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MEXICOWANDERER's avatar
Sep 23, 2016

Thermal Switch Specification Question

https://www.skycraftsurplus.com/b12mswthermalnc55degc.aspx


I am unfamiliar with this type of switch. Apparently it is of standard bi-metallic design. Care to hazard a guess as to it's amperage spec? It would be so nice to protect my 50 watt LEDs 50/36v = 1.40 amperes. The lamps utilize fans to maintain safe junction temperatures. At a buck a pop, they could be Arctic Silver epoxied right alongside the heat sink and safe the chip in a failed fan condition. And I remember someone griping about a water pump thermal issue. These are rated 10 degrees warmer but undoubtedly (?) a relay would have to be used (?)

4 Replies

  • If this switch has similar properties to say a snap-action toggle or rocker switch, would it not have a higher amperage rating at the lower 120volt usage? Say, perhaps, 150% of the 250 vac spec? These things sell for almost seven dollars US retail?
  • YES! Thank you Mr. Wizard! I got so carried away I just ordered fifteen of them! Protection for up to 150 watts of LED lighting! Now I can concentrate on making BEAST MOSFET relays for 50 amp use. Heatsink protection via gate trigger shutdown (with appropriate pulldown resistors, zener, flywheel diode, and TVS snubbing on the drain). Flop this baby into an aluminum project box with mounting ears, and...

    (waste even more money on whimsical projects)

    No! Wait! I can justify this stuff. It's recreation. It's educational. It's expensive.
  • bottom of the page microtherm B12H

    according to this link
    http://www.temperaturschalter-24h.de/manufacturer/microtherm.html

    250v-270v 6amp depending on which one it is

    i saw B12 and B12E both 6amp

    here is a pdf link
    http://www.microtherm.de/upload/mediapool/microtherm_Thermal+motor+protection_+B_en_0715.pdf

    it mentions the 12E and 12G series specs

    maybe the the 12H is discontinued

    lists cycle life at amps , and list 30amp failure mode ?
    10a/4a 10,000cycles
    13a/6a 1000 cycles
    300v peak

    i think you'll be safe at your use specs