The Bourns® Multifuse® Polymer PTC (PPTC) Resettable Fuses MF-RM Series are the first of Bourns® Multifuse® PPTC devices designed to operate in mains rated AC circuits of 120Vac and 240Vac.
Traditionally, polymer PTCs have been targeted at DC circuits that operate at less than 72V, but the Model MF-RM Series opens up a whole new application segment for polymer PTCs.
Previously, only overcurrent protection devices such as one-time fuses and thermal switches were seen on the primary side of transformers. However, the new Model MF-RM Series now allows AC circuits to gain the benefits of resettable fuse protection. Resettable fuses bring reliable overcurrent and overtemperature protection at values close to the circuit operating current. This allows for tighter protection without the problems associated with nuisance trips.