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Phone: +86 16626708626Description
3. Key Technical Specifications
| Parameter | Value |
|---|---|
| Nominal current (IN) | 30 A (TK/TB = 35 °C); 20 A (TK/TB = 45 °C) |
| Peak current (IS) | 60 A (200 ms < t < 10 s) |
| DC-link voltage (UZK) | 310 V DC |
| Output voltage | 3-phase 0–200 VAC |
| Output frequency | 0–300 Hz |
| Supply connection | Intermediate circuit from BUG feed unit |
| Control method | Analog (speed/current) |
| Protection | Short-circuit and earth-fault proof |
| Ambient temperature | 0 °C to +45 °C (operation) |
| Storage temperature | –30 °C to +70 °C |
| Dimensions (approx.) | 210 × 400 × 330 mm |
| Weight | ≈ 5–8 kg (variant dependent) |
| Mounting | Vertical in control cabinet, modular with BUG |
4. Product Introduction
The Baumüller BUS21-30/60-31-223 is a modular servo power unit from the BAUMOTRONIC BUS 21 series. It converts DC-link power into controlled three-phase AC for Baumüller servo motors rated up to 30 A continuous.
It operates in four quadrants, supports peak currents of 60 A, and delivers 0–200 VAC at 0–300 Hz. The unit mounts directly beside a BUG basic feed unit and stores drive-specific parameters in the exchangeable BEDAS module. This combination keeps downtime short when a power stage fails on older multi-axis systems still running BUS-series hardware.
BUS21-3060-31-223
BUS21-3060-31-223
5. Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to this Part | Quick Check Method | Recommendation |
|---|---|---|---|---|
| No output / motor dead | DC-link voltage missing | ❌ Low | Measure UZK at intermediate circuit rails | Check BUG feed unit and fuses first |
| Overcurrent fault LED | Short or overload on motor | ✅ High | Inspect motor cables and insulation | Replace module only after cable test |
| Earth-fault indication | Ground fault in motor or cable | ✅ High | Megger test motor + cable > 10 MΩ | Repair wiring before powering again |
| No enable / ready signal | Enable input or BEDAS issue | ✅ Medium | Verify enable voltage and BEDAS presence | Confirm BEDAS matches original drive |
| Overtemperature | Cooling or ambient high | ✅ Medium | Check heatsink temperature and airflow | Improve cabinet cooling, then retest |
| Intermittent speed control | Analog setpoint wiring | ❌ Low | Scope ±10 V setpoint signals | Fix signal wiring before module swap |
If diagnostics remain unclear, send clear photos of the front LEDs, nameplate, and diagnostic logs to technical support before ordering a replacement.
6. Frequently Asked Questions (FAQ)
Q: Is the BUS21-30/60-31-223 a direct drop-in replacement for other BUS21-30/60 variants?
A: Most electrical ratings match (30 A / 60 A, 310 VDC). The final three digits (31-223) define the regulation hardware and BEDAS configuration. Always match the exact suffix or transfer the original BEDAS module. Mismatched regulation can cause enable or current-limit problems.
Q: Can I hot-swap this module?
A: No. Kill power to the entire intermediate circuit first. Residual DC-link voltage can damage both the module and the motor. Wait until the DC-link capacitors are fully discharged.
Q: Why is a surplus unit cheaper than a new factory one?
A: Baumüller discontinued many pure analog BUS21 units years ago. New-surplus stock is unused original material that still carries full electrical performance. All units we ship are tested on a genuine BUS/BUG rack under load.
Q: Does the programming stay when I swap the module?
A: The application-specific parameters live in the removable BEDAS memory. Leave the original BEDAS in place or copy it to the replacement. Without the correct BEDAS the drive will not match the motor characteristics.
Q: What is the typical lead time and warranty?
A: Units marked “In Stock” ship within 1–3 business days. Every unit carries a 12-month functional warranty covering verified defects under normal operating conditions.
Q: Any common installation traps I should watch for?
A: Confirm the intermediate-circuit bus bars are correctly seated, the cooling airflow is unobstructed, and the enable/reset signals match the original wiring. A simple photo of the old module’s connectors before removal prevents 90 % of rework.
