WhatsApp: +86 16626708626
Email: 
Phone: +86 16626708626Description
Key Technical Specifications
| Parameter | Value |
|---|---|
| Motor Type | AC synchronous servo motor, 3-phase, self-cooled, construction type A |
| Frame Size | 3L (Size 3, Large) |
| Rated Power | 0.68 kW |
| Rated Current | 1.62 A |
| Stall Torque | 2.5 Nm |
| Stall Current | 1.8 A |
| Rated Voltage | 330 V |
| Max Speed | 3,000 rpm |
| Insulation Class | F (max 155°C / 311°F) |
| Protection Class | IP64 |
| Feedback Device | EnDat single-turn encoder, 512 lines |
| Approx. Weight | ~12–13 lbs (5.4–5.9 kg) |
| Approx. Dimensions | ~15–17 in length x 7–8 in width/height (motor-dependent on shaft/connector config) |
Specs sourced from confirmed nameplate data on the closely matching 8MSA3L.E0-32 unit. Suffix “-31” vs “-32” is expected to share these core electrical ratings, but connector orientation and possibly shaft-end configuration differ — verify against the physical nameplate or B&R drawing before final fitment.
Product Introduction
The B&R 8MSA3L.E0-31 is a Size 3 Large-frame synchronous servo motor from B&R’s legacy 8MS series, delivering roughly 2.5 Nm stall torque at up to 3,000 rpm with EnDat single-turn encoder feedback. It’s built for ACOPOS-driven axes on machines running the earlier 8MS motor generation, before B&R moved to the inductive-encoder 8MS-4 naming scheme.
The “-31” suffix on this frame/encoder combination should share the same core electrical rating as the “-32” variant we’ve confirmed nameplate data on, but B&R’s two-digit suffix codes on 8MS motors typically track connector orientation or shaft configuration. If you’re matching a specific machine, confirm the exact suffix against what’s coming off the axis — don’t assume -31 and -32 are interchangeable without checking.
8MSA3L.E0-31
8MSA3L.E0-31
Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to this Part | Quick Check Method | Recommendation |
|---|---|---|---|---|
| Axis faults on power-up with encoder error | Encoder wiring fault or connector seating | ❌ Low | Check encoder cable continuity and connector seating at both motor and ACOPOS ends | Inspect wiring before assuming the motor’s encoder has failed |
| Drive throws overcurrent/overload fault | Mechanical bind or load exceeding the 2.5 Nm stall torque rating | ❌ Low | Disconnect the load and jog free — if clean unloaded, the fault is mechanical | Check the mechanical load path before replacing the motor |
| No rotation, encoder reads correctly, drive shows no fault | Winding open or stator fault | ✅ High | Measure phase-to-phase stator resistance and check for shorts to case (compare against nameplate/datasheet reference if available) | If resistance is open or grossly abnormal and wiring checks clean, the motor winding has failed |
| Motor runs hot at rated load | Duty cycle exceeding the motor’s thermal rating for this frame size | ❌ Low | Compare actual RMS torque demand against the 0.68 kW / 2.5 Nm rating | Confirm the application’s torque profile before condemning the motor |
| Connector doesn’t seat correctly on replacement | Suffix mismatch (-31 vs -32 connector/shaft variant) | ✅ High | Compare the physical connector orientation and shaft end against the removed motor | Confirm exact suffix match before ordering a replacement if this happens |
If you’re troubleshooting at 3 AM: check encoder cable seating first on any legacy 8MS unit — connectors on these older motors are a common source of intermittent faults that look like a motor problem but aren’t.
Frequently Asked Questions (FAQ)
Is “-31” the same motor as “-32,” just a typo away?
Not necessarily. On 8MS motors, that trailing two-digit suffix generally tracks connector orientation or shaft-end configuration rather than being a version number like on the 8LS line. The core electrical rating should match, but the physical fit might not — confirm against your existing motor or drawing before ordering if exact fitment matters.
Will my ACOPOS drive recognize this motor without extra configuration?
This depends on your drive’s motor database and firmware revision for the legacy 8MS naming scheme. If your drive was commissioned with the original motor, it should already have the correct entry — confirm before replacing if you’ve since updated ACOPOS firmware.
Why don’t you have full B&R datasheet numbers for this exact part?
B&R’s currently published online catalog data covers the newer 8MS-4 generation (inductive encoder naming). This is a legacy 8MS unit, so we’re relying on confirmed nameplate data from a closely matching unit rather than an official published datasheet — we’ll confirm the exact numbers against the physical nameplate before it ships.
Why is this priced below current B&R equivalents?
This is New Original / New Surplus stock of a legacy motor generation — sourced through the secondary market, which typically runs below current-catalog pricing for the newer 8MS-4 replacement motors. If your machine still runs the original 8MS generation, this gets you genuine hardware without a drive/motor requalification project.
What’s your testing process on this unit before it ships?
Inbound visual inspection for shaft and connector damage, a stator resistance check, and confirmation of the nameplate part number and suffix against your order. Tell us upfront if you need a powered functional test on an ACOPOS bench before it ships.
