Yaskawa USAIKM-50-BK33-C AC Servo Motor – Repaired by Us for Over 10 Years

04.05.2025 by Viktor Siebert

Yaskawa USAIKM-50-BK33-C AC Servo Motor – Repaired by Us for Over 10 Years

Customer Experience Report – How the Motor Came to Us

“The following report was kindly provided by one of our customers.”

Sudden Failures Despite Proven Technology

We are a medium-sized manufacturing company from Ungary specializing in CNC machining. Among other equipment, we operate an older CNC machining center that has served us reliably for years. At the heart of this machine is a Yaskawa spindle motor USAIKM-50-BK33-C paired with the UTMSI-10AAEAZM encoder. This drive system enabled precise 3-shift milling and drilling operations for a long time – until problems began to arise.

“Spindle Alarm – Encoder Signal Lost”

It started with random machine stoppages. Initially, the CNC control showed occasional encoder errors – alarm codes indicating a loss of spindle feedback. Our technicians replaced the motor cables and checked the connectors, but the issue reoccurred. Then, during a production run, the spindle stopped completely, and the control system displayed: “Spindle Alarm – Encoder Signal Lost.”

The Cause: Water Damage Due to Blocked Drainage

After removing the motor, we were shocked: water was dripping from the housing. Moisture was visible inside the terminal box and near the encoder. Further inspection revealed that the coolant drainage system was clogged. Over the years, residue and fine metal dust had blocked the drainage channels. As a result, water collected inside the motor housing, eventually causing damage to both the encoder and the bearings.

Spare Parts Discontinued – What Now?

Replacing the motor with a new one wasn’t financially or technically viable. And spare parts from the manufacturer? Discontinued. Even the encoder UTMSI-10AAEAZM was no longer available. Things looked bleak – until we found Industrypart GmbH in Bensheim, a company specializing in Yaskawa spindle motors.

The Repair at Industrypart – Fast, Professional, Thorough

Quick Diagnosis and Transparent Communication

We immediately felt understood – the technician knew this type of issue and asked specific questions like: “Is there water in the motor housing?” That gave us the confidence to send in the motor. The next day, we received a clear diagnosis: damaged encoder, worn-out bearings, and failing seals. But also some good news: they had a solution!

Custom-Developed Encoder Replacement

Since the original encoder was no longer available, Industrypart developed a custom replacement encoder system precisely matched to our motor. Modern sensor technology was integrated into the existing housing – fully compatible with the CNC system, with no changes required.

Complete Overhaul with High-End Components

In addition to the encoder, the entire motor was overhauled:

Hybrid ceramic bearings replaced the old ones
Thorough cleaning of coolant and drainage channels
All seals replaced
Full load testing up to 12,000 RPM, including vibration and thermal analysis

Back in Operation – Like New, or Better

After around 10 days, we had the motor back – freshly painted, fully tested, and ready to run. Reinstallation went smoothly. The first test run showed: smooth operation, precise feedback – and we even felt the spindle was quieter than before, likely due to the new bearings. The machine has since run flawlessly for months.

Customer Conclusion – A Smart Investment

We’ve learned a lot: a clogged drainage line can cause major issues. And most importantly – there are specialists like Industrypart who can still help with complex, discontinued systems. The encoder solution they developed gave our Yaskawa motor a second life.

Thank you to the team in Bensheim!

Technical Data for the Yaskawa USAIKM-50-BK33-C Spindle Motor

Motor Highlights at a Glance

Series: Yaskawa USAIKM
Continuous Power: 6 kW
Operating Voltage: UVW ~200 V AC
Rated Current: 65 A
Torque: 11.5 Nm
Max. Speed: up to 12,000 RPM (depending on version)
Cooling: Liquid cooling with drainage system
Shaft Diameter: 28 mm
Weight 34,6 KG
Encoder: UTMSI-10AAEAZM, 1024 pulses/rev

The encoder is integrated within the motor and provides precise speed and position feedback. Since it has been officially discontinued by the manufacturer, we developed a compatible in-house replacement solution.

Typical Applications

These spindle motors are commonly used in:

CNC machining centers
CNC lathes
Milling and special-purpose machines

They are found in machines from Matsuura, Brother, Hitachi Seiki, Hurco, Miyano, and Enshu, among others – all known for precision and reliability. The motor’s high speed capability and compact design make it ideal for fast, accurate machining.

Maintenance Tip: Don’t Underestimate Drainage Systems

Especially in water-cooled motors like this one, regular checks of the drainage and coolant channels are essential. Over time, buildup can block these systems, leading to severe internal damage.
Our recommendation:
+ Annual inspection and cleaning of cooling and drainage paths
+ Seal replacement during major maintenance intervals