I'm looking for a complete electric kit/parts for a small cart with a speed limit of 5-6 km/h. Preferably with a belt drive, 12/24V, thumb switch and a dead-man switch. Maximum total weight 30-40 kg. The problem sees to be to get the speed down/ gearing it down.
I've also have a rather odd construction request: the motor drives a closed loop belt attached to a small wheel( like a skateboard wheel, but with a rubbery surface) and the small wheel drives the cart wheel by pressing down on the tire.
We should be able to supply all of the parts from the motor to the battery pack, however, we do not have friction drive rollers so that part of the project would need to be sourced elsewhere or custom made.
We do not carry any gear motors with belt cogs. We can special order gear motors with belt cogs for 1/2" V-belts if you would want to use such a large belt for your design.
Please let us know if you have any questions.
I was thinking of just using a 15 tooth belt cog on the motor and a 60-80 belt cog on the friction roller with a closed loop belt between the cogs.
When using your calc:
Motor sprocket 15 teeth
Wheel sprocket 60 teeth
Wheel dia 12.5 inch
I get a top speed of more the 23 MPH, way to fast for me. How can I get this down?
As a security feature I want to limit the speed to max 6 km/h mostly on plain asfalt and with a max weight of 30-40 kg and a drive time of 30-60 min.
Could you please if possible give me a part list that I can source at your shop?
Dead man switch(preferably with a line, like you have on a outboard motor)
15 teeth belt cog for the motor
60-80 teeth cog with 8 mm center hole for the shaft of the friction roller(with 4-6 holes for bolt on if possible)
And please anything I would need that's not listed by me.
A gear motor with 420 RPM shaft output speed would be needed to get the speed down to 6 km/h. Timing belts are not commonly used with gear motors so belt cogs are not available for them and would need to be custom made or modified from existing belt cog stock. You would need to determine how much torque would be transferred through the timing belt and choose the belt size and cogs accordingly. Switching over to chain drive would be much easier and the gear motors already make some gear noise so the chain noise would probably not be perceivable.
Regarding the motor and battery pack size, how much weight will the cart need to be designed to carry, and will it be designed for flat ground only or will it need to go up inclines?
The weight would be 30-40 kg and mainly falt terrain on asphalt.
I would like to stay away from chain-drive, but a geared drive could work if I can attach the friction roller directly on the motor-shaft. What diameter and length are available for the motor-shaft?
Would there be an option to electronic limit the RPM on a motor without gear, but still keep the torque
We have dimension drawings of all of our motors located under their descriptions. Not all of the motor drawings show shaft dimensions, however, they will give you a good idea of the shaft sizes and lengths. The 250 and 350 Watt gear motor shafts are 11mm OD where the sprocket mounts and around 12mm long.
The RPM of a motor could be electronically limited and the motor will have good torque at low RPM, however, it will not have good horsepower at low RPM so it will not produce very much power. Motors designed for higher RPMs that are run under load at low RPM also tend to overheat. So for a low RPM motor shaft speed, it is best to use a gear motor or a standard motor that runs at low RPMs which are large and heavy.