A washing machine is driven by a single phase fractional motor. What makes it run reverse foreword?

Many older washing machines have a sort of simple transmission or gear train. An electrical solenoid, or stepper solenoid can switch the unit into differen modes including reverse and agitate when a control timer signals it to do so.

Newer washing machines don't use mechanical transmissions. Instead they use motor drive electronics and an AC induction motor. The drive electronics can control the speed and direction of the motor very efficiently.

-rdot.