motor load test

Discussion in 'General Electronics Chat' started by metlab123, Dec 13, 2015.

  1. metlab123

    Thread Starter New Member

    Dec 13, 2015
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    we need to test the quality of small bearings through motor load test.
    For that we made an apparatus with a small DC motor of 24V & 1Amp. capacity.
    can i measure milliamps through digital multimeter (with data logging).
    Pls. suggest the proper method and measuring instruments.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    What characteristics of the bearings are you wishing to measure?
    Max.
     
  3. hp1729

    Well-Known Member

    Nov 23, 2015
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    How much the bearing loads down the motor relative to ... ?? some other bearing??? by measuring motor current. Yes, it would give a relative value, but how do you give meaning? You could say one bearing has less drag than another.
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,547
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    I would think a simple current meter measurement, using standard off the shelf bearings and you could include sintered bronze sleeve bearings for a comparison to a ball bearing.
    No load and maximum load could be included in the test across the full rpm range, in the end it is just a comparative test, unless you have some qualified data to compare it to.
    Max.
     
  5. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    A common way is to use a current-sense resistor (e.g. 10 milliOhms) to convert current to a small voltage, then use an opamp to bring the voltage up to something in the 0-5V range suitable to feed an ADC input of a microcontroller which logs data to an SD card.
     
  6. hp1729

    Well-Known Member

    Nov 23, 2015
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    I think the problem is making the current value into some "drag" value. Is a relative comparison all we can make?
     
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