How to obtain the parameters of DC motors?

  • Thread starter bbq_build
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  • #1
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Hello, I appreciate if somebody could help me to resolve this. I bought a geared DC motor from a store. I would like to obtain the following information: Resistance, Inductance, Back EMF constant, torque constant, and the voltage caused by Back EMF when the motor is supplied by a voltage input higher than the recommended one. What experiments do you recommend to obtain these values? Do I need fancy equipment to get these values by experiments?

Even I asked the company, they can only provide the following information (at the recommended voltage): torque constant, Back EMF constant, Dynamic Resistance and Motor Regulation. The guy asked the manufacturer. He said that these are all he can get and he has no idea what they mean. if I supply 4V higher than the recommended input voltage, will these provided values change a lot? Which parameter(s) stay the same?

Thank you
 

Answers and Replies

  • #2
Nidum
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Any identifying information on the motor - maker - product number ?
 
  • #3
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Just a Tamiya toys motor. The manufacturer does not seem to want to provide all the information.
 
  • #5
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They only give the gear ratio. I need the parameters I mentioned for modelling. Any good approach to measure the values?
 
  • #7
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Thanks but not sufficient to model it. I need the parameters mentioned in the original post.
 
  • #8
Nidum
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Well I can't really see why you need any of these values but if you want to experiment then you need to build a test bench .

There would have to be at minimum some variety of very sensitive dynamometer , a tachometer , voltage and current meters , an oscilloscope and a finely controllable power source .

Problem is that any transient events like run up time to speed are going to take place so quickly that you won't be able to take reliable readings manually .

Probably best to use a PC to control the experiment and log all the data automatically .

What do you want to use the motor for ?
 
Last edited:
  • #9
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Applying excess voltage may well result in excess current and a burnt out motor. Be a shame to burn up your motor just as you get the parameters you want.
 

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