Hi,
We have a variety of motors in our lab, all similar to 3074: Pololu - 75:1 Micro Metal Gearmotor HPCB 6V with Extended Motor Shaft. However, it seems that over time we’ve acquired a variety of gear ratios and voltages of motors in the lab as they all behave differently. Is there any way to visually tell the difference so we can label the motors because we don’t see any sort of marking or number on any of them to tell us what kind each is? If not, what’s the best way to distinguish the motors from each other.
Thanks,
Adam Hinson
Hello, Adam.
If you are using our Micro Metal Gearmotors, the motors should be stamped with some markings that we can use to help narrow down the voltage and power level. Unfortunately, the gearbox is harder to identify. Generally, the easiest way to identify the gear ratio once you know the voltage and power level is to get a measurement of its free-run speed and comparing that to our specifications for reach gear ratio. A tachometer or encoder can be used to get this measurement, but if you do not have either, you can run it at a lower voltage and extrapolate up. You can find more information about this process in this post by Patrick.
Brandon
Hi Brandon,
Unfortunately, it seems like our motors don’t have any markings on them. A few of them have red markings on them but most of them are without markings. Is there another marking I should be looking for that I’m missing.
Thanks,
Adam Hinson
All of our Micro Metal Gearmotors should have markings inked on the side; unfortunately, they do not have any additional identifying markings. Are you sure all of the motors are from us (they are a common form factor)? If so, it is possible that they unfortunately wore off.
You might be able to narrow it down by looking at the motor terminals to distinguish between the HPCB versions with carbon brushes and the others with precious metal brushes:
The one on the left has carbon brushes the one on the right has precious metal brushes.
Lastly, you could try measuring the resistance between the terminals and comparing it to the specifications on our product pages (e.g. a 6V motor 1.5A stall current should have a resistance of around 4Ω). However, it might be difficult to get an accurate measurement of low resistances. If you have access to something that can do a four point measurement, that would be ideal.
Brandon
