Author Topic: Lister (oid) Dynastart  (Read 3308 times)

dieselspanner

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Lister (oid) Dynastart
« on: March 13, 2018, 06:50:57 PM »
So, back to the sordid subject of engineering!

There I was bumbling around on Youtube and I ran across this........

https://www.youtube.com/watch?v=IKqy3rRWJQE

A clip of a car alternator being used as a prime mover for a go cart, it must have some grunt to hit around 40 kph...

As is well documented on here, my knowledge of things electronical is somewhere on the sc an side of non existant and I ain't much better at things electrical either, I can copy and repair but innovation ain't me.

So, would it be possible / practical to use a 90 amp or so alternator to start a CS and then run as a alternator to charge the start battery (s) on either 12 or 24 volts?

I went on to read that most applications use a variable speed controller, of which there are umpteen on Ebay, however, it would appear that a simple controller, using 3 Hall Effect switches should suffice to power up at a given speed.

Looking at an alternator with a pulley for a serpentine belt that, been kicking around my shed for a while it would be running around 9/1 driving directly on to a 22" flywheel.

Has it been done, is it practical, do circuit diagrams for the 'speed controller'  already exist, ect, or have I beaten Elon Musk to the punch?

All answers (and any amount of derision!) appreciated.

Cheers Stef


Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

BruceM

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Re: Lister (oid) Dynastart
« Reply #1 on: March 13, 2018, 09:18:21 PM »
While it would be possible to use the alternator as both motor and alternator, I have not seen the circuitry to do the switch over dynamically but it could be done...crudely with some DC contactors/relays or better designed into and in addition to the 3 phase motor controller.  But note that you won't be getting 1500 watts of motor power if running the alternator motor on only 12VDC.  It makes sense to do it for lightweight, high efficiency vehicles (something American's seem to have no interest in at present) as it would save the weight of the starter and cost of the toothed flywheel.  It would normally require external diodes, which I think is the coffin nail; they need a lot of cooling so putting them in the alternator case for forced air fan cooling made more sense. 

For our home DIY generators it's easier with DC starter/charger units since they use a brushed DC motor which is already inherently a DC generator and thus no electronics required. A few guys have done this and I found one unit for sale for $100 US.  I think this would be my choice if starting over for a dedicated generator unit.

I was interested in doing a ST-3 generator/starter since I have 120VDC to drive it with, but the pathetic state of ST single phase head quality offends me so much that I won't develop anything for it. 

Thanks for the video link, it was fun watching that claw pole starter being abused as a 1500 watt motor on 48V. The smart and handy young man who did it and the video has a promising future.

« Last Edit: March 13, 2018, 09:25:04 PM by BruceM »

dieselspanner

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Re: Lister (oid) Dynastart
« Reply #2 on: March 14, 2018, 05:00:23 PM »
Hi Bruce,

It was the you guy's enthusiasm that made me think there might be something in it all.

I wasn't thinking of anything too technical, see the bit above about my level of knowledge!, more like mounting the alternator 'as is' and then supplying the power 'in between' the diode pack and the stator with something like a 3 phase relay to switch it and a control circuit with a rotor mounted between the alternator and the pulley with the 'doings' in a box elsewhere. Playing to the strength of generation rather than starting.

Given Glorts calculation on 14 volts could a 24 volt start system be used in the same way as the original 'Startomatic'?

Cheers Stef

 
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

ajaffa1

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Re: Lister (oid) Dynastart
« Reply #3 on: March 14, 2018, 11:09:52 PM »
My ST2 SOM requires 24 volt and specifies 118 amps for cold cranking, if that helps.
Bob

BruceM

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Re: Lister (oid) Dynastart
« Reply #4 on: March 15, 2018, 12:36:42 AM »
When I was first working out the cranking power needed for my 6/1  I started with a vee belt and small pulley on a Gast 3AM air motor, which is about 1 HP max rated; it was gutless and barely adequate.  The 4AM is rated 1.7HP and has plenty of power for starting with a rubber roller of 2.5" OD.  Air motors have moderate starting torque so you should be able to do a lower HP in electric.  I'm think you'd do fine with a 1.5 hp induction motor, for example. 

No reason you couldn't experiment away if you can get the parts cheap enough to give it a whirl.


ajaffa1

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Re: Lister (oid) Dynastart
« Reply #5 on: March 15, 2018, 05:41:19 AM »
Thinking back, I remember seeing a video on YouTube where a guy had rigged up an air powered starter with a small compressor and tank that charged up when the engine was running. Ozlisteroids I think. It was a very impressive system.

ajaffa1

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Re: Lister (oid) Dynastart
« Reply #6 on: March 15, 2018, 06:08:42 AM »
yes I think you might be right, I`ll check it out.

ajaffa1

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Re: Lister (oid) Dynastart
« Reply #7 on: March 15, 2018, 06:13:24 AM »