# Sepex versus AC15-30 sold at Thunderstruck,regen...



## mettzman (Mar 18, 2009)

Mostley curios about how regen actually feels and how much it actually assists braking..........is there much difference in the "sensation" between the Separately Excited and the equivilent sized AC motor (425amp and 500amp, 25hp)......
Is this a controller question, do they control the "resistance you feel? 

I like the AC12/15's because of the higher Rpm's(7500rpm)......It seems that I could go up to 55mph for brief stints in a fixed ratio setup(thinking tadpole under 1200lbs. with 8.94 to 1 and 13" wheels/21" approx circumference)......

any input on this as well........also where should I post my 3 wheeler concept, "Builds"?

thanks much......................


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## major (Apr 4, 2008)

mettzman said:


> Mostley curios about how regen actually feels and how much it actually assists braking..........is there much difference in the "sensation" between the Separately Excited and the equivilent sized AC motor (425amp and 500amp, 25hp)......
> Is this a controller question, do they control the "resistance you feel?


Hi mettz,

I've used both AC and SepEx with regen. Both did very nicely in that regard. And for equal systems I suspect you would not know the difference.

However the AC systems I used were high voltage, higher power than the DC SepEx systems. So I don't have a fair A to A comparison. And the AC systems were more verastile inasmuch they could use a separate regen pot on the brake and were more programmable as to torque limit and cutout and such.

It is a system question as the controller can't do it alone.

And the system includes the energy storage system. Afterall, you need to put that kinetic energy somewhere as you slow the vehicle. With the right system you can equal the braking of the service brakes with regeneration right up to the point of traction of the tires.

Regards,

major


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## Salty9 (Jul 13, 2009)

There isn't a separate section for trikes you can find them by searching in the build forum.


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## mettzman (Mar 18, 2009)

Thanks guys!....I still have to scour the EVDL archives but that was my main question answered............

Here's another.........how do the HPG AC motors not have to run at those typical high voltages like the production vehicles.........the AC50 powers up to a 3600lb. vehicle and yet it's operable in the standard DC voltages........how are they different than the old classic AC systems and do they support the second brake pot?


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## frodus (Apr 12, 2008)

Its because motors are built for lower voltages, so are the controllers. They're made to be used with Forklifts, which aren't usually high voltage.

They're not normal 3-phase industrial motors, they're lower voltage.

Also, why would they need a second brake pot?


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## mettzman (Mar 18, 2009)

Major said "separate regen pot"..........makes sense.......


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## major (Apr 4, 2008)

mettzman said:


> Major said "separate regen pot"..........makes sense.......


Yeah, that's my preference. Proportional regenerative torque dependent on brake pedal travel or pressure.


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## frodus (Apr 12, 2008)

mettzman said:


> Major said "separate regen pot"..........makes sense.......


You said second brake pot.... I guess maybe you meant that you'd be using a Throttle pot and a Brake/Regen pot?

The way you said it, it sounded like two brake pots in addition to one throttle pot.


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## etischer (Jun 16, 2008)

I have two regen pots =)

One for braking,
and one for synchronizing the next gear change since I'm clutchless 



frodus said:


> You said second brake pot.... I guess maybe you meant that you'd be using a Throttle pot and a Brake/Regen pot?
> 
> The way you said it, it sounded like two brake pots in addition to one throttle pot.


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## major (Apr 4, 2008)

frodus said:


> You said second brake pot.... I guess maybe you meant that you'd be using a Throttle pot and a Brake/Regen pot?
> 
> The way you said it, it sounded like two brake pots in addition to one throttle pot.


Hi frodus,

Now that you mention it, I do often use two pots for the regen. One is on the brake pedal and a second one on the dash. It is an adjustment which is simply in series with the brake pot. That way I can tune the regen pedal to road conditions. Works very nicely. But the controller sees only a single regen input.

major


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## frodus (Apr 12, 2008)

interesting idea. I just hadn't heard of 2 regen inputs though, Sounds like maybe they're two in series?

I'd like to have a pot to vary the regen amount, and just have a brake switch toggle that on or off. Its for a motorcycle, so once its tuned, I'll probably change it much.


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## Coulomb (Apr 22, 2009)

mettzman said:


> How do the HPG AC motors not have to run at those typical high voltages like the production vehicles.........


My understanding is that they buy brand new standard voltage motors, then send them to a rewinder. They typically burn out the existing, brand new windings, and replace them with new coils using a smaller number turns of thicker wire.

The result is a motor that needs more current to achieve the same induced voltage, or looking at it the other way, with lower applied voltage, requires more current for the same torque. At the same speed, less voltage is induced in the coils, so there is less back EMF for the same speed. This allows the motors to run effectively the same as before, except at a lower voltage and higher current.

Hopefully if the volumes go up a bit, they can order a run of lower voltage motors from the factory, saving all that wasteful winding, burning, and rewinding, and lowering the cost. Even if they could order the motors with no windings (!), that would be a help. Maybe they already do this, I would not know.


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## mettzman (Mar 18, 2009)

Just the stuff I wanted to know, thanks guys............I love the dash knob or toggle idea alot..........and interesting about the rewinding on the HPG motors.........cheers....


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