4

SF/E SERIES

Definition of Terms

q

Rated Functioning Temperature

Rated functioning temperature is the operating temperature of thermal cutoffs, measured using the method

specified in the safety standard. In Electrical Appliance and Material Control Law of Japan, case operation

should be within the specified operating temperature range of

± 7 ˚C. In standards that comply with the IEC

standard (such as UL, CSA, VDE, BEAB), it is called the rated functioning temperature, and should operate

within the prescribed temperature range of +0/–10 C.

It is represented by the symbol TF in the UL standard, and by the symbol Tf in the CSA, VDE and BEAB

standards.

In SEFUSE, a temperature that complies with both standards is set as the rated functioning temperature, and

is indicated on the body of the thermal cutoff.

q

Operating Temperature

Operating temperature is the operating temperature range when the thermal cutoff is made to operate inside

a constant temperature oven whose temperature is raised at the rate of 1 ˚C/min. while a detection current of

100 mA or lower is applied.

The operating temperature is a standard set by NEC and is not specified by a safety standard.

q

TH, Th. Tc (Holding Temperature)

Holding temperature is the maximum temperature at which, when applying a rated current to the thermal

cutoff, the state of conductivity is not changed during 168 hours.

It is represented by the symbol TH in the UL standard, Th in the CSA standard, and Tc in the VDE and BEAB

standards.

q

TM, Tm (Maximum Temperature Limit)

Maximum temperature limit is the maximum temperature for which conductivity does not occur again after

thermal cutoff operation.

It is represented by the symbol TM in the UL standard and by Tm in the CSA, VDE and BEAB standards.

q

Rated Current

Maximum alternating current that can pass through the thermal cutoff and that the thermal cutoff can cut off

in safety and reliability.

q

Rated Voltage

Maximum circuit voltage that the thermal cutoff can cut off in safety and reliability.