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Key Technical Specifications
- Manufacturer: B&R Automation
- Part Number: 8YS-K0055R0.005-0
- Series: B&R 8YS synchronous servo motor series
- Product Type: Permanent-magnet synchronous servo motor
- Reported Output Power: 0.55 kW; verify against the actual motor nameplate
- Reported Current: 4.04 A
- Reported Torque: 3.77 Nm
- Reported DC Bus Reference: 640 VDC
- Ingress Protection: IP65
- Reported Maximum Speed: Up to 6,000 RPM; verify nameplate and matched drive data before installation
- Reported Weight: Approximately 6.1 kg / 13.45 lb
- Motor Feedback: Exact encoder/resolver and feedback variant must be verified from the installed motor nameplate
- Brake Option: Confirm whether the actual unit includes a holding brake before ordering
- Manufacturer Status: Discontinued / legacy spare part
Independent industrial parts databases consistently list 4.04 A, 3.77 Nm, 640 VDC, and IP65 for the exact part number. Public listings conflict on speed and other configuration-dependent values, so do not publish a fixed RPM, encoder type, winding variant, or brake configuration without an original B&R datasheet or photographs of the motor nameplate.
Product Introduction
The B&R 8YS-K0055R0.005-0 is a compact B&R 8YS-series synchronous servo motor for controlled industrial motion axes. It is used with a compatible B&R servo drive for position, speed, and torque control in packaging equipment, indexing systems, feeders, handling machines, and other machinery that requires fast acceleration and repeatable motion.
This exact 8YS-K0055R0.005-0 motor is commonly specified as 4.04 A, 3.77 Nm, 640 VDC, and IP65. Its complete suffix must match the failed motor. Confirm the mechanical flange, shaft, connector arrangement, feedback system, holding-brake option, and servo-drive motor parameters before ordering.
8YS-K0055R0.005-0
8YS-K0055R0.005-0
Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to This Part | Quick Check Method | Recommendation |
|---|---|---|---|---|
| Servo axis will not enable | Safety torque off active, drive fault, missing control supply, feedback fault | ❌ Low | Read the servo-drive fault code and confirm the safety circuit status before touching motor wiring | Diagnose the drive, safety relay, and 24 V control circuit before replacing the motor |
| Motor does not rotate when the drive commands motion | Holding brake engaged, mechanical jam, torque limit, missing motor phases | ✅ High | With lockout applied, check whether the shaft rotates freely when uncoupled; during an enable command, measure brake voltage at the motor connector | Verify brake wiring and mechanics. Replace the motor only if the brake or rotor is proven faulty |
| Drive reports encoder, resolver, or feedback fault | Damaged feedback cable, connector contamination, wrong motor variant, internal feedback failure | ✅ High | Power down, inspect connector pins and cable strain relief; substitute a known-good feedback cable where possible | Check the cable before replacing the motor. Feedback cables fail more often than the internal sensor |
| Drive trips overcurrent immediately after enable | Shorted cable, motor winding fault, drive output-stage failure, incorrect motor data | ⚠️ Medium | Disconnect the motor cable at the drive and perform the OEM-approved isolation test; compare results using a known-good motor if available | Determine whether the fault follows the drive, cable, or motor. Do not use an unapproved high-voltage test on encoder electronics |
| Axis runs in the wrong direction after replacement | Incorrect commutation/feedback setup, motor parameters not restored, phase wiring error | ✅ High | Run a low-speed supervised jog and compare commanded versus actual direction in the drive diagnostics | Load the correct saved motor configuration and verify direction before coupling the machine load |
| Axis hunts, vibrates, or misses position | Tuning issue, loose coupling, load change, feedback noise, mechanical backlash | ⚠️ Medium | Check actual position deviation and torque trend in the servo software; inspect coupling and gearbox backlash | Restore backed-up tuning and inspect mechanics before declaring the motor defective |
| Motor runs hot during normal production | Excess load, poor tuning, high duty cycle, bearing wear, restricted cooling | ✅ High | Trend torque/current and motor temperature over a production cycle; compare with a healthy axis if possible | Reduce the load or correct tuning first. Persistent heat at normal load indicates possible winding or bearing damage |
| Shaft feels rough or makes noise with power removed | Bearing contamination, bearing wear, crash damage | ✅ High | Isolate all power, uncouple the load if practical, and rotate the shaft by hand for roughness or binding | Do not continue production with bearing noise. Schedule replacement or qualified servo-motor repair |
| Position shifts after a motor swap | Incorrect encoder type, lost reference, coupling slip, incorrect homing data | ✅ High | Compare drive parameters, home offset, electronic gearing, and coupling marks with pre-removal records | Re-home at reduced speed and validate the full travel envelope before automatic operation |
Do not diagnose this motor from the drive fault code alone. A damaged feedback cable, an inactive safety circuit, or a brake supply issue can produce symptoms that look like motor failure. Send technical support clear motor-nameplate photos, connector photos, the servo-drive fault history, and the old drive parameter backup if the fault remains unresolved.
Frequently Asked Questions
What is the B&R 8YS-K0055R0.005-0?
The B&R 8YS-K0055R0.005-0 is a B&R 8YS-series synchronous servo motor. It works with a matched servo drive to control axis position, speed, acceleration, deceleration, and torque. Available industrial listings identify the exact motor as 4.04 A, 3.77 Nm, 640 VDC, and IP65.
Is the 8YS-K0055R0.005-0 still manufactured?
Treat it as a discontinued legacy spare part. Current market supply is generally secondary-market inventory: new surplus, unused inventory without original outer packaging, used stock, or refurbished units. Confirm actual availability and lead time before releasing a purchase order because stock can change quickly.
Can I substitute another B&R 8YS servo motor?
Not without checking every relevant detail. The replacement must match the complete part number, electrical winding, motor feedback type, flange and shaft geometry, connector orientation, brake option, rated torque, speed range, and the existing servo-drive parameter set. A motor that physically bolts onto the machine can still fail to enable if its feedback configuration differs.
Is the motor really rated at 6,000 RPM?
Some industrial listings report up to 6,000 RPM for this model, while other online sources report different speed values. Do not treat any web-listed RPM as final. Use the physical nameplate and original B&R documentation for the exact unit, then confirm that the installed drive and mechanics allow that speed.
Can I hot-swap this B&R servo motor?
No. Power down the servo system, apply lockout/tagout, wait for the drive DC bus to discharge as specified by the drive manufacturer, and verify absence of voltage before disconnecting motor or feedback cables. Do not disconnect a motor under power. It can damage the drive output stage, create an electrical hazard, and cause unexpected axis movement.
Will I lose the machine program when replacing the motor?
Normally, no. The PLC application usually remains in the controller. However, the servo drive stores or references motor-specific settings such as current limits, feedback configuration, homing data, position scaling, commutation values, brake timing, and tuning. Back up the entire servo-drive project before removal. Then verify direction, feedback, homing, travel limits, and load operation at low speed before returning the axis to automatic production.
Why is a New Surplus motor cheaper than factory stock?
New Surplus usually means unused original stock sold outside the normal factory channel, often from excess inventory, plant shutdown spares, cancelled projects, or discontinued-machine inventories. It may be less expensive because it is not supplied under a current OEM distribution program. Ask for actual photographs of the motor nameplate, shaft, connector faces, packaging, serial number where available, condition statement, and written warranty terms before buying.
What supplier testing should I request?
For New Original / New Surplus stock, request part-number and nameplate verification, visual inspection for corrosion or rework marks, connector inspection, shaft-rotation verification, and clear packaging photos. For Refurbished units, request testing on a compatible B&R servo drive with verified feedback recognition, low-speed rotation, direction confirmation, current monitoring, brake operation if fitted, and a documented load run where practical. Ask for test photos, video, and the written test report before shipment.
