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Should I build this for quick drag strip, making this simpler and cheap, or go full ev?

  • Keep it Simple and Cheap, for drag strip only!

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Industrial DC shunt motor EV project

594 Views 3 Replies 2 Participants Last post by  piotrsko
This is something I thought to do to make use of an aged motor once more.

I may be able to pour money in as i go, might also eventually have support from family business, advertising purposes.

I would like to create a one of a kind heavy DC electric vehicle, using what i have on hand.

I understand too little about circuitry and code workings to do this alone, but Ive found multiple works online that have helped enlighten me a little, like using dual IGBTs in a H-bridge circuit along with current sensors and dsPICxxxx controllers to be able to take variable dc input voltage within a set range and then convert to a variable dc output voltage within a set range based on analog input(from an accelerator pedal). (No clue how to wire or code this)
Optimally, this should also be able to work in reverse to charge battery when braking/slowing with idle.

I have an old industrial DC shunt motor (pic below), and an available chassis with suspension installed already(will figure out mounting later and gears/differential).
Rectangle Gas Font Wood Fixture


I have no idea how much range id want, or even be able to get out of this theoretical ev, perhaps 50 miles to start?
For those with a good guess on how far i could get, heres the proposed battery pack setup i thought up to work off of:
Pack idea 1:
A 100 series 30 parallel pack (3000 count) of 21700 samsung 50E cells totalling approx 50kWh/144Ah at a range of 250V-420V with a max safe amps draw of 150.
Not sure if i want to go with protected cells, or use bms systems...

Also thought up a much cheaper, and lightweight pack for short drag strip use:
Pack idea 2:
A 58 series 6 parallel pack (348 count) of 21700 samsung 40T cells totalling aprox 5kWh/24Ah at a range of 145V-243V with a max safe amps draw of 210.
I figured if i go with this build, i wouldnt need to worry about motor drawing too many amps, since it would only be used for a short moment at proper voltage anyways, and with lighter weight car build overall, load might not force higher than rated amps on motor.
Additionally, I could possibly get away with directly powering motor, with no controller besides what is essentially a go button.

So what i need is a working circuit and code build that would suit the specs for the regulator/controller, and for both builds; a charger device for standard 120v or 240v ac wall outlet.
I can provide additional photos if needed, like wires from motor like control leads.

Thanks for reading this wall of text, and hopefully ive provided enough details for anyone interested in figuring this out.
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Shunt windings are generally powered separately either for control, regen, or reverse.

DC brushed controllers basically switch on and off utilizing a DC time constant through reactance to regulate the apparent voltages. In other words it switches so fast the voltage only rises somewhat before it's shut off again. With your "GO" button concept, you get 100% power every time aka bad juju.

Wound motors take a bit of time to get hot, which is where most of the damage occurs by melting the insulation or in some cases by spinning so fast, centrifugal forces cause it to come apart.
 

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Discussion Starter · #3 ·
Shunt windings are generally powered separately either for control, regen, or reverse.

DC brushed controllers basically switch on and off utilizing a DC time constant through reactance to regulate the apparent voltages. In other words it switches so fast the voltage only rises somewhat before it's shut off again. With your "GO" button concept, you get 100% power every time aka bad juju.

Wound motors take a bit of time to get hot, which is where most of the damage occurs by melting the insulation or in some cases by spinning so fast, centrifugal forces cause it to come apart.
So with the drag setup, it would be good to have at least a one-way controller instead of a stop/go full power approach, for safety.
Is that about right?
Also, this motor has separate amature and field leads, along with (temperature?) monitor leads, and a smaller lead that the diagram on the device calls a control lead that has (4?) small wires inside of different colors.
 

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The controller only affects what power goes and how much of it you get.

Field windings are sometimes seperate from armature windings for direction reversal. A 2 post GE wont reverse, whereas a seperate excited field will, otherwise your transmission needs a reverse gear.

Drag race much? There's been days I never got to full throttle because the track conditions sucked and you couldn't get tires to stick, a quarter mile of squirrelly ain't fun even at 14.03 ET.

Motor temps are good to have, the 4 wire thingies I have no clue
 
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