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I am a secondary Math and Science school teacher, working in the Centre Scolaire Rive Sud in the South Shore area, Nova Scotia.
We are launching a Fab Lab in the school and have decided to work on Light Electric Vehicles. Students are discovering basics of electronics and coding with pedagogical kits based on Raspberry Pi. They use sensors to build a smart car: have it follow a line, detect and avoid obstacles, etc.
But our main project is to build a full-sized LEV!
We are looking for a wrecked ATV for the chassis, suspension, braking, and steering systems. We want to build the power drive system.
If you are interested in supporting this project, please follow this tread.
The two first questions we have are:
what motor would you use? Obviously - but let me know if I am wrong - we look for a DC motor 24, 48, or 60V; between 2kW and 4kW of power; and would like it to run from 0 to 800 RPM. Do you thing we are right? What motor would you recommend?
I need to learn more about hight power electric. I have never learned to work with this amount of amp and so I feel the need find a book/website/youtube channel to know more.
Do you have a good learning mean to recommend? Something like “hight power electricity for dummies”?
Hello GDavid, welcome to the DigiKey TechForum.
Sounds like a very interesting project, and I wish you all the luck with this.
I’m not familiar with this, so I’m unable to provide any useful information.
The nice thing about the Forum, anyone can add to this information. It is monitored by engineers, and hopefully one off them will add some useful information.
Keep us posted on your progress.
Interest in LEVs has lead to BLDC motor+controller packages in low-kW territory being available at low cost from the usual can-I-buy-a-vowel sources. As for quality, caveat emptor. Your first will almost certainly not be the last.
800 RPM is a relatively low figure for the power range; something 3-5 times that would be a more likely operating territory. Speed~voltage, Torque~current, and the I2R thing starts biting pretty hard as speeds decrease.
I’m not aware of a good “dummies” book for high-power electrical, perhaps for the same kind of reasons that I’m not aware of such pertaining to orthopedic surgery. Under the right (wrong?) conditions a person can draw an arc close to half a meter in length using sources of the sort you might encounter. Particularly in a secondary school context, it’d probably be better to get your lawyer involved before something ugly happens, rather than after.
Getting a basic handle on arc phenomena generally (mediocre starting point here) is good background, and understanding fuse ratings and what the current ratings of various items actually mean is quite important. For products like terminal blocks it might be a reasonable operating figure, for things like resistors it’s a figure that results in things hitting their maximum permitted temperature, and for some products such as FETs it can be a figure that became almost entirely theoretical as the tech improved by decimal places after the convention was established. Familiarize yourself with thermal modeling also; while you’ll likely not do work at a component level, the principles are quite relevant and transferable.
Understand your power source. Cell balancing is a universal concern regardless of chemistry, but particularly so if one’s going to adopt one of the fashionable-yet-tempramental lithium platforms.
That’s an ambitious multi-year multi team project.
Based on your self-description, it may be appropriate to scale back to something more manageable, with a lower cost, and a clear yet challenging objective. Perhaps a snow removal robot would be a better project for your team. Please see snow removal robot video at the end of this note.
A word of caution, even a “simple” blade type robot can do significant damage. It helps that such a machine doesn’t move very fast. However, there are hazards such as fingers caught in the mechanism.
The lower voltages and use of heavy lead acid batteries (ballasting to improve traction) eliminates some of the arc hazard pointed out by @rick_1976. Still, the batteries must be handled properly. Perhaps this could be one of the first learning opportunities for your students as the hazards are well known and documented. Your students could develop a set of best safety practices.
You should be able to find many online tutorials for motors in this ½ to 1 hp range. Search for information about the electronics for electric bikes and scooters. With a little more research, you should be able to discover hydraulic tutorials. Chances are you are close to a working system as a snow removal blade on the front of the pickup truck.
With regard to DigiKey, we offer a line of suitable connectors including the Anderson Powerpole series. These connectors are suitable for the 50 to 100 A currents you are likely to encounter in your snowbot.
Best Wishes,
APDahlen
P.S. Here are a few other ideas for your consideration:
