That is true and is the approach taken in most electric screwdrivers, but that does not seem to be the case with the ARCO. Notice you don't get the same speed change between load/no load operation.renatoa wrote:Yes, the specs seems right for a DC motor followed by a planetary gearbox, 40-60 ratio is quite common.
A similar solution solution is used by a Turkish company to drive Commandante grinder, 24V DC, 1:100 reductor, check here:
The gearbox ratio seems more than double than Arco, but also RPM is less than half, 80 to 96.
My guess about the pulley... it is 1:1, not involved in reduction, used just to obtain a more compact shape of the whole assembly.
A 1:1 pulley with a planetary gearbox would be interesting, indeed the reduction could be achieved for high ratios, but I'm not sure if combining that with a belt drive would be great for reliability.