can you have too much magnet strength with a low current supply?

[stevefzr]

I'm thinking of building a motor to run on a low current supply. Obviously, I'll need a fairly mild wind, like 70t@32g to cope with the low current available. My question is, are stronger magnets always better? Given optimal gearing, is there any situation where I'll get less power by running cobalt mags instead of ceramic? The advantage of the cobalt is that it is much lighter, and I'm guessing that with a limit like 2 amps, light weight will be the major speed factor. Maybe a mild wind in a cobalt HO motor will be the ideal setup.

Steve

[Neal Stewart]

what are you building? MOST 1/24 motors pull more than that amount of amps on the lowest power. stronger magnets will require more amps to turn the armature. so yes, stronger magnets will cause the motor to pull more amps. IE SMQ's versus Mura's.
HO motors, from what i can read on an analog guage, pull, at max, about 1-1.5 amps, but normally less.

a JK falcon style motor doesnt pull very many amps either. somewhere around 4 at max (i think).

[Prof Fate]

I respectfully disagree.

For a while i was racing at an old raceway using MRC powerpacks that limited each lane to 1.5 amps! Careful assembly reduces current draw, greater efficency makes for lower current draw. Ball bearings, reducing drag in the system, reduces current draw. Diddling with the spring tension and brushes reduces brush tension, there will be an optimum point; too soft the brushes bounce-the current has to arc, too hard and there is too much drag on the arm. Stronger magnets, properly aligned and and gapped improve field efficiency and reduce draw. Cobalts ARE strong enough that, depending on the stack and can and all may oversaturate the stack and be less efficient.
On a 16d stack, you should be getting some 100 turns of 32. A properly set up motor ought to be pulling about .6 to .8 amps on 12 volts.
the new falcons are inexpensive and the brush system sucks, but they should still run under an Amp. A proper endbell, say a cut down Mura would be a big help here.

Prof.Fate