You're going to need a motor. Or two. Or maybe 3 or 4.

There are a variety of Motor options you can consider to build a power racer.

By far, the most common motor in the league in the 2020s is the BOMA MY1020 “Silver Can” type motor. this motor is sold with a variety of stickers/ratings, some of which are particularly different than others.

Be aware of the following when you are looking for one: 'Can' motors in this same general MY1020 package are sold both Brushed and Brushless. It's exceedingly rare to find a kart that runs a Brushed motor anymore, so you'll likely want to stick to a Brushless type for all new builds. Even within the Brushless distinction, they come with a variety of nominal voltage ratings and overall power ratings. Typically, motors in the “48V” “2000W” or “2kW” sticker is generally appropriate for Racing, and are often cheaper than the “72V” “3000W” “3kW” stickered versions. (Someone who is better at motors than I may chime in here with actual material differences between these.)

If you select this or any type of Brushless Motor, you'll need some sort of Brushless Motor Controller as well.

• MY1020 Electric Scooter Motor (48VDC 1500W) For a typical builder looking to get into the race

if you've got some electrical prowess under your belt already, you may be able to engineer an alternator out of a standard combustion engine type car (or truck, firetruck, ambulance, etc) to operate as if it was designed as a Brushless DC motor. Here's the general scoop:

• Pick an alternator and identify and cut out the “Diode Pack”. This is the collection of Diodes (in a Wye or Delta configuration) that the automobile uses to rectify the immedeate output of the alternator into roughly 12vdc to recharge the 12v Lead-Acid when it's installed in the car.
• rewire the remaining stubs of magnet wire that come out of the coils of the alternator (the stubs of wire that you just freed from the now-discarded diode pack) into either a Wye or Delta configuration. Your choice of Wye or Delta may be partially determined by the internal configuration of the particular Alternator you've selected, or you may have the opportunity to make the determination yourself. Do note: the Wye/Delta configuration you select will affect the speed/torque curve of the motor you will end up with. Think about that when you go to design the rest of the power train.
• Connect (solder? crimp? your choice) the now-configured stubs of magnet wire into leads which will connect to the BLDC motor controller you use to drive the alternator. (Keep your Wire Gauge in mind so these don't get too toasty – 10AWG or bigger is recommended, 12AWG is likely permissible.)
• Then turn your attention to the Commutator of the Alternator. this is the part of the alternator that spins, and it has it's own coil of magnet wire which, in it's original installation, is energized from the 12V battery to create magnetic flux in the outside windings. This is the principle that the alternator uses to generate 12V on the outside windings. Identify the electrical connection points on the alternator which pass current through the brushes and into the coil on the commutator. this coil of magnet wire will be called the Field Coil for the rest of this guide.
• Connect (solder? crimp? your choice) electrical leads to the Field Coil connectors on the alternator. you'll connect these leads to a power supply to provide current to the Field Coil so that it acts like a magnet (the equivalent of the permanent rare earth magnet on the rotor of a traditional BLDC motor)

If you select this or any type of Brushless Motor, you'll need some sort of Brushless Motor Controller as well.

There are additional considerations for when you wire up the alternator, on top of just “pick a BLDC controller”:

• The BLDC controller you use will need to either support “Sensorless” mode, since Alternators do not contain Hall Sensors for motor positioning, or you'll need to install hall sensors in the body of your alternator, or install some other sort of position sensor that the controller you select supports.
• The Field Coil of the alternator may burn out (magnet wire insulation could burn through and render the alternator useless) if you run too much power through it. You can engineer against this by driving the Field Coil with an adjustable CC/CV supply, by driving it with a Brushed DC controller, by slapping a current-limiting Resistor on it (less recommended) or any other method if it works for you.
• be aware that the current run through the Field Coil will essentially all just be “burned off as heat” so you may choose to put the wiring for it on a switch so you can manually energize or deenergize it as you see fit.
• Further, since all of the magnetic components of the Alternator-Motor are electromagnets, you can purposefully vary the electrical characteristics of the coils to achieve a varied/specific torque-curve. generally, you'll want the Field Coil to be Saturated or near-saturated when the kart is taking off from 0, but you need far less energy to keep a kart going in a straight line at 15-20mph. You could then, reduce the current through the field coil to “trade off” some of your unnecessary torque for more top-speed. if this functionality was automatically controlled, you could, for example, wire it up to a “Turbo Boost” button on your dashboard.

The hub motors out of commercially produced “hoverboard” type electric vehicles can be rated to accept the kind of voltage and power typically used in Power Racing. Karts [who?] have been made which have one hoverboard wheel/hub motor on each, so that all four wheels are powered wheels. each hub-motor is driven by its own ~500w BLDC controller. the overall cost of two broken hoverboards and four 500w BLDC controllers can be nearly comparable to one 1500/2000W BLDC controller and BOMA/MY1020 motor, and the remaining savings can be made up in not having to include a drive-train.

Karts [who?] have been made to run on “Melon” type Outrunner motors. these BLDC motors are often controller with a BLDC Motor controller called an ESC (Electronic Speed Controller). Outrunner/ESC combination motors take up a smaller package size (very useful in a kart as small as a Power Racer) but are often more expensive, which makes engineering them into your Bill of Materials (BOM) a greater challenge. It's generally discouraged against for first-time builders unless you have experience with them already.

• Turnigy AquaStar T20 3T 730KV/1280KV Water Cooled Brushless

If you are designing a 3-wheel kart (either front or rear) you may choose to include a Hub-motor with an axle that extends all the way through to both sides of the wheel, as the powered hub motor wheel can be supported on both sides (like with a yoke) according to the Rules only if it's on a 3-wheel kart. (since, generally, wheels may not be protected by the chassis or bumper on their outside) Some karts [who?] have operated both with the Hub Motor being the only powered wheel in their setup, and with the Hub Motor being powered in conjunction with a traditional chain/sprocket drive-train on the other axle.

• Golden Motors - Hub Motor Model MBG36F The motor used on the Bluth Family Stair Car. Probably not a recommended motor, but we did it, and it mostly worked.

All About Ratings:

• Stall Torque
• Voltage
• RPM (max RPM)
• Power (Watts)
• Temperature/Cooling
• Drive Gears and Sprockets