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What is one way we reverse the current in a DC motor?
DC motors, like AC motors, can be configured to turn in either direction. Their direction can be easily controlled by inverting the polarity of the applied armature voltage by reversing the armature leads. This works with shunt, series, and compound wound DC motors.
How is the rotation direction of DC machine reversed?
Simply put, DC motors can turn in either direction (clockwise or counter-clockwise) and can be easily controlled by inverting the polarity of the applied voltage. If the voltage continues to be applied, the motor will start again rotating according to the voltage polarity.
How does rotation occur in BLDC motor?
With a BLDC motor, it is the permanent magnet that rotates; rotation is achieved by changing the direction of the magnetic fields generated by the surrounding stationary coils. Since the rotor is a permanent magnet, it needs no current, eliminating the need for brushes and commutator.
How does a reversible DC motor rotate clockwise?
This shows that in order to make the motor rotate clockwise, we must reverse the flow of current (i.e. changing the flow of current changes the direction of the force by 180 degrees). Of course, the direction of current is controlled by the polarity of the voltage.
Can a motor be run in the counterclockwise direction?
To run the motor in the counterclockwise direction, it is not enough to swap around two phases at any point. This would produce the same relationships as described above. In order to keep the transient current surge from star to delta connection as small as possible the wiring must be arranged as in Figure 5.
Can a DC motor be used in both directions?
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 directions. The following circuit shows the wiring details of the relay with the motor which is controlled by a transistor driver stage.
When does the motor turn clockwise when the terminals are connected?
The motor also turns clockwise when the terminals are connected according to Figure 3. A decaying residual voltage acts again with lagging phase position in the stator during the switching interval.