CANTHERMDF240S

The CANTHERM DF240S is a non-resettable SDF-series Thermal Cut-Off (TCO) with a rated functioning temperature Tf of 240C, holding temperature Th of 200C and axial construction for permanent circuit interruption when the specified safety temperature is exceeded.

Technical description

The DF240S uses an organic thermal element. When temperature reaches the rated functioning temperature Tf of 240C, the thermal element operates the mechanism and the contacts open permanently. The device is not resettable and must be replaced after operation. Maximum continuous holding temperature Th is 200C. Maximum overshoot temperature Tm is 290C under VDE and 260C under UL. SDF-series Tf tolerance is +0/-5C.

At 250VAC, the SDF series is rated at 10A under UL/cUL, while other series approvals permit higher current ratings up to 15A depending on the applicable standard and approval. Certified designs must use the rating corresponding to the required approval.

Typical applications

Thermal protection in household appliances, heaters, power supplies, transformers and coils, electric motors, office and telecommunications equipment, electronic circuits and other equipment requiring permanent circuit interruption under abnormal overheating conditions.

Compatibility note

Tf must not be selected solely from the appliance maximum operating temperature. Th, residual heat after opening, current-related self-heating, installation position and required certification must also be considered. Leads should not be bent closer than 3mm to the body. During soldering, a heatsink should be used on the lead and the cutoff should not be heated above Tf-24C. The metal portion is electrically live and may require insulation.

Frequently asked questions

Does the fuse reset after operation?
No. It is a one-shot thermal cutoff and must be replaced.

What is the rated functioning temperature Tf?
240C with SDF-series tolerance of +0/-5C.

What is the holding temperature Th?
200C, the maximum continuous exposure temperature during operation.