How a relay can change the direction of a motor?

Question

Can anyone answer this question for me?
Thanks in advance!

Answer 1

if we are talking about a DC motor then reversing polarity will change direction.

This is done with a DPDT (Double Pole Double Throw ) relay.

A DPDT relay has two set of contacts one may used for the positive side and the other for the negative

Each set of contacts has three connections

NO - Normally Open
C - Common
NC - Normally Closed (no power applied to coil this is the normal state)

Connect a positive lead from the battery to one C connection and the negative to the other C (Common) connection.

Then using the NC (Normally closed connections) Connect a positive and negaive wire from the motor to one of the NC connections.
This will make the motor spin in one direction.

Now make another connection from one of the NC connectors and cross the wire over onto the other Pole NO connector. Repeat for the other polarities wire. This will make a cross or X shaped connection between the NO and NC connections.

Energizing the coil will shift the armature of the relay causing the
connection between the Common and NC to open, then an electrical connection will be made between the C and NO connections .

The battery voltage will now travel out of the relay and down the crossed wires. You now have reversed the polarity and direction to your motor.


You will need to a a power switch or another relay between the battery and the direction relay so as to be able to stop the motor.

Answer 2

Suppose that the motor is three phase. Reversing the phase rotation by swapping any two of the three wires will reverse the direction of the motor, and a relay can do this. A similar stunt is used on single-phase motors, such as are used in my garage door opener. The motor has two windings, one of which is fed directly from the line and one through a capacitor which introduces a phase shift. Two relays are used, one to run the motor in each direction, by determining which winding gets the direct line and which goes through the capacitor.

Answer 3

A motor can be wired to run in a certain direction all the time. Then, if it is wired properly, a relay could pull in, introducing a higher potential in the opposite direction. You don't have to kill power on the other lead of the motor, it just has to be higher than the other leg.

Kind of hard to explain without drawing it out.

Answer 4

A relay is an electrical switch that opens and closes under control of another electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. It was invented by Joseph Henry in 1835. Because a relay is able to control an output circuit of higher power than the input circuit, it can be considered, in a broad sense, to be a form of electrical amplifier.

If the R,Y,B CONNECTION are reversed while taking relay in line , direction will be reversed.

Answer 5

simply by changing the polarity and the voltage supplied to the motor which makes it turn clockwise or counterclockwise

Answer 6

I second Christ..
But can u draw and email - attach it pls.., thanks