Operating a DC Motor Clockwise/Anticlockwise with a Single Switch

The following post discusses the wiring connections for driving a DC motor in clockwise and anticlockwise directions with the help of a single toggle switch and a relay circuit. The idea was requested by one the interested followers of this blog. I have explained more:

Technical Specifications

We have our project in school.

Our professor asks us to design a transistor together with a relay that allows a motor to rotate clockwise and then , a switch will be press , then will rotate counter-clockwise.

In other words a single switch should be able to control the reverse forward rotation of the motor.

Thanks in advance.

The Design

A DC motor can be very simply rotated both ways in clockwise as well as in anticlockwise directions by flipping the supply inputs to it.

However the above reversing requires flipping of both of its wire polarity with the connected supply.
Therefore it cannot be done by using a single relay or switch.

However by using a couple of relays, a single switch operation becomes feasible for toggling the connected DC motor in both reverse and forward directions.

The following circuit shows the wiring details of the relay with the motor which is controlled by a transistor driver stage.

On switching power ON, the motor starts rotating in either clockwise or anticlockwise direction depending upon the wire polarity of the motor.

When SW1 is pressed, the direction gets instantly reversed and continues until S1 is switched OFF.

Actually the transistor stage is not required here, the implementation could be done simply with the relays and SW1.
More simply, the whole reverse forward operation can be conducted using an ordinary single DPDT toggle switch.