How to Change the Speed in a DC Motor
DC Motors are used for almost any kind of application you can think of. From the tiny motor that rewinds a DVD in a DVD player to the large motors used in electric automobiles, DC Motors are useful in many applications. However, without a way of controlling how fast a DC Motor operates, it is useless as a means to perform work. A DC Motor uses direct current electricity to operate. It also uses electromagnetic fields and magnets to make the rotor (the moving part of the electrical motor) move. The speed of a DC Motor can be controlled by how many volts are applied across the electrical leads. For example, a DC Motor connected to a 6V battery will have its rotor turn approximately half the speed that the same DC Motor connected to a 12V battery will turn.
DC Motor Control Mechanism (H2)
A DC Motor Control Mechanism is used to control or change the speed in a DC Motor. In order for a DC Motor Control Mechanism to operate to its full potential, it needs to consist of the following things:
• A DC power source with three leads, V+, V-, and 0V.
• Three wires which are connected mechanically to V+, V-, and 0V.
• A potentiometer (a type of variable resistor). The potentiometer has three electrical leads: two terminal leads, and one called a “wiper” lead. The position of the “wiper” within the potentiometer determines how much resistance the potentiometer has.
• A DC Motor.
How does the DC Motor Control Mechanism work (H2)
The DC Motor Control Mechanism operates by varying the voltage applied to the leads of the DC Motor. For example, if two 6V batteries were used as the power supply, V+ would equal +6 VDC, and V- would equal -6 VDC. If the potentiometer is adjusted in such a way that the “wiper” is closer to the terminal attached to +6V, the rotor will rotate faster in one direction. As the “wiper” is moved closer to an equal distance between +6 V and -6V, the rotor will slow down, and eventually stop. As the wiper moves closer to -6V, the rotor will reverse direction, and rotate faster in that direction.
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