# What are some things I could test for with this motor for a physics depth study? (1 Viewer)

#### CrayV

##### New Member
Hey all,

For an experimental report / depth study (with the theme of 'Analyse electric and magnetic interactions due to charged particles, currents, and/or fields.'), I would like to make an experiment that involves the motor with a gear box as seen in the attatcehd image (Single Motor 4 Speed Gearbox / Axle Assembly on Jaycar). Does anyone know of anything I could experimentally test with this motor? I was thinking of measuring the torque of the motor through a force meter, but can anyone think of anything else?

Any and all help is greatly appreciated.

#### wizzkids

##### Active Member
I think you will find that is a reduction gearbox, and the output speed from the gearbox is extremely low. Conversely, the output torque will be extremely high. The inner workings of the motor are concealed, so you can't really change any variables about the motor.
That Tamiya product looks like it is intended for servo-motor controls.
However, if you really want to use Tamiya motor/gearbox combination, then you could replace those crank arms with a cotton reel to turn it into a pulley. Then wrap a string around the pulley (the cotton reel) and attach it to a known mass (let's say 500 grams). Turn on DC current to the motor and measure the time to raise the 500g mass through 1 metre. You have done work against the gravitational field equal to W = mgΔh, and mechanical power W/t = mgΔh/t. Then measure the DC electrical power input to the motor, from this relation: P = V x I and you can calculate the efficiency of converting electrical energy into mechanical work. You would need to gather some equipment - a stopwatch, a metre rule, an electrical multimeter to complete this experiment. You also need to identify the friction losses in the gearbox (which is hard to quantify, but not impossible).
That's about all I can think of.
Not really enough to constitute a proper depth study.
Anyone else?

#### CrayV

##### New Member
I think you will find that is a reduction gearbox, and the output speed from the gearbox is extremely low. Conversely, the output torque will be extremely high. The inner workings of the motor are concealed, so you can't really change any variables about the motor.
That Tamiya product looks like it is intended for servo-motor controls.
However, if you really want to use Tamiya motor/gearbox combination, then you could replace those crank arms with a cotton reel to turn it into a pulley. Then wrap a string around the pulley (the cotton reel) and attach it to a known mass (let's say 500 grams). Turn on DC current to the motor and measure the time to raise the 500g mass through 1 metre. You have done work against the gravitational field equal to W = mgΔh, and mechanical power W/t = mgΔh/t. Then measure the DC electrical power input to the motor, from this relation: P = V x I and you can calculate the efficiency of converting electrical energy into mechanical work. You would need to gather some equipment - a stopwatch, a metre rule, an electrical multimeter to complete this experiment. You also need to identify the friction losses in the gearbox (which is hard to quantify, but not impossible).
That's about all I can think of.
Not really enough to constitute a proper depth study.
Anyone else?
Ok, thanks so much. I am thinking of instead building my own motor, as opposed to just buying a motor and getting measurements. I could certainly use your idea, and I was also thinking of measuring torque and rotational speed. Do you know of an effective way to measure these two things? Are there any other things I could measure with my own built motor? I appreciate the help

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#### wizzkids

##### Active Member
If you are considering building your own motor, then you might like to watch my Physics video on the motor effect: