Big, Fat Electronics question for all y'all.

[footfootfoot]

It's got a 300° rotation, in practice if I pot it down more than 1/10 of a turn the fan stops spinning. I can't start the fan from lowest setting on the pot and bring it up, it's off until it hits full power. When the pot is on full power I can dial it down only about 1/10 of a turn before the fan stops. That's the point when it starts smoking.

It seems like not enough voltage is making it from the pot to the fan to get it to turn. I thought the whole point of a DC motor is that it can be variable speed by changing the voltage. If I understand correctly, the pot is reducing the voltage to the fan by increasing resistance. In this case, with the slightest rotation, it is dropping the voltage too dramatically. What I want is a gentle slope and what I've got is a precipitous cliff.

Is this not a voltage issue? Is there a difference between 10K Ohms and 10k Ohms? So the pot is creating too much resistance? I need a lower Ohm rated pot to get less resistance? I think I may be catching on, but don't tell the short bus to drive away without me yet.



I've powered the fan through the pot with both a 6V and a 12V wall wart, only the 12 gave me any adjustment at all. The 6 was either on or off.