Quick Answer

Servo motor alarms are designed to protect the machine from damage and indicate problems such as overheating, encoder faults, overload conditions, communication errors, or power supply issues.

Most servo alarms can be resolved by identifying the root cause rather than simply resetting the machine.

Common causes include:

  • Motor overheating
  • Encoder failures
  • Servo drive faults
  • Loose electrical connections
  • Excessive machine load
  • Cooling system problems

A systematic troubleshooting process helps minimize downtime and prevent repeated failures.

Why Do Servo Motor Alarms Occur?

Modern injection molding machines use servo systems to improve:

  • Energy efficiency
  • Response speed
  • Pressure control
  • Production consistency

The servo drive continuously monitors motor performance.

When abnormal conditions are detected, the system generates an alarm to protect both the motor and the machine.

Ignoring alarms can lead to costly component damage.

Common Servo Motor Alarms

While alarm codes vary by manufacturer, most alarms fall into several categories.

Alarm Type #1: Overload Alarm

Typical Symptoms

  • Machine stops suddenly
  • Servo overload warning appears
  • Reduced machine performance

Possible Causes

  • Excessive hydraulic pressure demand
  • Mechanical resistance
  • Pump issues
  • Incorrect machine settings

Troubleshooting Steps

✓ Check machine load

✓ Verify hydraulic system condition

✓ Inspect pump operation

✓ Review recent process changes

Repeated overload alarms should never be ignored.

Alarm Type #2: Overheating Alarm

Typical Symptoms

  • Servo temperature alarm
  • Machine shutdown during operation

Possible Causes

  • Blocked cooling airflow
  • Failed cooling fan
  • High ambient temperature
  • Continuous heavy operation

Troubleshooting Steps

✓ Clean cooling vents

✓ Inspect cooling fans

✓ Check room temperature

✓ Verify motor temperature

Overheating is one of the most common servo system problems.

Alarm Type #3: Encoder Alarm

Typical Symptoms

  • Position error alarms
  • Machine movement abnormalities
  • Servo startup failure

Possible Causes

  • Damaged encoder
  • Loose encoder cable
  • Electrical interference
  • Encoder contamination

Troubleshooting Steps

✓ Inspect encoder wiring

✓ Check cable connections

✓ Verify encoder condition

✓ Review alarm history

Encoder-related alarms often require careful inspection rather than immediate component replacement.

Alarm Type #4: Communication Error

Typical Symptoms

  • Servo drive communication fault
  • Intermittent machine operation

Possible Causes

  • Damaged communication cable
  • Loose connectors
  • Control system issues
  • Electrical noise

Troubleshooting Steps

✓ Inspect communication cables

✓ Verify connector integrity

✓ Check grounding system

✓ Restart control systems according to manufacturer procedures

Alarm Type #5: Low Voltage Alarm

Typical Symptoms

  • Servo startup problems
  • Random shutdowns
  • Drive fault messages

Possible Causes

  • Unstable power supply
  • Voltage drop
  • Electrical distribution problems

Troubleshooting Steps

✓ Measure incoming voltage

✓ Inspect power connections

✓ Check electrical panels

✓ Consult qualified electrical personnel if necessary

Stable power quality is essential for servo system reliability.

Alarm Type #6: Overvoltage Alarm

Typical Symptoms

  • Immediate servo shutdown
  • Drive protection activation

Possible Causes

  • Power supply fluctuations
  • Regenerative energy issues
  • Drive configuration problems

Troubleshooting Steps

✓ Verify incoming power quality

✓ Check drive parameters

✓ Inspect braking systems if applicable

Alarm Type #7: Motor Feedback Error

Typical Symptoms

  • Position instability
  • Machine movement errors

Possible Causes

  • Encoder failure
  • Feedback cable damage
  • Signal interference

Troubleshooting Steps

✓ Inspect feedback wiring

✓ Check cable routing

✓ Verify encoder performance

First Steps When a Servo Alarm Appears

When a servo alarm occurs:

Step 1: Record the Alarm Code

Always record the exact alarm code before resetting the machine.

The code provides critical diagnostic information.

Step 2: Check the Machine Manual

Different manufacturers use different alarm numbering systems.

The machine documentation should always be the first reference.

Step 3: Inspect for Obvious Problems

Look for:

  • Loose wiring
  • Damaged cables
  • Cooling issues
  • Hydraulic abnormalities

Many alarms are caused by simple issues.

Step 4: Review Recent Changes

Ask:

  • Was maintenance recently performed?
  • Were machine settings changed?
  • Was new material introduced?

Recent changes often provide clues.

Common Servo Alarm Troubleshooting Mistakes

Resetting Without Investigation

Repeated resets may hide developing problems.

Ignoring Overheating

Heat-related alarms often indicate serious maintenance issues.

Replacing Components Too Quickly

Accurate diagnosis should come before expensive replacements.

Ignoring Alarm History

Previous alarms often reveal patterns that help identify root causes.

Preventive Maintenance for Servo Systems

Preventive maintenance significantly reduces alarm frequency.

Recommended practices include:

Monthly

✓ Inspect cooling fans

✓ Check cable connections

✓ Clean ventilation paths

Quarterly

✓ Inspect electrical terminals

✓ Check servo drive status

✓ Verify grounding

Annually

✓ Review alarm history

✓ Inspect encoder condition

✓ Evaluate motor performance

Preventive maintenance is often the most cost-effective way to avoid servo-related downtime.

When Should a Servo Motor Be Replaced?

Replacement may be necessary when:

  • Internal damage is confirmed
  • Repeated failures occur
  • Repair costs become excessive
  • Critical components are no longer available

Many servo motor issues can be repaired without replacing the entire motor.

A proper inspection should always be performed first.

How DAYAMAC Supports Servo System Troubleshooting

DAYAMAC, the injection molding machine division of DAYA MACHINERY, helps manufacturers diagnose and source replacement components for servo systems.

We support customers with:

  • Servo motors
  • Servo drives
  • Encoders
  • Cooling fans
  • Electrical components
  • Spare parts sourcing
  • Technical consultation

Our team assists factories in reducing downtime and restoring reliable machine operation.

Common Questions

What is the most common servo motor alarm?

Overheating, overload, encoder, and communication alarms are among the most frequently encountered servo system faults.

Can I reset a servo alarm and continue production?

You can reset the alarm, but the root cause should always be investigated to prevent recurring failures.

Can low voltage cause servo alarms?

Yes. Unstable power supply is a common cause of servo system faults.

Does a servo alarm always mean the motor is damaged?

No. Many alarms are caused by wiring, cooling, sensors, or external system issues rather than motor failure.

How can I reduce servo motor alarms?

Regular maintenance, proper cooling, electrical inspections, and prompt troubleshooting are the most effective preventive measures.

Contact DAYAMAC

Need help sourcing servo motors, servo drives, encoders, or injection molding machine spare parts?

DAYAMAC provides:

  • Servo motor solutions
  • Servo drive components
  • Encoder replacements
  • Electrical spare parts
  • Technical support
  • Industrial Sourcing & Supply Solutions

Contact our team for assistance with servo system troubleshooting and spare parts sourcing.