Quote:
Originally Posted by e-mike
me too ive noticed that...i have 5 unit(v3)and the fan come to life at 95F and for a other one unit the fan begin to spin at 125f!!...(both esc had exactly the same set-up)why?????
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Well... several reasons. 1st, the calibration routine for temperature is run on the very first power-up of the MMM (which is at our lab in Kansas) -- but the temperature can vary by a few (maybe 5) degrees in the lab (depending on if its a hot day, or a cold day outside...)
2nd, the temperature sensor itself has a few degrees of tolerance.
That's why we set the temperature to a fairly low turn-on temperature. The MMM can run up to 120C (250F) on the heat sink during normal running with no issue at all, and can run up to 200C chip temperature (close to 400F) before any real internal damage starts to happen. We often reflow the solder on the transistors during extreme power testing, (where the solder becomes liquid under the transistors) and in most cases the MMM just keeps right on working normally (until the processor clock shuts down... that happens when the processor internal temperature gets to about 180C -- but that can take a few seconds for the heat to conduct to the processor core. If the processor shuts down, everything just cools off and it restarts a few seconds later, with no issues.)
For production units, we set the shutdown temperature (thermal) at about 90C-100C (about 195F-210F.) I haven't heard of anyone (yet) thermalling a MMM. (let me know if I'm wrong about that!)