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I need help building an electric go kart steering, gearshift, and brake mechanisms.

I am building an electric go kart, and I have a few questions.
one, if I use this turning mechanism, which wheels/axles do I use, and how do I connect the wheels to the front axle?
two, how do I connect the axles to the kart (made of wood) so that the axles spin?
three, how do I put brakes?
four, If I connect the motor to the back wheels with a chain, how do I put a gearshift? (like on a bicycle)
Thanks in advance!

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rickharris4 years ago
Did you do much research?

https://www.instructables.com/id/Building-an-electric-racing-car/

Shows how a bunch of my school kids built an electric racing car - The total cost was around $2000 most of this being the motor and battery set.

gizzmotronics (author)  rickharris4 years ago
Thank you, that had a lot of info. It seems they didn't use axles. won't the kart turn to one side if only the rear left wheel is powered?
I wrote the instructable - No as it says in the text and comments driving a single wheel makes little to no difference that is noticeable to the user.

Your steering mechanism will work OK BUT you can make it just as well

You might find this informative as well

http://www.thenorwoodhome.com/2008/09/building-an-mg-tc-pedal-car-introduction/
gizzmotronics (author)  rickharris4 years ago
If I use this motor, will three of these batteries be able to power it? The motor says 450W but three batteries can only supply 144W/battery so 432W (im probably wrong)
There are many ways of quoting the power of a motor. ideally you are looking for a CONTINUOUS rating - in general these motors are going to be chunky, heavy and solidly built.

I am pretty certain by looking at the construction the motor you show isn't 450 watts continuously rated. Perhaps 100 watts (a guess) the manufacturers data sheet would help.

The motor should work with suitable gearing but I wouldn't expect startling speed or acceleration.

This motor at 24 volts 450 watts is going to pull 18.75 amps out of the battery

You will need 2 batteries at least to get 24 volts and at 12A/hr they are going to give you perhaps 20 mins at 18.75 amps because you never get 100% of the energy in a lead acid battery out..

You need a deep cycle heavy duty battery set up - At least 70 A/hr to work a go kart reasonably well and they WILL take 14 hours to re charge.

I would start by getting the mechanical build done and then consider the electrics. Many successful drive systems have come from old washing machined which used to have 24 volt DC motors in them.

An old car DYNAMO will also work. But NOT an alternator.

I suggest strongly you read this PDF file

http://www.greenpower.co.uk/sites/default/files/library/Greenpower%20Handbook%202012.pdf
gizzmotronics (author)  rickharris4 years ago
the specs of the motor are there if you scroll down. It seems to be geared down for added torque, but the max current at 24v is 25A. It also supports 36V at 15A. Would that work?
The battery pack will drive the motor - Assuming you rig it for the correct voltage.

The only real question is for how long and what sort of performance are you aiming for.

Overall this motor isn't producing a lot of torque.
gizzmotronics (author)  rickharris4 years ago
How much torque is needed to drive the fully loaded kart (140 pounds) up a medium grade hill? Do you have any suggestions for motors?
Your question has too many variables to give a realistic answer.

HOWEVER

Please read the Greenpower PDF file I link to above.

From that PDF -
Weight of Driver 54kg
Weight of Batteries 21kg
Weight of Chassis and Motor 50kg
Total Weight 125kg

GEARING CALCULATIONS
Circumference of Tyre = Tyre Diameter x π
Wheel Speed = Motor Speed x Teeth on Motor Sprocket
Teeth on Wheel Sprocket
Wheel Speed x Tyre Circumference = Distance travelled per minute
Multiply by 60 and divide by 5280 to get Miles per Hour
Example for 16”wheel, 14T drive sprocket, 50T wheel sprocket.
Circumference = 410mm x 3.143 = 1.289m = 4.229ft
Wheel Speed = 1850rpm x 14 = 518 rpm
50
(Motor 1850rpm approx equals 15 Amps)
518 X 4.229 = 2190.6 ft/min X 60 = 131437 ft/hr ÷ 5280 = 24.9 mph

The graph shows the performance figures for their 250 watt continuous rate motor.

It is explained in the PDF - The peak torque is around 7.5 N HOWEVER these cars expect to run on the flat and performance drops significantly if there is any sort of a grade.

You will need a MUCH bigger motor to run up and doen hills at any speed or for any amount of time.

PLEASE read the stuff I linked to carefully it will save both of us a lot of time.

motor.JPG
A typo on the torque should read around 10.5 N - sorry typing too fast
gizzmotronics (author)  rickharris4 years ago
Read the pdf. Lots of useful info. One last question, which motor did you use and with which gear ratio? Thanks a lot.
It is made by this company

http://www.fracmo.com/

especially for the contest.

You can buy them from Greenpower.co.uk for £170

http://gpshop.theuniprogroup.com/index.php/motor.html
motor.JPG
iceng4 years ago
Look at this step bottom left of the picture for your first answer...

A
gizzmotronics (author)  iceng4 years ago
Thanks! Do you know any way I can build this with an axle that spins with the wheels? (This is the first time i've built anything like this)
You need two pillow blocks..
Most wheels have bearings,
I have the same problem of attaching even one wheel to a shaft.
My solution was to replace the bearing with another tube and drill a cotter
pin hole...