Fusistor^®

Introduction

S&C’s Fusistor provides full-fault-spectrum protection for voltage, control-power, and auxiliary-power transformers. It detects and interrupts large, medium and small faults. Here’s why Fusistor is superior to other current-limiting fuses:

• Fusistor eliminates excessive voltage surges. The switching-impulse voltage never exceeds twice peak system voltage when Fusistor is applied within its voltage rating. The switching-impulse voltage of other current-limiting fuses can be three or more times their nominal voltage rating — enough to cause surge arrestor operation.
  
• Fusistor isn't voltage critical. Its switching-impulse voltage is proportional to the voltage of the circuit on which it is applied. There’s no chance of misapplying Fusistor, when used within its voltage rating.
  
• Fusistor provides superior transformer protection. Fusistor has no low-fault-current “blind spot” that leaves transformers unprotected. Its slow speed ratios provide inherently high current-surge capacity to withstand transformer magnetizing-inrush currents.
  
• Fusistor features permanently accurate, non-damageable construction. The nickel-chrome fusible element used for low-fault control is nondamageable. Age, corrosion, and vibration won’t affect its TCC accuracy. Neither will surges that heat the element nearly to the severing point. And the large-diameter, rugged molybdenum element used for high-fault control is impervious to damage by vibration or careless handling.