Can You Use A Starter Motor For An Electric Go Kart?
I’ve noticed that there is a lot of interest with people wanting to use an Electric Starter Motor for an Electric Go Kart conversion. A common question is can you use a starter motor for an Electric Go Kart? To answer this question, we need to understand what is an Electric Starter Motor and the various types that are available so that you can appropriately modify your Electric Stater Motor for use in your Electric Go Kart.
What is an Electric Starter Motor?
An Electric Starter Motor is an Electric Motor designed to start Internal Combustion Engines. Typically, they are designed to turn in one direction only as they have an overrunning clutch which locks the starter gear (pinion gear) in one direction and it releases it if the pinion gear is rotating in the opposite direction. This prevents the starter motor from burning out if the pinion gear fails to release itself from the ring gear of the flywheel. The starter gear (pinion gear) will engage with the ring gear of the fly wheel of the Internal Combustion Engine when activated to do so. This engaging of the flywheel by the starter motor is done via a mechanism that throws the starter gear in alignment with the flywheel. This throw out mechanism is either done by the inertia of the pinion gear as the pinion gear travels a cork screw type shaft (like in Bendix or Inertia Starter Motors) or more commonly via a solenoid that activates a lever which throws the pinion gear.
Electric Starter Motors have either permanent magnets for its source of magnetic fields or more commonly, field windings, where electro magnets are used instead of permanent magnets. If the starter motor has field windings, you then have to work out if the electric starter motor is series wound, shunt wound or a compound Electric Motor.
What Modifications Do YOU Need To Do To Make The Electric Starter Motor Suitable For An Electric Go Kart?
One of modifications you need to make to your Electric Starter Motor to ensure it can be used as a traction Electric Motor for your Electric Go Kart is to ensure that your gear, pulley or chain drive is compatible with the drive train of your go kart. Most racing go karts use a chain and sprocket set up. The chain has a specific pitch and a specific roller diameter. This means you have to have front and rear sprockets that are compatible with the chain. I found that a motorbike sprocket was not compatible with a go kart chain. I have also been informed that the chain and sprockets of racing go karts are not interchangeable with the ones found on hire karts. Since my go kart was a racing go kart, I stuck with the chain and sprockets used in racing go karts. The picture on the left shows a modified Electric Starter Motor installed in my racing go kart with drive train attached connected. I bought a front sprocket (which gets attached to the electric motor; rear sprocket gets attached to the rear axle by bolting it onto a sprocket carrier). Before I could installed the Electric Starter Motor as shown on the left, I had to make some other modifications to the starter motor. The front sprocket had to be attached to the Electric Starter Motor.
I got the front sprocket welded to the pinion gear as shown below.
The Front Sprocket that was welded to the Pinion Gear was then assembled back into the Electric Starter Motor as shown in the photo on the right. Washers were packed between the Front Sprocket and the retaining circlip to take up any space along the shaft of the Electric Motor. This prevents the pinion gear-front sprocket assembly from throwing out (where previously, the starter motor was designed to throw the pinion gear whilst starting an Internal Combustion Engine).
The next thing that needs consideration is the mounting of the modified Electric Starter Motor to the Electric Go Kart. Most likely, the Electric Starter Motor will need some brackets made up to mount it onto the Electric Go Kart. Every Electric Starter Motor will have a different mounting points. Some have mounts on the body of the starter motor, whilst most are flange mounted. With my go kart, I used angle iron as I had mount points on the body of the Electric Starter Motor. The Electric Starter Motor was bolted to one side of the angle iron. The other face of the angle iron was attached to the go kart using U-bolts (U-Clamps) so that I did not have to drill any extra holes into the go kart frame. Drilling holes into the go kart frame will probably weaken the frame. Also, as the modified Electric Starter Motor has a lot of torque, I had to reinforce the angle iron to prevent the angle iron from flexing. Prior to reinforcing the angle iron, the angle iron would flex, allowing the chain to come off.
After the modified Electric Starter Motor was mounted, all I had to do was wire up the Electric Go Kart and it was ready to drive. I’ve noticed that my Electric Go Kart on start up and acceleration, it is pulling over 300 Amps. This gives it impressive acceleration.
The major advantage of using U-Clamps (U-bolts) is that you can mount things securely to the go kart frame with minimal modification to the original go kart frame itself. This means you can restore it back to original condition at any time. Also, you don’t weaken the frame due to unnecessary drilling.
An Electric Starter Motor can be used for an Electric Go Kart with the following things taken into consideration:
- The Electric Starter Motor needs to be modified to suit the drive train and mounting of the go kart.
- They can get hot when used. This is because they are only designed to run for 10 seconds.
- You need to think about how you are going to cool the Electric Starter Motor. If they get hot, the motor burns out. I’ve experienced it.
- It can be difficult to reverse the direction if you don’t remove the over running clutch mechanism.
- If your Electric Starter Motor is a series wound motor, changing the polarity of the power applied to the Electric Starter Motor will not reverse the direction of the shaft. You can modify this if you separate the excitation windings and reverse them. With permanent magnet electric motors, changing the polarity applied to the Electric Motor is sufficient to change the rotational direction of the shaft. I believe another way to reverse the direction of a series wound motor is to use a reversing contactor, but I have not tried it myself yet, so I can’t verify it for sure yet.
- Electric Starter Motors suck up a lot of amps and can drain batteries really quickly.
Crazy Al signing out.
|Al Bunzel, also known as Crazy Al from ElectricCarConversionBlog.com has a passion for Electric Cars, Electric Vehicles and Electric Car Conversions. He has done an Electric Go Kart Conversion using an Electric Starter Motor that came from a small Industrial Kohler Gasoline Engine. You can read more about this conversion on http://electriccarconversionblog.com/electric-go-kart-story-part-1|