Motor Voltage

Project Number: 25

Description: Modify the preceding circuit into this one. Set the meter (M6) to the 5V setting and place the wind fan on the motor (M4). Push and release the press switch (S2) and watch the voltage on the meter as the motor speeds up and slows down. Without pressing the switch, spin the fan clockwise with your finger and watch the voltage. In the preceding project, the current dropped as the fan sped up - now you see why. The spinning fan produces a voltage in the motor; this voltage opposes the voltage from the battery, reducing the current as the motor speeds up. How will the voltage and current change if you replace the wind fan with the water wheel? Try it.

Snappy: Electricity is generated when you spin the motor shaft. A coil of wire is on the shaft, and as it spins past the permanent magnet an electric current is created in the wire.