Originally Posted by STL_Lucas
How can I tell if a fan is ac or dc? I'm guessing this is the problem since both power supplies aren't working strong enough and I know the 2nd one ran two other fans I've had.
It is DC.
1. It's a computer case fan, and they are all DC since everything in a PC except for the power supply itself runs on DC. AC fans are common for all types of enclosures and other uses, but never for PC use.
2. It should tell you on the fan itself on the sticker on the back of the motor housing.
3. If it was an AC fan it would not run at all when hooked up to your DC power supply.
Do you have any other fans in a computer you could borrow for a test? Are you anywhere near Edmond OK?