Jake Anderson wrote:

>>> MC34063 + FET + Schottky + Coil + very few passives + something to 
>>> mount it on + not much else.
>>>
>>> Although, at the 500 Watt power level, what are you wanting to do that 
>>> won't justify > $US10?
>> 
>> A motor. The problem is the oomph per price; currently we're using a 36
>> Nm peak motor (40 A peak, 100 rpm no-load max) that costs ~25 USD.
>> We're working mostly on the far end of the typical motor curve, which
>> is not good. But I haven't yet found another one with a higher gearing
>> in the same price range. So either expanding my options into the 24 V
>> range could help with finding a better suited motor, or boosting the 12
>> V supply and drive it current-controlled to compensate for the voltage
>> losses in the MOSFETs and connections would also improve things. 
>> 
> Is this a geared motor? I am slowly plodding towards making something
> with similar specs as a brushless motor.

Yes, that's brush DC motor with a worm gear; seems to be the least
expensive construction. Or at least the only one I found that seems to be
produced in high enough numbers to be cheap enough :)

One thing I'm missing is reading the speed of the motor before the gear;
that would improve the controller quite a bit. 

Gerhard

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