Voltage – Speed Curve

• we can use a strobe to set the speed of an unloaded motor
• we can then relate the speed to the voltage and current
• we notice a linear relationship between voltage and speed

Torque Current Curve

• we can place a motor in a cradle that allows it to turn with low friction
• we can then use a lever arm to get gravity to place a torque on the motor
• that torque is balanced by the torque the motor creates to push against the air
• we can plot a linear relationship between the torque and the current

Fan Law

• we can use the strobe to set the speed of a computer fan
• we can measure the current and voltage to maintain that speed
• we can use the electrical power as an estimate of the mechanical power
• we can plot the power against the speed of the fan

Fan Duct Restriction

• we can simulate a small or blocked duct with a custom flange
• we can use an anemometer to estimate the air speed
• we can estimate the air flow my multiplying the air speed in feet per minute by the opening area in square feet
• we can then see how the watts per CFM vary with air speed