Product Core Brief

• Model: LDMTR-01
• Part number: 63940135F
• Brand: ABB
• Series: ABB drive / motion control feedback interface family
• Core Function: Provides analog motor speed feedback—typically from a DC tachometer or speed generator—to ABB drive or motion control systems.
• Product Type: Tachometer / speed feedback interface module (not a PLC CPU, not a general-purpose I/O module, not a standalone power supply)
• Key Specs: Part no. 63940135F | Board marking LDMTR-01 | Legacy/obsolete spare
• Condition: New Original / New Surplus / Refurbished (subject to stock)

Key Technical Specifications

• Part number: 63940135F
• Board marking:
• Product type: Motor speed feedback / tachometer interface module
• Typical application: ABB DC/AC drive systems; closed-loop speed control
• Feedback type: Analog tachometer / DC speed generator interface
• Typical input: Tachometer voltage proportional to motor speed
• Typical output to controller: Scaled analog speed feedback signal
• Supply voltage: Confirm against original cabinet documentation; many ABB feedback modules use 24 V DC or drive-derived supply
• Installation: Slot-mounted in ABB drive or control cabinet
• Obsolescence status: Obsolete; supplied through surplus/refurbished channels
• Handling: ESD-sensitive; anti-static packaging required
• Documentation: Electrical ratings and pinout must be verified against the original OEM manual

 

Product Introduction (No Fluff)

The ABB LDMTR-01 (63940135F) is a legacy speed feedback module used to interface motor tachometer signals into ABB drive or motion control systems. It converts analog tachometer voltage into a usable speed feedback signal for closed-loop regulation.

Because this is an obsolete board, replacement accuracy is critical. Always match both the board marking LDMTR-01 and part number 63940135F against the original cabinet BOM before installation.

 

QA & Testing SOP (Dynamic & Transparent)

Speed feedback modules sit between the motor and the control loop, so testing focuses on identity, signal integrity, and safe validation.

1. Identity verification: Confirm LDMTR-01 board marking and 63940135F part number. Check connector layout, silkscreen, and LED indicators against reference photos.
2. Visual inspection: Inspect for burnt components, cracked solder joints, swollen capacitors, corroded terminals, and damaged backplane contacts. Tachometer circuits can be exposed to noise and voltage transients.
3. ESD-safe handling: Store and ship in anti-static bags. Do not handle the module near live drive terminals.
4. Bench power-up test: If a compatible test setup is available, verify basic power-up behavior, LED status, and analog output stability. Do not apply full drive voltage during bench testing.
5. Signal-path check: Verify tachometer input wiring, polarity, shielding, and output scaling before returning the module to service.

 

Installation Pitfalls & Guide (Engineer to Engineer)

❗ Do not substitute by partial model number. LDMTR-01 and 63940135F must both match the original BOM. Other ABB feedback or I/O modules are not automatically compatible.

❗ Confirm the tachometer type first. This module is intended for analog speed feedback. Connecting an incompatible encoder or tachometer can produce incorrect speed readings or drive faults.

❗ Check cable shielding and grounding. Poor shielding on tachometer cables is a common source of noise, speed ripple, and false trips.

❗ Avoid hot insertion unless the OEM manual explicitly allows it. Drive feedback circuits can behave unpredictably if swapped under power.

Replacement steps:

1. Pre-install: Lock out/tag out drive power, photograph tachometer wiring, and prepare ESD protection.
2. Removal: Label all connectors, remove the module straight out, and inspect the slot/backplane contacts.
3. Install: Seat the replacement module firmly, reconnect wiring exactly as labeled, and verify mechanical retention.
4. Commissioning: Restore auxiliary power first, check LEDs/fault codes, verify speed feedback stability, then perform supervised run-up tests with protection enabled.

 

Technical FAQ

1. Is the LDMTR-01 63940135F still available new from ABB?
It is generally treated as an obsolete/legacy module. Most supply now comes from new surplus, unused old stock, or refurbished inventory.

2. Can I use another ABB feedback module instead?
Not without confirmation. Feedback modules differ in signal type, voltage range, pinout, and drive compatibility. Always verify against the original cabinet BOM and OEM documentation.

3. What warranty should I expect?
Twelve months is typical for surplus/aftermarket industrial modules. Exact terms depend on condition and supplier policy.

4. Is this module the same as a general-purpose I/O card?
No. It is designed for motor speed feedback, not generic digital/analog I/O tasks. Using it outside its intended role risks configuration and pinout mismatches.

5. What should I check before commissioning a replacement?
Confirm the cabinet model, module position, part number, tachometer wiring, shielding, drive parameters, and speed feedback scaling. For drive systems, never commission blind—incorrect speed feedback can cause instability, over-speed faults, or mechanical damage.