Siemens SIVACON S8 Error Code 8PV-E11

Siemens Electrical Major Voltage

Model: SIVACON S8 | Code: 8PV-E11

Applicable Systems
SIVACON S8

Symptoms

The bus voltage has dropped below 85% of the rated 480V, reaching 408V. The undervoltage relay trips and disconnects the bus to protect connected motors.

Possible Causes

  • Supply transformer overloaded, causing voltage sag under heavy load
  • Loose or corroded bus connection causing voltage drop
  • Large motor starting inrush causing temporary voltage dip below the relay threshold
  • Power factor correction capacitor bank failure causing increased reactive current

Troubleshooting Steps

  1. Step 1: Measure the three-phase bus voltage at the main incoming terminals
    Voltage should be 456-504V (480V +/-5%); if below 456V, investigate the supply
  2. Step 2: Check all bus connections for tightness using a calibrated torque wrench
    Tighten to the manufacturer's torque specification; look for discoloration from heating
  3. Step 3: Review the load profile to identify if a large motor start caused the trip
    If motor inrush is the cause, consider a soft starter or VFD to reduce starting current
  4. Step 4: Test the power factor correction capacitors for capacitance value and integrity
    Replace any failed capacitor cans; verify the bank is properly fused

How to Reset

Reset: After the bus voltage is restored above 460V, reset the undervoltage relay and close the main breaker.

Common Replacement Parts

  • Undervoltage relay: Adjustable, 70-90% of rated voltage (Set to 85% for motor protection)
  • Power factor capacitor: 3-phase, 25 kVAr, 480V (Match to existing bank rating)
  • Soft starter: 3-phase, 480V, motor-rated (Size to motor FLA x 1.15)

Frequently Asked Questions

  • Q: What causes voltage sag?

    Large motor starts (6x FLA inrush), transformer overload, loose connections, and utility-side faults are the most common causes.

  • Q: How do I calculate voltage drop across a connection?

    Measure voltage at both ends of the connection under load. The difference is the drop. A drop exceeding 3% indicates a problem.

  • Q: What is the power factor correction target?

    Aim for 0.95-0.98 lagging. Over-correction to leading power factor can cause resonance and overvoltage.

Related Siemens Fault Codes

Source: OEM Technical Manual

Category: Electrical