum-current variant for high-inertia load axes.
TDM1.2-04-300-W0: 4A / 300V, W0 control card variant with analog command interface.
TDM1.2-06-300-W0: 6A / 300V, W0 analog interface variant for legacy CNC integration.
TDM1.2-12-300-W0: 12A / 300V, W0 analog interface, compatible with non-SERCOS controllers.
TDM1.2-20-300-W0: 20A / 300V, W0 analog interface for retrofit and legacy system support.
TDM1.2-30-300-W0: 30A / 300V, W0 analog interface, high-current legacy axis drive.
TDM1.2-50-300-W0: 50A / 300V, W0 analog interface, high-power legacy axis drive.
TDM1.2-100-300-W0: 100A / 300V, W0 analog interface, maximum-current legacy variant.
TDM1.2-20-300-W1-220: 20A / 300V, W1 SERCOS, 220V mains input variant for specific regional installations.

Sourcing Hard-to-Find & Obsolete TDM1.2 Parts

Bosch Rexroth formally discontinued active production of the TDM1.2 series. Standard distribution channels no longer carry new stock. DriveKNMS maintains a dedicated inventory of tested TDM1.2 units sourced from decommissioned production lines, controlled factory closures, and OEM surplus channels. Each unit is catalogued by full part number including current rating, bus voltage, and control card suffix to ensure exact-match replacement.

Quality Control for the TDM1.2 Range

Each TDM1.2 unit processed by DriveKNMS undergoes a structured test protocol specific to the drive's internal architecture. The IGBT output stage is load-tested at rated current to verify switching integrity and thermal performance. The DC bus capacitor bank is measured for capacitance and ESR to identify age-related degradation. The resolver/encoder feedback interface is verified for signal integrity across the full speed range. The SERCOS fiber-optic transceiver (W1 variants) is tested for optical power output and receive sensitivity. The H1/H2 diagnostic display and all front-panel indicators are functionally verified. The MOD firmware module is read and version-confirmed against the unit's hardware revision. Units that fail any parameter are quarantined and not offered for sale. Test records are retained and available upon request for critical applications.