My little Nema 11 stepper becomes hot when I use it to hold a position. This is quite normal since it use 1.3 A of current. My plan is to use the big aluminium supporting bracket as an heat-sink too. In this way I will avoid a bulky envelope box (this stuff has to be mounted on a motorcycle).

I'm thinking to apply a layer of thermal past between the motor and the surface of the bracket before fixing it by using some screws. After googling, I discovered that there is no agreement about which pastes are electrical conductive and which are not. I got confused...

What is paste composition more suitable for my application? Somebody has some practical experience about that?

  • 1
    \$\begingroup\$ Do you need the full 1.3A to hold the position. A common approach is to reduce the current while holding using PWM. \$\endgroup\$ Dec 20, 2020 at 11:07
  • 2
    \$\begingroup\$ Any type of paste will be better than air, and paste may only give you a tiny advantage over simply mounting it dry, which is far more convenient and less messy. Try it dry first. If it's good enough, you're done. If not, then try some paste. Whether electrically conductive or not should not make any difference when mounting a grounded motor chassis to a ground mounting bracket. \$\endgroup\$
    – Neil_UK
    Dec 20, 2020 at 11:45
  • \$\begingroup\$ @KevinWhite: thanks for the trick! I will try it in the next days. This could help to reduce the heat and (maybe) the need for an heat-sink. \$\endgroup\$
    – gimpo
    Dec 21, 2020 at 16:59
  • \$\begingroup\$ @Neil_UK: seems that I need to but one of that IR devices to measure temperature and make some tests. The big problem is how to explain that to my wife... \$\endgroup\$
    – gimpo
    Dec 21, 2020 at 17:01


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