Initial situation and fault description.

A machine manufacturer sent us four identical Omron R7M-A20030-BS1-D AC servo motors for overhaul at the same time. According to the initial description, all motors showed the same behavior: they were no longer detected by the control system and could not be commissioned. In practice, this fault pattern usually appears as an immediate alarm at servo power-on or as a failed initialization before the axis can be enabled.

After connecting the motors to our test setup, the suspicion was quickly confirmed. In all four cases, the encoder could no longer be initialized. No feedback was available and the drive system classified the motor as faulty or not present. This kind of repetition rarely happens by coincidence and almost always points to a common root cause.

Root cause analysis from workshop experience

The encoder is one of the most sensitive components of a servo motor. It operates with delicate electronics, low voltages and tight tolerances. The Omron R7M-A20030-BS1-D is equipped with an incremental encoder, which is reliable in many applications but highly sensitive to environmental influences.

During disassembly of all four motors, a familiar picture appeared: moisture ingress into the encoder compartment. Even condensed air, coolant mist or fine emulsions can enter the encoder area via seals or connectors. Once moisture reaches the electronics, corrosion, leakage currents or short circuits occur. The result is almost always the same: the encoder can no longer be initialized and fails completely.

Repair and overhaul process

All four motors were completely disassembled and inspected according to our standardized procedure. The defective encoder was replaced with a TRD-FY2000 encoder from Yaskawa. This encoder has proven itself in comparable applications and provides stable, clean feedback when operated with SmartStep systems.

At the same time, the integrated KS-50B-055 holding brake was inspected. Especially with motors equipped with brakes, this step is essential, as moisture can affect not only the encoder but also the brake mechanics and coil. In this case, the brakes were electrically and mechanically intact, but they were cleaned and checked to ensure reliable holding torque at standstill.

In addition, all motors received new bearings and seals. This preventive measure makes sense during an encoder overhaul, as the motor is already fully disassembled and potential secondary damage can be avoided. After reassembly, each motor underwent a complete electrical inspection and an extended test run on the servo amplifier, including homing and monitoring of the feedback signals.

Test result and conclusion

After the overhaul, all four Omron R7M-A20030-BS1-D motors were detected correctly and initialized without any issues. Encoder signals were stable, motor operation was smooth and repeatable, and the brakes functioned reliably. For the customer, this meant full machine availability without the need for costly replacement with new motors.

This case clearly demonstrates how critical the protection of the encoder area is. The encoder is not a classic wear part, but it reacts extremely sensitively to environmental influences. Regular visual inspections of connectors and seals can significantly reduce the risk of expensive downtime.

Weitere Informationen wie Preis, Lieferzeit zu erwähnten Geräten:

• Omron R7M-A20030-BS1-D Servomotor
• Encoder Yaskawa TRD-FY2000
• Bremse Kyowa KS-50B-055
• Omron SmartStep Drive R7D-AP02H

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Omron R7M-A20030-BS1-D

Overview

The Omron R7M-A20030-BS1-D is a brushless AC servo motor from the SmartStep series. The SmartStep systems combine motor, encoder and servo amplifier into a compact, robust drive solution for precise positioning tasks in industrial automation.

Model designation

200 = 200 W
30 = 3000 rpm
B = with integrated brake
S1 = standard shaft
D = IP67 connectors

Motor technical specifications

Encoder and brake

Compatible servo amplifier

SmartStep servo amplifier R7D-AP02H

Note: The -D variant uses IP67 connectors. Standard flying lead cables are not compatible.

Alarm messages Omron SmartStep servo amplifier R7D series

Most relevant for this repair case:
AL.04 and AL.05 occur very frequently when moisture enters the encoder compartment and cause the motor to no longer be recognized by the system.

Typical applications

• Packaging machinery
• Assembly systems
• Pick-and-place units
• Handling axes
• Special-purpose machinery
• Retrofit from stepper motor axes to servo technology

Service and maintenance recommendations

• Regular inspection of encoder connectors
• Protection against coolant mist and condensation
• Preventive replacement of seals during service
• Electrical and mechanical brake inspection
• Visual inspection of the encoder compartment during every overhaul