Lenze TT140 Modules

Technical Dossier

Product Details And Specifications

Lenze TT140 Series Technical Notes

The Lenze TT140 is a DC drive control module within the Lenze modular drive system architecture, deployed extensively across global heavy industry sectors including chemical processing plants, oil refineries, nuclear auxiliary systems, paper mills, and steel rolling lines. The TT140 series functions as a thyristor-based DC drive controller, providing precise armature current regulation and field control for DC motors in the range of several kilowatts to several hundred kilowatts. Its modular backplane design allows integration into Lenze's broader automation cabinet infrastructure, making it a long-standing reference component in retrofit and greenfield industrial installations across Europe, Asia, and the Americas.

The TT140 platform is recognized for its robust analog and digital I/O interface, its compatibility with Lenze's proprietary bus systems, and its field-proven reliability in continuous-duty industrial environments. Installed base units remain operational in facilities where replacement with modern digital drives is not economically or operationally feasible, creating sustained demand for spare parts, repair services, and lifecycle extension support.

The Evolution of TT140 Architecture

The TT140 series was developed as part of Lenze's DC drive product line during the industrial automation expansion of the 1980s and 1990s. Early variants used analog control boards with discrete component regulation circuits. Mid-generation revisions introduced digital setpoint interfaces and improved EMC shielding to comply with evolving European CE directives. Later production runs incorporated optocoupler-isolated gate firing circuits and enhanced diagnostic LED arrays for field fault identification.

The TT140 architecture is based on a 6-pulse thyristor bridge topology for armature control, with a separate half-wave or full-wave thyristor stage for field weakening. Control boards communicate via Lenze's internal parallel bus, and the module slots into a standardized 19-inch rack or dedicated Lenze cabinet frame. Compatibility with older Lenze 3000 series and 4000 series cabinet systems is a key operational constraint when sourcing replacement units — board revision levels and firmware versions must be matched to the host system's backplane revision.

TT140 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified models within the Lenze TT140 DC drive module family, classified by functional role:

DC Armature Control Boards

TT140: Core DC drive thyristor control board, 6-pulse armature regulation, analog setpoint input.
TT140A: Variant A — enhanced current limit circuit, improved thermal protection relay interface.
TT140B: Variant B — extended speed range, modified field weakening threshold parameters.
TT140C: Variant C — dual-channel feedback input, used in tension-controlled winder applications.
TT140D: Variant D — digital speed reference input, 0–10V and 4–20mA selectable via DIP switch.

Field Control Modules

TT140-F: Dedicated field current regulator board, half-wave thyristor output, compatible with TT140 armature boards.
TT140-FW: Full-wave field controller variant, higher field current capacity for large frame DC motors.
TT140-FE: Field economy module — reduces field current during motor standstill to minimize thermal losses.

I/O and Interface Boards

TT140-IO1: Analog I/O expansion board, 4 analog inputs, 2 analog outputs, DIN rail mountable.
TT140-IO2: Digital I/O expansion, 16 DI / 8 DO, 24VDC logic, used for sequence interlock wiring.
TT140-RS: RS-232/RS-485 serial interface adapter for parameter upload/download and remote monitoring.
TT140-PB: PROFIBUS-DP communication adapter, allows TT140 integration into Siemens S7 and other PROFIBUS master systems.

Power Supply and Auxiliary Boards

TT140-PS: Internal 24VDC auxiliary power supply board for control electronics, replaces failed onboard SMPS.
TT140-PSR: Redundant power supply module for high-availability cabinet configurations.
TT140-GD: Gate driver board, thyristor firing pulse amplifier, direct replacement for failed firing circuits.

Feedback and Encoder Interface

TT140-ENC: Incremental encoder interface board, HTL/TTL selectable, up to 10,000 PPR, used for closed-loop speed control.
TT140-TAC: DC tachogenerator input board, 10–200V tach input range, replaces encoder feedback in legacy motor configurations.

Quality Control for the TT140 Range

The TT140 module presents specific quality control challenges due to its thyristor-based power stage and analog control circuitry. DriveKNMS applies the following test protocol to all TT140 units prior to dispatch:

Each board undergoes visual inspection for capacitor bulge, PCB trace corrosion, burnt resistors, and cracked solder joints — failure modes common in boards with 15–30 years of service. Thyristor gate-cathode resistance is measured on all six devices of the armature bridge. Gate firing pulse timing is verified using an oscilloscope against Lenze's published firing angle specifications. Analog setpoint input linearity is tested across the full 0–10V range with a calibrated signal source. Field current output is loaded and measured at 25%, 50%, 75%, and 100% of rated field current. Communication interface boards (RS, PB variants) are tested for data integrity using loopback and live PLC connection tests. All units are burned in under load for a minimum of 4 hours before final inspection sign-off.