The motor protection device 7SK82 is a universal protection, control and automation device based on the SIPROTEC 5 system. It is specifically designed for the protection of low to medium power motors.

Typical motor protection applications include:

• Protection against thermal overload of the stator due to overcurrent, cooling problems or dirt
• Protection against thermal overload of the rotor during starting due to frequent start-ups, prolonged start-ups or a locked rotor
• Monitoring voltage unbalance or phase failure
• Monitoring the thermal state and bearing temperatures by temperature measuring
• Detection of overstressing of drives running idle for, e.g., pumps and compressors
• Detection of motor ground faults
• Motor protection against short circuits
• Protection against instability due to undervoltage

Application templates

Application templates are available in DIGSI for standard applications. They comprise all basic configurations and default settings.

The following application templates are available:

Current measurement

• Thermal overload protection for stator and rotor
• Starting-time supervision
• Restart inhibit
• Unbalanced-load protection (thermal)
• Temperature supervision
• Load-jam protection
• Overcurrent protection (non-directional) for phases and ground
• Transformer inrush-current detection

Current and voltage measurement

• Thermal overload protection for stator and rotor
• Starting-time supervision
• Restart inhibit
• Unbalanced-load protection (thermal)
• Temperature supervision
• Load-jam protection
• Overcurrent protection (non-directional) for phases and ground
• Transformer inrush-current detection
• Sensitive directional ground-fault detection for systems with isolated or resonant neutral and for detecting stator ground faults
• Overvoltage protection with zero-sequence system U0
• Undervoltage protection with positive-sequence system U1
• Fuse-Failure Monitor