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the lack of a blocking diode was my first suspicion, but after looking at the switch and reading the tch articles on the z-shot website, i don't believe that was the issue here. i agree that inductive loads should be shunted thru a diode to protect related electronics as the inductive spike can be in the millions of volts. systema uses a dynamic braking system for there motor, which can simply be a resistor engaged across the motor terminals to dissipate the cemf present as the motor continues turning on inertia after the running voltage is removed. this braking system, couple with the spring load, will reduce the cemf drastically, leaving the collector/emitter junction the job of blocking the remaining spike. this may have led to a failure as well, but it's impact was negligable compared to the other problem. as far as diodes go, systema should use a seperate blocking diode system to accompany thier electronics, but it would have to carry the full start and run current of the motor, and this would be impractical due to the size of components required. their system overall is good, with the issue being mainly on the switch board. i am interested to see the reliability of the repair, but if factory assembled switches generally last, this one is far better.
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