
Friction Losses in DC Motors by Size
Hard
How much energy does a spinning motor lose to friction alone? Every DC motor wastes some power fighting internal friction. Larger motors have bigger moving parts, which may mean more friction.
You run four DC servomotors with no load. Their power ratings range from 30 watts to 100 watts. You measure the voltage and current going in. Then you switch off the power and time how long the motor takes to stop.
From the input power and stopping time, you calculate the friction loss. Bigger motors lose more energy to friction.
Hypothesis
The hypothesis is that friction loss in a DC motor will increase as the power and size of the motor is increased.
Method & Materials
You will select four different ratings of DC motors from the same series and manufacturer. You will measure the input current and DC voltage at the motor input. You will calculate the power supplied to the motor and switch off the power. You will start a stopwatch and record the time needed for the motor to stop.
You will need a DC 24V, 500W power supply, a DC 24V, 30W servomotor, a DC 24V, 50W servomotor, a DC 24V, 70W servomotor, a DC 24V, 100W servomotor, a multi meter, an ammeter, and a stopwatch.
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See what’s includedResults
Our experiment showed that as the motor rating and size increases, the amount of friction power increases.
Why do this project?
This science project is interesting because it allows us to explore how the power and size of a DC motor affects the amount of energy lost due to friction.
Also Consider
Consider repeating the experiment to compare the efficiency of motors. Consider repeating the experiment using AC motors.
Full project details
Additional information and source material for this project are available below.Related videos
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