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Old 01-08-2015, 07:54 PM   #1550 (permalink)
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Originally Posted by freebeard View Post
I think everyone is filtering what is really going on through a Dominate Paradigm. The guy who figured this all out was Steinmetz. It's described in the first hour of Eric Dollard's History and Theory of electricity.

Meanwhile, I keep bumbling along—I see the current episode of EVTV addresses cases of transmission failure in conversions (and Teslas?), and suggests that they're built to absorb power that 'spools up' over ~500-800ms, while the electric controller can force full power in ~5-10ms, leading to shock failures. It's at 1:25:30 as part of a typically long-winded discussion of sizing motors and multi-gearing vs single speed.
Thats because most controllers are VSI (voltage source inverters). For an induction motor any small percentage of error on the slip angle can cause huge amounts of torque for a short duration. I had some regeneration control issues due to that as well. An error in the control loop or the field building up very fast during regeneration could cause short bursts of very high torque.

The solution is to use a VSI, but add a cycle by cycle current limit, which is generally implemented in hardware. (software can generally do average current only). I have that on my TODO list for my inverter.
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