Ways to reverse Series DC Motor -100% FWD 30% RVRS

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Catavolt
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by Catavolt »

Here is an option to get reverse and small regen.

Couple a small 3ph induction AC motor to your existing motor no need for a clutch.
A .37-.75kw ($50-$100New)will be more than enough to push the Trike in reverse up to 15kph via your diff ,
A single phase AC motor controller will cost you around $150-$300 new this can be supplied by your main pack 200-400vdc,

This system won't effect you with normal driving at all as the AC induction motor will freewheel no cogging.

With this setup you can gain some engine brake and regen via the Small AC controller.

just a thought.
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Speedily
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by Speedily »

What a good idea :)
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by EV2Go »

Hmmm that would be interesting then I would be both AC & DC that's bound to get people talking Image.

Seriously though that sounds like a good idea. I couldn't see any weights listed but if the motor is only 1/2Hp it's probably the size of the motor on my drill press which isn't huge.

Let's see what the peeps say...

Edit:
Couldn't use that motor or would need 2:1 gear reduction but I'm sure there are other higher reving models.
Last edited by EV2Go on Wed, 27 Oct 2010, 10:29, edited 1 time in total.
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by Catavolt »

here is some specs of some Alloy motors.

http://www.teco.com.au/products.html?pa ... ge&product

If you would like to go that way I can send you more detail .
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by Johny »

I can't see a 1kW motor having enough torque to get the trike moving unless it has some serious speed reduction gearing (belting).
Can someone calculate the motor shaft torque required if EV2Go gives diff ratio, wheel radius and gradient please.
You also have the issue of fitting it in. Doesn't it have to sit above the big motor? I thought you were cutting off shafts to make room...
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by EV2Go »

If the motor was short enough I could probably squeeze it in front with the controller in the rear.

Diff ratio is 3.1:1, tyres are 235/45-17, incline minimal not likely to ever park anywhere too severe, and if I did I would reverse in and drive out.
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by Johny »

I get 24Nm to get you up a 3.3% grade.
Now that can be peak torque so 8Nm with a Tmax/Tn of 3 would be OK.
Ok I concede - 0.75Kw 8 pole would do. Since you don't need a lot of speed you don't even need a rewind. A 240VAC 3 phase motor, even though you could only provide 144 VAC (from 250VDC) would get you up to half motor speed with full torque (depending on controller being vector space).
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by Catavolt »

Have a chat to "acmotor" he put a 2pole 1.1kw into a car,
http://www.evalbum.com/1173
Ive used a .75kw AC at 4-1 in a motorbike with a 1.5kw drive I was able to do 60kph.

Last edited by Catavolt on Wed, 27 Oct 2010, 15:10, edited 1 time in total.
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by EV2Go »

9mph -14kph is more than enough for a reverse speed on a trike. A third of that would do me. I did notice there is a 20:1 reduction though to get it moving.

If you ran a reduction gearing like a flywheel / flexplate, obviously that will multiply the torque while reducing the speed, but what would that do to regen power?

Edit:
For regen wouldn't I want the biggest motor with the smallest weight?
Last edited by EV2Go on Wed, 27 Oct 2010, 16:56, edited 1 time in total.
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by Catavolt »

He used a 2 pole motor it has very little torque.

How much space do you have ?

Would you use a belt drive or direct couple?
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by Johny »

I messed up a bit. My figures were based on 24Nm rated torque and I had a Tmax/Tn of 3 (peak torque of 72Nm) which means it really looks more like a 1.5kW 8 pole motor with a 3-5kW controller to get 500kg up a 3.33% grade with tyres and diff as indicated. I realise the trike weighs more than 500kg but I forget the figure.
This is getting to be a big motor.

The reduction gearing you indicate means that the AC motor will spin too fast to use for regen above 20-30km/hr (it'll fly apart).

Not sure that all this extra weight just to go backwards is worth it.
If you are going to go for reduction gearing anyway just use a little DC motor. A bike starter or something with lots of gearing (chain/belt?) and the A/C clutch to minimise loss when not in use. No controller just a jog button with a lockout to somehow stop accidental use when moving forward.
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by Catavolt »

I would be very surprised if an .75kw motor doesn’t move the trike.


you will be surprised at how litle NM you need ,
Get a torque wrench put it on the input of the diff with the wheels on ajust it untill you get a NM reading.

Or a 1mt stick and a fish scale Image
Last edited by Catavolt on Fri, 29 Oct 2010, 02:52, edited 1 time in total.
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by EV2Go »

Max weight for the trike is 450kgs plus the lump sitting on it.

I really don't want anything more than a crawl, I think it will bearly get used. I planned to use a button and a jog or press with the starter motor but the idea of regen got me all excited again.
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Ways to reverse Series DC Motor -100% FWD 30% RVRS

Post by 7circle »

If you only want a crawl and don't have any other pumps to run off the motor needing a fan belt setup, the power supply idea could still be cheaper to intall.

It would be worth asking EV-netics about using separate power supplies to get reverse. They are the experts and know how to integrate a solution.
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