How does the resistor control the blower speed?

Answer 1

By decreasing the flow of electricity to a motor, and thereby cutting the amount of power that can be dissipated to move the air.

Answer 2

The resistor resists the flow of current, reducing the amount of current which gets to the blower motor. For a variable resistor control, there is a contact which touches the resistor. When you move the contact over the resistor, you increase of decrease the amount of resistor, and thus the amount of resistance, through which the voltage must push the current. When there is less of the resistor in the circuit, more current will flow.

Answer 3

Picture an electrical circuit as a plumbing problem. Instead of a wire carrying electricity, you have a garden hose transferring water to a mechanical sprinkler that sweeps back and forth over the lawn. Stepping on the hose, kinking it, or otherwise constricting the diameter somehow will reduce the flow of water though it and thus causes the sprinkler to slow down. In reality a resistor is composed of material that does not allow for the movement of electrons through it as easily as it moves though the wire. Since there is less current (movement of electrons) though the wire, the blower will slow down.

Answer 4

The nature of the resistor is to resist the current flow, if the resistance is increased in a circuit less current flows and if the resistance is decreased the current through the circuit increases.

So if a variable resistance is employed in the armature control mechanism, the armature current varies with the variation in the resistance there by the speed changes accordingly.

this is similar to what happens to the no of revolutions of a wind mill if the air flow changes.