Fanuc Roboshot SV0441 Servo Alarm: Motor Overload or Excessive Current Draw — Troubleshooting Guide
Tensile data verified against MatWeb.com database & manufacturer datasheets · Last updated July 2026
Published: 2026-06-22
Fanuc Roboshot SV0441 indicates the servo amplifier has detected excessive current draw from the servo motor — typically caused by mechanical binding, increased friction in the ball screw or linear guides, or a failing motor bearing. The alarm...
Fanuc Roboshot SV0441 indicates the servo amplifier has detected excessive current draw from the servo motor — typically caused by mechanical binding, increased friction in the ball screw or linear guides, or a failing motor bearing. The alarm protects the amplifier from damage by shutting down before the current exceeds the amplifier's rated capacity. Do not simply reset the alarm without investigating the root cause — repeated resets will eventually damage the amplifier.
Alarm Details
| Alarm Code | SV0441 |
|---|---|
| Brand / Machine | Fanuc Roboshot |
| Severity | High (Machine Stop) |
| Component | Servo Motor / Amplifier |
| Affected Systems | Injection Axis, Clamp Axis, Ejector Axis |
Troubleshooting Protocol
Record the axis (X/Y/Z) and the exact current value at trip. Compare to the motor's rated continuous current. If the current is above 150% of rated, the issue is mechanical binding.
Power down (LOTO). Disconnect the coupling between the motor and the ball screw. Rotate the ball screw by hand — it should turn smoothly with minimal resistance. If it binds, the ball screw or linear guides need service.
Rotate the motor shaft by hand. It should spin freely without noise, roughness, or play. Any roughness = bearing failure. Replace the motor or send for bearing replacement.
Replace the identified faulty component (motor, amplifier, or ball screw). After replacement, run a test cycle and verify current draw is within normal range.
OEM Replacement Parts
| Part Name | OEM Part Number | Est. Price |
|---|---|---|
| Fanuc Beta iSV Servo Amplifier | A06B-6240-Hxxx | $2,500-4,500 |
| Fanuc Alpha iS Servo Motor | A06B-0xxx | $2,000-4,000 |
| Fanuc Pulse Coder Cable | A660-2005-Txxx | $150-350 |
Prices are estimated US market ranges. Contact your OEM distributor for exact pricing. {zone} = zone-specific variant.
Same Alarm on Other Machine Brands
If you operate multiple injection molding machine brands, the same fault may appear under different alarm codes:
Equivalents & Cross-References
| Equivalent / Alternate | Action |
|---|---|
| Sumitomo Demag Alarm S-03 | |
| Engel Alarm 520 | |
| Arburg Error 300 |
Frequently Asked Questions
What causes Fanuc SV0441 alarm?
Excessive current draw from the servo motor. Common causes: mechanical binding in ball screw or linear guides, failing motor bearing, misaligned coupling, or overloaded axis (trying to inject against excessive back pressure).
How do I troubleshoot SV0441?
1) Check the affected axis for free movement (disconnect motor and rotate by hand). 2) Check motor bearing for noise or roughness. 3) Check ball screw and linear guides for contamination or binding. 4) Check injection back pressure setting — excessive back pressure increases motor load. 5) If mechanical checks pass, the servo amplifier may be failing and require replacement.
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References & Industry Standards
- ASTM International. Standard Specifications for Engineering Plastics & Thermoplastics. astm.org
- UL Prospector. Plastics & Elastomers Material Database. ulprospector.com
- MatWeb. Material Property Data for Engineering Thermoplastics. matweb.com
- ISO 1043. Plastics — Symbols and Abbreviated Terms. iso.org