I am not a physics guy, so not even the basic concept of a DC motor is easy for
ID: 1373454 • Letter: I
Question
I am not a physics guy, so not even the basic concept of a DC motor is easy for me. My question is as follows:
How do these parts of a motor affect its RPM and Torque?
I had my research a while ago so I filled out some of it; please correct if there is something wrong.
More turns - less RPM, more torque, less battery consumption
Less turns - more RPM, less torque, more battery consumption
More winds (number of wires) - less RPM, more torque, ?
Less winds (number of wires) - more RPM, less torque, ?
Thicker wire - ?, ?, ?
Thinner wire - ?, ?, ?
Stronger magnets - less RPM, more torque, ?
Weaker magnets - more RPM, less torque, ?
Bigger commutator - ?, ?, ?
Smaller commutator - ?, ?, ?
Also, if you know any tutorials for a guy who has the brain of a six-year old boy regarding a DC motor, please let me know. Thanks and apologies for my English!
Explanation / Answer
The RPM is restricted by frictional losses in the engine and the tendancy of the engine to explode if you rotate it too fast. In that sense the RPM limit is down to how well the engine is made and what it's made of rather than any fundamental EM properties.
The torque is dependant on how large a magnet field the engine generates, and this is mostly dependant on the current it draws and the number of turns in the coil. So the thickness of the wire has no effect except if it affects the resistance and therefore the current drawn. Likewise the commutator won't have any effect.
Have you had a look at http://en.wikipedia.org/wiki/Electric_motor#Performance. This gives a pretty thorough description and isn't too technical.
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