Darren, I'm not questioning wheather or not your 18 vlt motor is running at 24vlts but I do know that Underwriters requires that an item must meet stated performance within +-5% (not +-5vlts) of its rated voltage. That would mean that you could safely apply 18.9 vlt D/C to your 18 vlt motor without shortening its life. Referencing that your more was rated at 18 vlts, I checked the motor on my Flexilite and Imperial units and both were listed at 12 vlts and would probly FRY in short order if 24 vlts were applied. Furthermore, you can run a 24 vlt motor at 12 vlts with decreased performance but you can't apply 24 vlts to a 12 vlt unit without causing damage. Maybe you are running your unit at 24 vlts but I wouldn't recommend that anyone else try it unless they are fully aware of the possible damage that may occure.

Darren, I disagree. I checked the voltage rating on my two electric fans (Flexalite & Imperial) and they're rated at 12 vlt D/C. I'm not contesting that your fan is rated at 18 vlts but Underwriters Lab. requires that a device meet it's stated performance at +-5% at its rated voltage not +- 5 volts (5 volts is close to 30% of your 18 vlt motor). This means that you could supply a max of 18.9 volts w/o exceeding its safe operating boundries. I dont believe that any 12 vlt electric fan can be run on 24 volts without drastically shortening it's life or SMOKING it. Yes, I know that the electrical system is closer to 14 vlts D/C but 14 is a lot less than 24.