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Thermal protectors provide protection in high-voltage apps

Posted: 24 May 2005 ?? ?Print Version ?Bookmark and Share

Keywords:thermal protector? selco products? ub8p? ub81p?

The self-hold thermal cut-out and thermal protectors from Selco Products are designed to provide overheat protection in high-voltage applications. With a high 16A capability, the new UB8P and UB81P models are suitable for thermal overload protection in a broad range of applications including space heaters, dishwashers, mixers, blenders, grinders and other electronic appliances.

The body of these surface-mount devices is manufactured of phenolic resin and features a new patent pending partition wall design that isolates the switch from the main body. The company said this new design effectively controls arcing that can cause a break in voltage contact (particularly in 250 V applications), and ensures continuous operation to the set point. The UB81P features a reinforced PBT enclosure for dust-proof applications, while the UB8P has an exposed bi-metallic element for high accuracy and fast response to ambient air temperature.

Both models incorporate a "self-hold" non-self resetting function that provides a high level of operational safety, especially in appliances with moving parts. The "self-hold" function ensures that after the element reaches its pre-set open temperature, the internal heater activates to maintain a self-regulating temperature, preventing the switch from resetting until the user disconnects the power.

Measuring 31.5-by-6.5-by-4.2mm, the UB8P and UB81P are manufactured with a built-in ceramic PTC (positive temperature coefficient) self-regulating heating element, which is positioned directly next to the bi-metal sensing switch. This design provides efficient insulation and fast thermal response time compared to units where the heater is mounted externally to the thermostat, said the company.

Contact ratings for the devices are 16A at 125V and 10A at 250Vac to 6,000 cycles. The operating temperature set range is 75C to 145C. Temperature tolerances are -5, -7 and -10C with a standard differential of 30C 15C.

Agency approvals include a UL rating of 16A at 125Vac, 6,000 cycles resistive down to 125C and a European rating of 10A (5A) at 250Vac, 6,000 cycles resistive (inductance) down to 125C.

The UB8P/UB81P is priced from $1.50 each in quantities of 10,000. Delivery is six to eight weeks.

- Gina Roos


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