Re: [VAC] Installing Fan-tastic Fans

["Dr. Gerald N. Johnson" <geraldj@xxxxxxxx>]

A fan motor has to be made special to run on both DC and AC or supplied
with a rectifier. The modern permanent magnet field DC motor that has
good speed regulation won't like AC.

The only appropriate motor without a rectifier would be a series wound
universal motor and I don't see any in Granger (1996) for 12 volts.

A diode bridge rectifier (available at Radio Shack, pick one with 10 or
25 amp rating) can make the permanent magnet motor tolerate AC. Wire the
motor leads to the + and - terminals (requires the motor winding not be
grounded internally) and the supply to the ~ terminals.

Far better for a long term solution to replace the univolt with a good
DC battery charger and run everything on DC all the time. Statpower
makes some good ones.

Gerald J.