Product Specifications

Snap-Action Motor Protectors

The Therm-O-Disc line of Motor Protectors offers accurate and reliable protection against hazardous overheating in single phase/single voltage A/C motors. Available in a variety of product types, these motor protectors employ a snap acting, current and temperature responsive bimetal disc for proven performance over life. An internal resistance heater utilizes the effects of current to bias the operation of the bimetal disc for added thermal response. A wide range of bimetal and heater combinations are available to cover specific design requirements. This design flexibility and proven performance has made Therm-O-Disc Motor Protectors a popular choice among the leading manufacturers of fractional h.p. motors.

Features and Benefits:

• High-speed contact separation ensures long contact life.

• Current and temperature responsive for excellent design flexibility.

• Manual and automatic reset switching actions combined with a wide selection of bimetal discs and heaters to meet a variety of possible application needs.

• 100% temperature calibration and trip time tests assure high quality levels.

• The use of Statistical Process Control (SPC) techniques in all phases of manufacturing.

Type 30M – The Therm-O-Disc Type 30M SPST manual reset protector is a compact device designed for applications where inadvertent equipment restarts may result in potential hazard. The contacts may be manually reset after the control has cooled 30°-50°C below the open temperature calibration. The 30M features a “trip free” manual reset design. UL designates the 30M reset as “MI” meaning the motor protector shall automatically reset to the closed position after normal operating conditions have been restored, if the reset button is held in the reset position.

Typical uses include disposer and oil burner applications where “tripping” the device should result in the end user taking corrective action. Standard terminations are weld type connections. Male quick connect terminals, lead wire assemblies, and bimetal and heater combinations are available to meet specific requirements. This “trip free” construction means that processing the reset button will not reclose the contacts until the control has cooled.