SCR crowbar

This is an SCR crowbar alternative; to the solar HVIsolator circuit, which should be much cheaper and simpler to implement. It uses SCRs instead of a mosfet, (a) zener diode(s) to provide the gate current, and pull-down resistors to prevent the scrs from switching on before the overvoltage condition is met. In order to limit the peak current a number of 1 ohm 10W resistors will be placed in parallel, in series with the SCRs. These act to reduce the peak capacitive discharge (from the motor controller supply capacitors) current through the SCRs, which may be too large given this capacitance is large (just under 2 mF).