Reduction question(again)

[Espeefan]

Originally Posted by Dean

I've been looking at some motors,but none of
The manufacturers give the watt output,how can
You know?

Some manufacturers give this information, and some don't. It's often times more difficult to find this information for brushed motors than brushless. Usually because brushless motor power consumption is often times more important for sizing battery packs, and figuring out run-times. RC aircraft modelers always want to maximize their flight time, and brushless is so common place with those models, the specs are usually published.

If you do happen to know a specific motor's current consumption and you know the voltage it is running on, use this formula.

wattage = voltage * current

By the way, 1 horsepower = 745 watts.

As far as motor torque is concerned, the rule of thumb is brushed motors with more turns will produce more torque, but there are other variables to consider too. Hand wound vs. machine wound - it definitely makes a difference. In mass production, machine wound rotors can't match a hand wound rotor. The difference is the wire is wrapped more tightly, when done by hand, and more uniformly. The tighter and more uniform the armature wraps are, the stronger the magnetic field will be, when the current flows. Other things that have an effect on magnetic field strength include wire size, as well as the type of brushes used. So there can actually be more to a motor's performance, than just the number of turns.