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Unread 05-04-2009, 11:49
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AKA: Alex
FRC #1024 (Kil-A-Bytes)
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Re: Victor Vs Jaguar

Quote:
Originally Posted by gburlison View Post
It seems that the Victors draw more current from the PWM line.
Truth.

All of IFI's motor drives are opto-isolated on the signal input to protect your controller board from the slings and arrows of brushed motor noise (i.e. reverse polarity voltage spikes on brush contact release, generator effect during duty cycle off time).

The current draw comes from the opto-isolators, which put an air gap between you and anything that could come in contact with the motor. The current you input on the PWM signal line runs an LED, which is pointed at a photo diode (think teeny weenie little solar cell) or photo transistor(more popular, transistor with base driven by photon input).

The photo diode or photo transistor's output signal matches the input signal, but with near infinite impedance (for our intents and voltage ranges) back to the signal source thanks to the air gap (between the LED and sensor) acting as a high value resistor between the signal source and the speed controller's circuitry.

If you've ever jammed a drive motor or other large motor coupled to a lot of inertia from 254 to 0 in one 25.4ms update period, you probably have these little guys to thank for saving the life of your RC.

-q
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