Quote:
Originally Posted by 97 SL320
The second less obvious function is shorting motor leads just after dropping the switch stalls the motor to prevent coasting / overshoot. As a motor is coasting down, it is acting as a generator so applying an electrical load creates mechanical load.
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This is true in the case of a fan or blower, which have considerable momentum and can coast for some time. But when a window motor reaches the end of it's travel, it's stopped dead, so it can't become a generator. At that point, it becomes an inductive load which consumes electricity and produces heat. The heat will trigger a thermal switch which breaks power in case the switch isn't released. When the switch opens, stored energy in the motor winding is either dumped back into the harness as a reverse spike or released as heat.