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.

 

What characteristics of the bearings are you wishing to measure?
Max.

 

What characteristics of the bearings are you wishing to measure?
Max.

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.

 

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.

 

can i measure milliamps through digital multimeter (with data logging).

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.

 

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.

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