Simplify the following text for a Grade 6 native English-speaking person.
Original: All the driver had to do was select low , medium or full speed ( called `` shunt '' , `` series '' and `` parallel '' from the way the motors were connected in the resistance circuit ) and the automatic equipment would do the rest .
Simplified: All the driver had to do was select low , medium or full speed . These speeds are called shunt , series and parallel from the way the motors were wired .