The milling machine would not change tools, yet no specific fault code was reported. A customer in Latvia sent us a Yaskawa Juspeed-F CIMR-22CS2 for inspection. Our workshop diagnosed a defective 100-ohm braking resistor and defective braking control circuitry. The unit received a complete preventive overhaul and was subsequently tested with a motor.

Documented device information

Symptoms reported by the customer

The milling machine did not complete a tool change, and a red light remained on. The customer described the symptoms as follows:

“no error on it. The red light is on and does not change the tool on the milling machine.”

No specific fault code or flashing pattern was reported. The precise location of the indicator mentioned by the customer is not documented.

Technical findings in our workshop

Both faults were diagnosed during inspection. The white ceramic resistors visible in the photographs are marked 5 W and 10 Ω. Their appearance does not identify them as the faulty 100-ohm braking resistor.

How the braking circuit works

During deceleration, a motor can operate as a generator and return energy to the inverter DC bus. This can raise the DC bus voltage. A resistor braking circuit dissipates this energy as heat in a braking resistor. The braking control circuitry operates the associated switching function.

A defective resistor or control circuit can impair this energy dissipation. Examining both functions together is therefore technically relevant. Resistance alone does not establish permissible braking power: resistor power rating, duty cycle and control circuit design also matter.

The exact relationship between the braking circuit and the tool-change interlocks on this machine cannot be established without its wiring diagram and sequence diagnosis.

Preventive overhaul and motor test

Following diagnosis, the unit received a complete preventive overhaul and was then tested with a motor. This workshop test took place outside the customer’s machine. It does not document a test of the complete tool-change sequence on the milling machine.

The photographs show the unit before repair and additional device views. The video footage supplements the documentation with views of the device and its wired test setup.

Red POWER LED and fault indication

The photographed board has a red LED labelled POWER. A steady red light alone does not identify a particular fault. Indicator location, labelling and any flashing pattern must be considered when interpreting an indication.

Alarm reference from the CS2 family

The original Yaskawa TOE-S606-2 manual for CIMR-08CS2 and CIMR-G08CS2 describes a yellow fault lamp. Table 8 lists the indications below. Applicability to CIMR-22CS2 has not been confirmed. No such code was recorded in this repair case.

Source Yaskawa TOE-S606-2 Table 8 Page 18

Request a repair for your CIMR-22CS2

Does your Yaskawa Juspeed-F CIMR-22CS2 show unusual braking behaviour or a fault indication, or does your machine fail to complete a tool change? Send us a photograph of the nameplate, a photograph of the affected indicator and a brief description of the fault. Please also tell us when the fault occurs, whether the indicator is steady or flashing, whether you require express service and whether existing parameters should be backed up.

For information on pricing and lead time, visit the Yaskawa CIMR-22CS2 product page. Learn more about our service under Yaskawa drive and motor repairs.