Using accelerator pedal to select different motor circuits interested me.
Simulator values not correct but to show basic circuits. The motor is a compound wound motor with a variable shunt resistor controlling the current of the motor shunt field.
Left circuit is zero current through motor shunt field with wire resistor (stainless steel wire resistor to handle heavy loads) in circuit and batteries in parallel hook up.
Depressing the accelerator pedal moves cam controlling microswitches to remove wire resistor from circuit and change batteries from parallel to series circuit.
In Popular Mechanic January 1973 on page 124.
https://books.google.com/books/about/Popular_Mechanics.html?id=udQDAAAAMBAJ#v=onepage&q&f=false
