any low-speed gearless hub motor?

[NoRegrets]

I have a 24V 250W mini-hub motor that I am currently using as a pedal generator.  It performs well but the gear train makes it a little noisy.

Does Golden Motor (or anyone else) might make a brushless AND gearless bicycle hub motor that would produce about 15V at low (~250 RPM).  Thanks.

[Bikemad]

Click the tab on the GM site for further details.

I would say that the 36V 500W HBS36R Rear Hub Motor should be suitable for your needs, but you will need a rectifier and a suitable voltage regulator to limit the maximum voltage.

You might also want to take a look at this post.

If it's going to be used without a rim, I would suggest fitting some sort of flywheel to give a more even speed for pedalling, otherwise it could slow up too much at the end of each pedal stroke, making it very difficult to pedal.

Alan
 

[Perbear]

I have seen a geared rear hub motor with helical gears on the motor. The three planet gears (plastic) consists of two gears. One that fits the helical gear on the motor spindle, and a regular spur gear that fits the internal  sprocket ring gear. This construction is very silent. It is not possible to hear noise from the gears while riding the bike. I do not know who makes the motor but it is larger and probably heavier than the GM minimotor.

[ccbreder]

Alen has the right idea. Perbear is referring to Heinzman. They are hard to find in the US. Gears just add to the resistance on a generator.

[Perbear]

Alen has the right idea. Perbear is referring to Heinzman. They are hard to find in the US. Gears just add to the resistance on a generator.

No, the motor I saw was definitely not Heinzmann. They use a brushed motor with a fixed gear: https://endless-sphere.com/forums/viewtopic.php?f=2&t=4190

The motor I saw (and partially disassembled) had planetary gearing. A typical planetary gearing has energy loss of 3% but to find the exact efficiency you need to do a calculation like this: http://www.roymech.co.uk/Useful_Tables/Drive/Gear_Efficiency.html

[ccbreder]

https://endless-sphere.com/forums/viewtopic.php?f=3&t=4892