# forward /reverse switch for dual netgain warp 9 direct drive system



## Duncan (Dec 8, 2008)

muyen said:


> Hi there,
> 
> been doing some bench test on a netgain warp 9 motor with my new benchtop voltage regulator to test how the motor is spinning. now running into the challenge by switching from ccwr to cwr. the soliton 1 controller does'nt have the ability to switch forward and reverse rotation. and because i will let my dual netgain motors spin by direct drive i am concerned. that i wil burn my contactors. i have got an albright sw192B-24L switch contactor but i doubt this one can handle the amount of current that it wil recieve.
> do anyone know where to find or salvage a descent forward/reverse contactor or am i missing a clever switching layout with contactors to let the motors rotate the other way arrount?
> ...


You will need a reversing contactor - I'm using an Albright SW 202








Duncan's Dubious Device


Help Required! I have got a lovely big beefy reversing contactor - an Allbright SW202 However it has 36 volt solenoid coils - it takes 18 volt to pull in but it maintains down at 4 volts Any suggestions about how I use this on my 12 volt system?




www.diyelectriccar.com




Its a 36 volt unit so I'm using these dinky little voltage increase thingies to get my 12 volts up high enough to switch

The lower voltage reversing contactors are designed for smaller forklifts - so when you put the current up you need a bigger contactor
You could keep the contacts and just swap over the coils from one of the smaller ones - or just use the voltage boost thingies

Its not designed for the current I'm using (1200amps) - but it seems to be OK - once I gave its contacts a quick clean up


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## muyen (Dec 13, 2020)

thanks for your reply!
well if u have experiance in using the albright switch for 1200 amp then i am confendend to use my reversing contactor. 
seems like these contactors can handle some abuse. but i am sure that it doesnt like to disconnect when power of the "thinngy" cuts off. or when the coil will break up when the motor pulls some amps but that is just a factor of putting the contactor in a safe enclosure i guess. and also have a little luck 
do you clean the contacts on a regulair base?

To be honest, My REAL question was If i am burning my only reverse contactor Where to salvage a new one.
forklifts are a good suggestion thanks! 

i am thinking about a switching layout with gigavac for example to let both the motors spin in normal drive and let only one spin by switching it into reverse. 
the soliton does have settings (max power output) for reverse operation right. 
so in this case i dont need two reverse switching contactors 
ill make a scedule to show what i mean. my only concern is to permanently connect a motor with an "open" end) and using a gigavac is there enough "free"space between the contacts.

Groeten, Matthijs


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## muyen (Dec 13, 2020)

quick drawing in paint but the green lines and cross indicate the albright switching relays.
the black boxes are the gigavacs. 
and the red box indicate the soliton controller. 

in reverse mode only the front motor will spin.
i do have to set the soliton parameters on lower maximum current en voltage. 

Anyone a suggestion why i schould not do it this way?


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## Duncan (Dec 8, 2008)

muyen said:


> quick drawing in paint but the green lines and cross indicate the albright switching relays.
> the black boxes are the gigavacs.
> and the red box indicate the soliton controller.
> 
> ...


You are running the two motors in series - when you try to go to reverse one motor will try and go forwards and the other motor will try and go backwards - net result zero!

Why are you running in series? - for high current and high revs you need lots of volts - so halving the volts - from 340volt?? - is only 170 volts not very much


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## muyen (Dec 13, 2020)

Duncan said:


> You are running the two motors in series - when you try to go to reverse one motor will try and go forwards and the other motor will try and go backwards - net result zero!
> 
> Why are you running in series? - for high current and high revs you need lots of volts - so halving the volts - from 340volt?? - is only 170 volts not very much


when i will shift to reverse i will provide power to one motor and leave one end open.
So, one motor wil be connected and powered to drive reverse. 

it wil run with two motors in series when driving forward. 

battery pack will be 336v (80s2p configuration) enough to run in series right..


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## Duncan (Dec 8, 2008)

muyen said:


> when i will shift to reverse i will provide power to one motor and leave one end open.
> So, one motor wil be connected and powered to drive reverse.
> 
> it wil run with two motors in series when driving forward.
> ...





muyen said:


> when i will shift to reverse i will provide power to one motor and leave one end open.
> So, one motor wil be connected and powered to drive reverse.
> 
> it wil run with two motors in series when driving forward.
> ...


336 volts
Half is - 168 volts

That may be enough to drive 500 amps at 4000rpm - but not any more than that

If you wanted 1000 amps at 4000rpm then it will not be enough

You have two motors so I would assume that you want to "Use" some substantial power


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## brian_ (Feb 7, 2017)

muyen said:


> quick drawing in paint but the green lines and cross indicate the albright switching relays.
> the black boxes are the gigavacs.
> and the red box indicate the soliton controller.
> 
> ...


Because it would be more straightforward, and not require any change in motor parameters, to just use one more reversing contactor instead of two of the Gigavac contactors and use both motors all of the time.

But I agree with Duncan: two motors in series doesn't make a lot of sense. Why not just use one larger motor, which would need only one reversing contactor, and wouldn't be so ridiculously long?


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## muyen (Dec 13, 2020)

brian_ said:


> Because it would be more straightforward, and not require any change in motor parameters, to just use one more reversing contactor instead of two of the Gigavac contactors and use both motors all of the time.
> 
> *The gigavac's i was telling about operate @ 24 volts. so ill be missing the advanteges to use them without a voltage increase thingy... i intent to use 12 volt for the secondairy electric system. i just have to have a look for another reverse contactor.*
> 
> ...


This question would be like, why you dont buy a tesla...
let me explain.
i mentioned into the introduction section that i have bought a stranded project. 
the jaguar xk8 has been converted to electric in 2014? @ the pioneers from rebirth auto company florida. 
then it was shipped to the netherlands. for me its unknown what they have done to it here. (because the former owner had past away) but i can tell it is a real mess now. because i can see there has been some kind of majour short circuit.
So i am trying to rebuilt this car. using as mutch of parts that already come with the car.
the two netgain warp 9 motors came with the car, are still functionall, pictures on the internet and video's on youtube show that it drive's with them. they also use a evnetics solliton 1 controller. 
So i do not (yet) consider to purchase another motor.

The jaguar xk8 has got a long bonnet so the long motor will fit in when the gearbox is removed. 









And reply to duncan, 

The solliton 1 can handle as much as 342 volt's battery power.. and can deliver 1000A
so if i wil go higher in voltage i wil fry the controller??...
also,
The battery pack wil be build out of yuasa lev 50 lithium ion cell's. 
These cells are maximum rated 4,2 volt 50 ah. The whole pack is rated originally 300A continue power.
so placing 80 in serie's wil give me 336 volt. (the power that my elcon spf 2500 chargers can deliver).
i will repack the battery pack to 2 parralel cells and 80 in serie's so i have a 100 Ah pack.
i hope that the rebuild pack can deliver 600A continue current and a little bit more during peak (800 maybe 1000 AMP peak??) I still have to find a descent BMS to handle my requirements.

Or do you mean that the warp 9 motor's wont run above 4000 rpm applying 168 volt?


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## Duncan (Dec 8, 2008)

Hi - the motors will run fine
The issue is the back EMF - which means that you need volts to overcome the back voltage and the back voltage is caused by current multiplied by rpm
So with only 168 volts you will probably not be able to maintain 1000 amps much past 3000 rpm - if that high!
As you go faster the current will drop - won't hurt anything just won't push as hard - by 4000 rpm it will probably be down to 500 amps

Contactors
I started using a 24v reversing contactor with my 12v system - worked OK
Then I upsized to a 36 volt reversing contactor - that did not work on 12v - so I had to buy one of those dinky little voltage increasers









Duncan's Dubious Device


Help Required! I have got a lovely big beefy reversing contactor - an Allbright SW202 However it has 36 volt solenoid coils - it takes 18 volt to pull in but it maintains down at 4 volts Any suggestions about how I use this on my 12 volt system?




www.diyelectriccar.com





You may be able to get away with a 24 volt unit just using 12 volt

But if not those voltage increase units are cheap


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## brian_ (Feb 7, 2017)

muyen said:


> This question would be like, why you dont buy a tesla...


No, buying one more contactor to make the configuration rational is nothing like buying a whole new car.


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## muyen (Dec 13, 2020)

brian_ said:


> No, buying one more contactor to make the configuration rational is nothing like buying a whole new car.


I reverted to the quote: Why not just use one larger motor, which would need only one reversing contactor, and wouldn't be so ridiculously long?


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## brian_ (Feb 7, 2017)

muyen said:


> I reverted to the quote: Why not just use one larger motor, which would need only one reversing contactor, and wouldn't be so ridiculously long?


Ah, okay.... but one big obsolete lump of motor (instead of two smaller ones) is also not the same as buying a Tesla.


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## muyen (Dec 13, 2020)

Duncan said:


> Hi - the motors will run fine
> The issue is the back EMF - which means that you need volts to overcome the back voltage and the back voltage is caused by current multiplied by rpm
> So with only 168 volts you will probably not be able to maintain 1000 amps much past 3000 rpm - if that high!
> As you go faster the current will drop - won't hurt anything just won't push as hard - by 4000 rpm it will probably be down to 500 amps
> ...


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## muyen (Dec 13, 2020)

So if i understand you right,
the car will rocket to say 4000 rpm and then has got half the power to reach a higher rpm. 
but will eventually reach 6000 rpm? 

4000 rpm including gear ratio from the diff 3.42 and tire diameter of 640mm wil be around 140 km/h 
with 6000 rpm it will reach 212 km/h 
I guess i can live with that speed.

i thought that a electric motor needs the amps to produce torque to get the car moving but eventualy will need volt's to increase the rpm's and speed

cant i set the soliton to a higher voltage output.
do you know how much volt a netgain warp 9 kan handle ?
and how do those dragster guys with those dual motor setup run their machines?


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## muyen (Dec 13, 2020)

brian_ said:


> Ah, okay.... but one big obsolete lump of motor (instead of two smaller ones) is also not the same as buying a Tesla.


Also not very DIY


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## brian_ (Feb 7, 2017)

muyen said:


> Also not very DIY


A different old lump of motor is less DIY than two smaller old lumps of motor? I don't understand that... but it's your car, so you can do what you want. Just don't expect kludging something together from an incomplete set of parts purchased by someone else (and already proven to not work properly) to be easy to make work, or to work well.


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## Duncan (Dec 8, 2008)

brian_ said:


> A different old lump of motor is less DIY than two smaller old lumps of motor? I don't understand that... but it's your car, so you can do what you want. Just don't expect kludging something together from an incomplete set of parts purchased by someone else (and already proven to not work properly) to be easy to make work, or to work well.


I would disagree
I would NOT start with two motors
But if you have two motors then its not a big problem and should make a reasonable machine - use what you HAVE 
Two Warp 9's and a Soliton represent a fair amount of money - over $10,000 
Their re-sale value is a lot less
So make use of them


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## brian_ (Feb 7, 2017)

Duncan said:


> But if you have two motors then its not a big problem and should make a reasonable machine - use what you HAVE
> Two Warp 9's and a Soliton represent a fair amount of money - over $10,000
> Their re-sale value is a lot less
> So make use of them


Sure, ,that logic makes sense... so buy one more reversing contactor to use them rationally. If the only wire which came with this failed project was far too small-gauge to use safely, would you be scheming some way to make it work with that? No? Then why devise the most bizarre wiring scheme possible to make it "work" with only one of two required reversing contactors?

And I thought all the brushed DC series-wound motor fans insisted that they are free for the asking, so while the Soliton is valuable the WarP 9's are worth nothing, right?


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## Duncan (Dec 8, 2008)

brian_ said:


> And I thought all the brushed DC series-wound motor fans insisted that they are free for the asking, so while the Soliton is valuable the WarP 9's are worth nothing, right?


Not "free" - but inexpensive 
More importantly getting rarer - after about 2005 forklifts went AC so the supply will be drying up

And the "Cost" does not represent the "value"

As I said - "their resale value is a lot less"


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## muyen (Dec 13, 2020)

brian_ said:


> Then why devise the most bizarre wiring scheme possible to make it "work" with only one of two required reversing contactors?


Because of the availebility of reversing contactors wich can handle 1000 amps
the most contactors i could find go up to 300 amp and are electric winch contactors.

and i got my hands on those 400 amp rated gigavacs for cheap.

and i have drawn the wiring sheme before i knew that most reverse contactors are heavyly being abused 
(can handle some overload). 

and i dont like the risk of a sticked contactor and with doubleing the amount of flimsy contactors double the risk. 

and with a setup ive seen from ZEVA i am sure it can be used with one reverse contactor and one normal contactor.


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## brian_ (Feb 7, 2017)

Duncan said:


> Not "free" - but inexpensive
> More importantly getting rarer - after about 2005 forklifts went AC so the supply will be drying up
> 
> And the "Cost" does not represent the "value"
> ...


No, some members claim that you can just ask for these things... but I do understand that the more common suggestion is that they can be bought for scrap metal value. And surely the resale value of a Netgain motor (which was overpriced to buy originally) is at least scrap value.

It's likely that in reality most DIY builders will not be able to get a suitable brushed DC series-wound motor any more cheaply than buying a used one from an online listing. Please note the winky emoticon on my "free motor" comment.


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