The expense of your desk motor burning out has a cap though. The expense of a utility controlling device not shutting off after intentionally being stressed/hacked is potentially very high and may require human intervention to detect, maybe they decided it’s better if the device fails under this type of abuse which will bring humans into the loop to detect the problem.
Not turning off would be a bad protection, but it could also decide not to turn on. Something as simple as only allowing three remote turn-on commands every hour, anything beyond that requires a physical override.
The device not switching on when overheated could attract humans' attention, too, without the need to replace the device, which may be an involved process for high-power circuits.
Not the poster, but they are right. The linear motors in standing desks are not made for permanent use (they would heat up too much if used that long). In the datasheet they will typically put something like "can be used for maximum of x minutes within x+y minutes".
The desk controllers I have seen check for that limit (as one should).
Every controller should reject input that leads to destruction, especially if the input is wireless or comes over network.
Plenty of devices have protective circuits. My cheap paper shredder is very aggressive about heat management - once it detects it's heating up too much, it'll shut itself off for ~30 minutes to cool down. That state somehow[0] persists even if you unplug it, so I had to learn to feed it paper at the right pace, 'lest I'll be taking half-hour breaks every 2-3 minutes of shredding.
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[0] - The shredder is of the cheaper kind, and shows zero indication of any computer on board, so I'm assuming overheating shutoff is charging up some capacitor that's grounded via a high-resistance path and discharges at a known rate.
I have a shredder that cuts out when it overheats too. It's a PTC thermistor controlling a relay, the thermistor is glued to the motor housing and the relay coil contact is wired through it. When it heats up too much, the resistance increases to the point that the relay is no longer receiving enough current, and it de-energizes and opens its contacts, breaking the motor's power supply.
No, you got it right. It's a bi-metal in all electric motors that I'm aware of that have overheating protection.
I actually had a dangerous situation here once in a big compressor motor that had a faulty soft-start circuit, that caused the bi-metal contacts to fuse so the protection no longer worked. By the time I noticed the compressor motor was way too hot to touch.
Does bimetallic strip have some kind of passive hysteresis? Because what I observed with my shredder is that, if the overheat protection kicks in, it won't turn on for the next 20-30 minutes. You can flip the switch, or even unplug it from mains, doesn't make a difference - it won't turn on for almost half an hour.
Now, that could be explained by e.g. the engine itself having enough thermal capacity to keep the shutoff switch active for a while, except... if you are careful and do small pauses between shreddings, you can keep going indefinitely - and those pauses don't feel enough to let the engine cool if that was the only thing that mattered.
Like, you shred something for 3 minutes straight and get 30 minutes cutoff, vs. shredding something for 1 minute, then 30 seconds break, then 1 minute, then 30 seconds break, ... and you can keep going like that for hours.
My freaking standing desk has protection if I go up and down too much within a certain period of time.
Like I said, I have zero trust this meter is accurate when it doesn't even have simple protective circuitry.