# Low torque series wound motor on Gokart



## Pota (Nov 25, 2017)

I have a prestolite Series wound motor at 82lbs.

I have Connected the motor to a Evnetics Solition Jr. 600amp Controller, and i am running it at 600amp.

Ive added 20s1p (72v) Lithium Ion batteries and they easily deliver 600amp.




The gokart's gear ratio is 1:1.

The problem is that its not doing burnout before 480amp and thats without me in it.
And with me in it, its alot weaker even when drawing 600amp. 
Im very frustrated because this guy

https://www.youtube.com/watch?v=KObUDN7pMcE

Is running 500amp at 110v. 1:1 ratio and are doing INSANE burnouts and speed even with less amp. He got the same motor as me.




Someone have any idea whats wrong?

Thanks alot for all replies!


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## jbman (Oct 26, 2017)

The comments say he's running 1.25:1 gear ratio. Dunno if that's enough to account for what you're experiencing.

Sent from my SM-N960U using Tapatalk


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## Pota (Nov 25, 2017)

jbman said:


> The comments say he's running 1.25:1 gear ratio. Dunno if that's enough to account for what you're experiencing.
> 
> Sent from my SM-N960U using Tapatalk


No faar from it. I was running 2.25:1 before. It went better, but still not the way he is. im FAAR from it


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## jbman (Oct 26, 2017)

Pota said:


> No faar from it. I was running 2.25:1 before. It went better, but still not the way he is. im FAAR from it


What tires, etc? That could make a pretty gigantic difference.


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## Pota (Nov 25, 2017)

I mean, mine is REALY slow compared to his starting torque. He has abit wider tires. 
Mine are hard, old, cold (since im in Norway) and that would equal easier slipping.


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## major (Apr 4, 2008)

Sounds like primarily a ratio problem. Typically karts run 4 or 5:1. Also, could be excessive brush advance. What is motor part#? Photo of motor? 

major

ps. Be careful. If chain breaks or comes off at full throttle, motor is likely to blow up.


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## Duncan (Dec 8, 2008)

Hi Pota

You need to go into your controller's setup menu - something is wrong! - 

I suspect that the controller is either de-rating because of voltage sag or the ramp up is set too slow

Go into setup and make sure that all of the settings are ok


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## ishiwgao (May 5, 2011)

Pota said:


> The problem is that its not doing burnout before 480amp and thats without me in it.
> And with me in it, its alot weaker even when drawing 600amp.


is this 600amp what you confirmed by the settings in the Soliton controller, or something you confirmed using a current sensor on your batteries?

I remember reading somewhere on this forum that solitons have some safety feature so what you set might not be what it is actually pulling through the controller. you need to do some changes in the settings page of the controller.

Just a guess.


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## Pota (Nov 25, 2017)

No Major, shouldent be a problem. The man on the video is going for 1.16 : 1 .... And it BURNOUT like hell... He has the Paul And Sabrina 500amp controller, Mine is 100amp more.


Yes he is using 110v and i 74v. But the difference is INSANE, mine wont start to spin without me in it, before hitting 480amp... And with me sitting in it, its alot slower and ofc wont burnout...

Im using the Evnetics logging. It says im pushing 600amp throttle and 595 + - motor amp. I used the logging while standing still and throttle it to max AND while running with me in the kart.

There must be something wrong, but im still unsure what :S


Controller settings looks good. 600amp battery and motor. 25000amp/sec increase when pressing full throttle. 


Its a Prestolite MTY4001RU (Remanufactured). It weights 86lbs.


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## Pota (Nov 25, 2017)

Note. this is the same motor. But with paul and sabrina 500amp controller, that would be 100 less than the Evnetics Soliton Jr. and he has around 1:1 gear ratio. He do uses 110v but the difference as stated earlier is INSANE. Ive tried 84v. 

https://www.youtube.com/watch?v=BGwtqgN_7no


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## jbman (Oct 26, 2017)

Pota said:


> Note. this is the same motor. But with paul and sabrina 500amp controller, that would be 100 less than the Evnetics Soliton Jr. and he has around 1:1 gear ratio. He do uses 110v but the difference as stated earlier is INSANE. Ive tried 84v.
> 
> https://www.youtube.com/watch?v=BGwtqgN_7no


Something isn't adding up. You should get a clamp meter or something and see what it reads. 500 amps is a lot for a vehicle like that. I dont think you're getting near that much juice.

Sent from my SM-N960U using Tapatalk


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## Pota (Nov 25, 2017)

jbman said:


> Pota said:
> 
> 
> > Note. this is the same motor. But with paul and sabrina 500amp controller, that would be 100 less than the Evnetics Soliton Jr. and he has around 1:1 gear ratio. He do uses 110v but the difference as stated earlier is INSANE. Ive tried 84v.
> ...


So true. Its very very strange. Ill buy a clamp meter tomorrow.


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## Pota (Nov 25, 2017)

If it isent the amp delivery. And that is ok. What could it be. Something wrong with the series wound motor? In that case. What?


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## Pota (Nov 25, 2017)

Okay, the results are in, ive bought a clamp-meter.

I tested it now at 12s1p. around 48v.

At full throttle it started to spin the wheels at 480amp. 1:1 gear ratio. This test is done by placing the GoKart against the wall with noone sitting in it. Ill guess its around 60-80kg weight at the back wheels.

Full amp peak was 662amp.

Well, that would conclude that the controller is in good shape. But what could it be then. 
What in the motor could make it so damn much too weak? I mean, this is a series wound motor, and they should have the greatest torque capacity.

I mean this guys running 1.16:1 gear ratio with only 500amp. and same controller.

https://www.youtube.com/watch?v=BGwtqgN_7no


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## major (Apr 4, 2008)

Some thoughts:

Are you sure it is series wound? Not SepEx.

Is it wired correctly? Please post photos of the installation.

Are you willing to do a stall test to measure the actual torque? Need a torque arm on the wheel and spring scale. Measure motor amps and hold on for just a few seconds so you don't damage (lift) comm bars under the stationary brushes. Torque wrench could work as long as it tends to tighten axle nut.

major


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## Pota (Nov 25, 2017)

major said:


> Some thoughts:
> 
> Are you sure it is series wound? Not SepEx.
> 
> ...



First of, thanks for all the help guys, this means so much to me.

Here are some pictures of my motor and brushes.
Its a Prestolite MTY 4001. 7.2inch wide, 86lbs. 
A total of 8 brushes.

On the right side of the motor is the connection S-1 in upper right and S-2 i lower right. A-1 in upper Left and A-2 in lower left.

Ive connected it in the following way.
Plus to S-1
S-2 to A-1
Ground to A-2

Ive added multiple pictures


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## Duncan (Dec 8, 2008)

You are well down on torque - as in 80% down

But you are drawing the current
The only thing that I can think of is that the motor has had it's brushed advanced and somebody has dropped a cod

I have 8 degrees of advance on my motor - that has the effect of dropping the initial torque by about 20%

I believe that 45% of advance would essentially mean that the motor delivered zero torque

So my 8 degrees drops initial torque by about 20% - I do get it back at about 60 kph

- 30 degrees would probably drop your torque by about 80%

That the ONLY thing that I can think of that would allow the current through without giving you the torque


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## Pota (Nov 25, 2017)

Duncan said:


> You are well down on torque - as in 80% down
> 
> But you are drawing the current
> The only thing that I can think of is that the motor has had it's brushed advanced and somebody has dropped a cod
> ...


Ohhh, sounds reasonable. But by looking at my brushes. Can you say something about if it Advanced? 
And how do i diagnose the problem, and what do i do to advance them?


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## Duncan (Dec 8, 2008)

Look at the bolts that hold the field coil laminations in place

They should line up with the brushes for neutral timing - when I say the brushes I mean the middle of the contact patch on the armature

Post some pictures showing the brushes and the bolts for the field coils in the same picture and I hope that a real expert like Major will chime in

It is possible that the current is going through the wrong path (shorting) but I would expect 500 amps to spark and smoke


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## Duncan (Dec 8, 2008)

Look at the bolts that hold the field coil laminations in place

They should line up with the brushes for neutral timing - when I say the brushes I mean the middle of the contact patch on the armature

Post some pictures showing the brushes and the bolts for the field coils in the same picture and I hope that a real expert like Major will chime in

It is possible that the current is going through the wrong path (shorting) but I would expect 500 amps to spark and smoke


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## Pota (Nov 25, 2017)

Ill try take some Pictures and so on 

And ill give you feedback!


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## Pota (Nov 25, 2017)

Ok here are some new updates 

Ive taken some pictures. If you look at the picture, it seems that the brushes are pretty alligned with the field coils?

It must be said. If you look at the brushes and how they bend towards the right. the motor is running CCW not CW (in other words, the motor is turning around towards left). Could that have something to do with it?

As you see, ive removed one brush. And as earlier stated, its 8 brushes in total.


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## Pota (Nov 25, 2017)

Someone got a clue ?


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## major (Apr 4, 2008)

Pota said:


> Someone got a clue ?


Actual measured torque/motor current would be big help.



major said:


> Are you willing to do a stall test to measure the actual torque? Need a torque arm on the wheel and spring scale. Measure motor amps and hold on for just a few seconds so you don't damage (lift) comm bars under the stationary brushes. Torque wrench could work as long as it tends to tighten axle nut.
> 
> major


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## Pota (Nov 25, 2017)

major said:


> Actual measured torque/motor current would be big help.


Im not actualy sure how i can do it on my gokart, i need to weld something to the axle then?


But if that give you an X result. What could be done? I mean, is there something with my brushes? CCW rotation? 

What else could it be?


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## major (Apr 4, 2008)

Pota said:


> Im not actualy sure how i can do it on my gokart, i need to weld something to the axle then?
> 
> 
> But if that give you an X result. What could be done? I mean, is there something with my brushes? CCW rotation?
> ...


I just want to verify it is actually low motor torque per motor ampere. No, do not weld anything to axle. You need to measure the force at a known distance from the center of rotation. So hold the kart frame still and measure force at tire raduis. Or hold tire steady and measure force on a tangent point on kart frame.

Like clamp the rear wheel to the floor with straps. Now when you press throttle, the front of the kart will try to wheelie, right?. Let's say the very front of the frame is 4 feet from the rear axle. It requires you to apply 50 pounds vertically to lift it just off the floor. Now repeat with full throttle. Say it then only requires 10 pounds vertical force to lift. The motor is responsible for the other 40 pounds of force. At 4 feet from the axle, motor stall torque is 160 pound feet (lb.ft.). Say you had measured 500 motor (not battery) Amperes for that test. Or 32 lb.ft./100A. That is a figure I can use to verify that the motor is in the ball park.

The numbers which I used were example only. Your motor appears well used. It could have a problem. From what I can see in your nice photos, brush advance is ok.

major


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## Pota (Nov 25, 2017)

major said:


> I just want to verify it is actually low motor torque per motor ampere. No, do not weld anything to axle. You need to measure the force at a known distance from the center of rotation. So hold the kart frame still and measure force at tire raduis. Or hold tire steady and measure force on a tangent point on kart frame.
> 
> Like clamp the rear wheel to the floor with straps. Now when you press throttle, the front of the kart will try to wheelie, right?. Let's say the very front of the frame is 4 feet from the rear axle. It requires you to apply 50 pounds vertically to lift it just off the floor. Now repeat with full throttle. Say it then only requires 10 pounds vertical force to lift. The motor is responsible for the other 40 pounds of force. At 4 feet from the axle, motor stall torque is 160 pound feet (lb.ft.). Say you had measured 500 motor (not battery) Amperes for that test. Or 32 lb.ft./100A. That is a figure I can use to verify that the motor is in the ball park.
> 
> ...


Aha ok, just some questions so i know how to do it.

I clamp the rear tires to the ground with some sort of strap. 
Then i messure the force it tries to lift the cart from the very front. in other words. the metall where the front bumper is connected.
Then I measure the distance from the rear axle to the front where i attatch the weight scale?

What kind of weight scale can i use? 
Is it ok that i use kilo or gram as measurement?

In that case its having little torque for each amp. What could it be? Something i can check on the motor now while its apart?

But i think im like lacking 80% torque. Even with 2.25:1 ratio it wouldent do burnout from start. And i mean, look at the movie... insane burnout with 1.16:1 ratio


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## MalcolmB (Jun 10, 2008)

Can you get a clear picture of the commutator surface? It looks a bit rough to me. If you could at least remove a pair of brushes and get a clearer photo it would help. I have a similar Prestolite motor on which the commutator/brushes were slightly contaminated by a brake fluid leak. This damaged the commutator film and had a big effect on the motor performance.


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## major (Apr 4, 2008)

Pota said:


> Aha ok, just some questions so i know how to do it.
> 
> I clamp the rear tires to the ground with some sort of strap.
> Then i messure the force it tries to lift the cart from the very front. in other words. the metall where the front bumper is connected.
> Then I measure the distance from the rear axle to the front where i attatch the weight scale?


Yes.

For reference.
https://www.khanacademy.org/science/physics/torque-angular-momentum/torque-tutorial/a/torque



Pota said:


> What kind of weight scale can i use?
> Is it ok that i use kilo or gram as measurement?


Sure. Just do units conversion.

Spring scale for pulling force. It like a bathroom scale for pushing force, in which case it'd be under the front of the kart (weighing it). You could even use a balance method. Apply some ingenuity.


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## Pota (Nov 25, 2017)

major said:


> Yes.
> 
> For reference.
> https://www.khanacademy.org/science/physics/torque-angular-momentum/torque-tutorial/a/torque
> ...


Ohh i see, so i can just have it on the front, first see the weight of the gokart, then see how much it lightens?


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## Pota (Nov 25, 2017)

Okay, new update!

Ive disasambled the motor. Took some pictures, maybe you can study and find anything upsetting  ?

I also checked the armature for damage using the multimeter on the commutator. 
1. 180degree test - OK
2. side by side commutator bar test - OK
3. Ground on the shaft and checked for any continuity with the commutator bars - OK

BUT i did feel, that when doing the tests. it was easier to get the readings when i was on the copper colored bars top and bottom (where the commutator havent touched), in the middle where the bars are more black, it took alittle while to get the readings, i needed to "scratch" abit to hit the copper.

Here are the pictures, take a look


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## Pota (Nov 25, 2017)

Does it seem OK?


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## major (Apr 4, 2008)

Pota said:


> Does it seem OK?


From what I can see, yep. Well used. Field coils are really dark but likely seeing a coat of graphite dust. Can't see any burns or rubs. Comm surface isn't the best, but not bad. You should not touch it let alone scratch it with probes.

I think torque test is way to tell where problem lies.

major


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## MalcolmB (Jun 10, 2008)

Major is the expert, but your commutator surface looks very similar to mine after it was contaminated with oil. I also found that the brushes were binding in their holders, which probably didn't help. I've not attempted to fix the problem, as I plan to use a different motor now.

I also found this pdf from Helwig, which may help identify the problem. The first photo on the second page looks close to your photo.

http://perkinspowerproducts.com/wp-...comm-condition-guide-broch-ta4-hi-res-web.pdf

Just realised Major answered before me. I'd follow his advice first.


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## Pota (Nov 25, 2017)

major said:


> From what I can see, yep. Well used. Field coils are really dark but likely seeing a coat of graphite dust. Can't see any burns or rubs. Comm surface isn't the best, but not bad. You should not touch it let alone scratch it with probes.
> 
> I think torque test is way to tell where problem lies.
> 
> major


Good, ill do a torque test, and return the results. 

I know alot of people are using very fine sand paper to remove the dark fields. Maybe using a drill while holding it steady.
Is that ok?

BTW: How do i clean the motor, any tutorials?


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## major (Apr 4, 2008)

Pota said:


> Good, ill do a torque test, and return the results.
> 
> I know alot of people are using very fine sand paper to remove the dark fields. Maybe using a drill while holding it steady.
> Is that ok?
> ...


No sandpaper or abrasives. Soap and water, rinse and dry. Or just clean compressed air. No oil, no chemicals.


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## Pota (Nov 25, 2017)

major said:


> No sandpaper or abrasives. Soap and water, rinse and dry. Or just clean compressed air. No oil, no chemicals.


Can i use soap and water inside the whole motor, except the ballbearings?


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## major (Apr 4, 2008)

Pota said:


> Can i use soap and water inside the whole motor, except the ballbearings?


Yes.
..............


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## Pota (Nov 25, 2017)

major said:


> Yes.
> ..............


You are the specialist.

What kind of power can we expect from a Prestolite/Raymond MTY4001?
Given example. 600amp and 84v?

As you see in the movie, he flips the gokart and do insane burnouts, kinda cool.

Torque newtonmeter? 84v*600amp should after all be 50400kw.


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## Russco (Dec 23, 2008)

Pota said:


> Good, ill do a torque test, and return the results.


Do you have the specs. and curves for your forklift motor?

I have had a lot of experience with the Prestolite MTC-4001 motors, which were very popular for EV conversions in the 80' and 90's, but curves were available. 

To determine the torque of the motor, mount a 2' x 4' sheet of plywood on the motor flange with the motor shaft protruding thru a 4" hole cut in the plywood. Locate a coupling that will fit the motor shaft with a flat end. Mount the coupling on the motor shaft along with a disc you make from 1/2" steel that bolts to the end of the coupling. This disc will need a 1/2" square hole machined in the center.

Place the motor upright and insert a 1/2" beam type torque wrench into the square hole on the motor shaft and drill a 3/4" hole in the plywood and insert a 3/4" cap screw, washers and nut so the bolt hits the pivot in the plastic torque wrench handle.

Connect the wiring from the motor to the controller, note the motor rotation and place the torque wrench handle on the proper side of the bolt in the plywood.

Start at low amps, like 50, and note the torque wrench torque. Then go up to 100 amps and note torque. Note torque up to 600 amps and graph.

Torque vs. amps should be a straight line on your graph. Could be 100 -200 foot pounds at 600 amps.

Locating the factory hp, torque, and rpm graphs will be very important to seeing what's going on.


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## major (Apr 4, 2008)

Pota said:


> You are the specialist.
> 
> What kind of power can we expect from a Prestolite/Raymond MTY4001?
> Given example. 600amp and 84v?
> ...


It is very similar to the MTC type motor.










You can see the torque per amp. And efficiency in the 500A region is like 75-80%, so that should give you close approximation of power out.

Another interesting doc.
https://www.google.com/url?sa=t&sou...FjAAegQIBRAB&usg=AOvVaw0yWIHRvp7ofCvHUJyVuTYw

major


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## Pota (Nov 25, 2017)

Russco said:


> Do you have the specs. and curves for your forklift motor?
> 
> I have had a lot of experience with the Prestolite MTC-4001 motors, which were very popular for EV conversions in the 80' and 90's, but curves were available.
> 
> ...


Im quite sure this motor aint delivering 200 foot pounds now  Then it would flip the kart haha.

Did you read Majors post on testing the torque? Wouldent that give us the same results?

I dont know if i can find info on the MTY4001. I know its 86lbs just the motor. MTC-4001 seems to be 100lbs with all mounting hardware attatched. Im not sure which one of them is the strongest. I got 8 brushes, and the MTC have 4.
Seems that the MTY is stronger?


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## Pota (Nov 25, 2017)

major said:


> It is very similar to the MTC type motor.
> 
> 
> 
> ...


Very nice!

Regarding the stall test. Does it matter if i weight the front of the gokart, and then use 300amp stall test, and then weigh the front, OR do i need to use all 600amps?
I mean, it would be harder on the motor to stall 600amp for some seconds than 300amp.
Or would it not be precise if i dont go all out 600amp?


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## Russco (Dec 23, 2008)

Pota said:


> Very nice!
> 
> Regarding the stall test. Does it matter if i weight the front of the gokart, and then use 300amp stall test, and then weigh the front, OR do i need to use all 600amps?
> I mean, it would be harder on the motor to stall 600amp for some seconds than 300amp.
> Or would it not be precise if i dont go all out 600amp?


Since current is proportional to torque, as shown in the graphs, use of a smaller current is fine. Example: If 200 amps is 33 foot pounds, 600 amps = 99 foot pounds.

If your rear axle has a hex nut, a beam torque wrench with a hex socket (not 12 sided) will work. I assume the rear axle is a one piece axle, so both rear wheels must be jacked up and the torque wrench handle supported on a block of wood on the ground. Be careful that the wrench doesn't come off of the axle nut or the block of wood falls out of place, or the car will move forward or backward. Oh, and pick the side of the car that will tighten the axle nut, not loosen it. Block both front wheels on both sides. This is a hokey method. Be careful.


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## Pota (Nov 25, 2017)

Russco said:


> Since current is proportional to torque, as shown in the graphs, use of a smaller current is fine. Example: If 200 amps is 33 foot pounds, 600 amps = 99 foot pounds.
> 
> If your rear axle has a hex nut, a beam torque wrench with a hex socket (not 12 sided) will work. I assume the rear axle is a one piece axle, so both rear wheels must be jacked up and the torque wrench handle supported on a block of wood on the ground. Be careful that the wrench doesn't come off of the axle nut or the block of wood falls out of place, or the car will move forward or backward. Oh, and pick the side of the car that will tighten the axle nut, not loosen it. Block both front wheels on both sides. This is a hokey method. Be careful.


Ohh good. No, it doesent have any nut. The wheels is fastened with 3 hex sockets.
But tbh, i realy dont have any good idea how to fasten it


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## Pota (Nov 25, 2017)

Uhm, and one more thing. 
Does the rotation of the motor spinning has anything to do with the torque?


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## Russco (Dec 23, 2008)

Pota said:


> Ohh good. No, it doesent have any nut. The wheels is fastened with 3 hex sockets.
> But tbh, i realy dont have any good idea how to fasten it


Make a 1/4" circular steel plate like a wheel cover with three holes that mount on the three studs on the axle hub. Weld a 1/2" drive socket to the center of the steel plate. Press the torque wrench into the socket.

Why not just make a small 1/2" aluminum disc that mounts on the end of the motor sprocket with four bolts that touch the inner circles of four of the sprocket teeth. The disc will need a 1/2" square hole for the torque wrench. Remove chain, of course.

You can reverse the motor field to test forward and reverse torque to verify they are somewhat the same.


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## bigmotherwhale (Apr 15, 2011)

Pota said:


> Uhm, and one more thing.
> Does the rotation of the motor spinning has anything to do with the torque?


I would try running it in reverse and see if it has better torque in that direction. Change the polarity of either of the coils or and the motor only, swap the stator and leave the rotor and it will run in in reverse 
Let me know what you find.


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## electro wrks (Mar 5, 2012)

Let's get back to basics here. What size wire leads are you running from the battery to the controller, and from the controller to the motor. They look a little undersized and maybe a bit frayed at the terminals in your photos. A voltage drop test at the motor terminals, when the motor is under load, might be useful to test for this problem.


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## Pota (Nov 25, 2017)

electro wrks said:


> Let's get back to basics here. What size wire leads are you running from the battery to the controller, and from the controller to the motor. They look a little undersized and maybe a bit frayed at the terminals in your photos. A voltage drop test at the motor terminals, when the motor is under load, might be useful to test for this problem.


They are 25mm2.

Would they be to small?


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## electro wrks (Mar 5, 2012)

70mm2 (#00 AWG) would be better. The 25mm2 is rated for ~170A continuous, the 70mm2 ~490A continuous. Check the voltage drop to be sure.


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## Pota (Nov 25, 2017)

electro wrks said:


> 70mm2 (#00 AWG) would be better. The 25mm2 is rated for ~170A continuous, the 70mm2 ~490A continuous. Check the voltage drop to be sure.



Yes, but i measured 662amp to the motors. I mean, its ok the voltage drop is 30%... BUT it doesent explain the insane loss of torque.


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## Duncan (Dec 8, 2008)

Looking at Major's graph it looks like 90 lb ft at 600 amps

Kart weights - 100kg + 100 kg of driver

100 Kg on rear wheels - 12 inches diameter? - rear wheel torque is 90 ft lbs - 180lbs - 80 Kg at the tyre

That would not spin the tyres

Lifting the front wheels - Kart is 3 ft wheelbase - 100 kg on front wheels 

90 ft lbs would only give 30 lbs or 13 kg lifting at the front

From that motor diagram maybe that is what you are going to get

I wonder if the guy pulling wheelies had set his kart up with almost no weight on the front wheels 

Or he was running 4:1 on a ratio

he mentions a top speed of 80 mph at 110v - that ties into a reduction gear of 2:1 or 3:1


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## Pota (Nov 25, 2017)

Duncan said:


> Looking at Major's graph it looks like 90 lb ft at 600 amps
> 
> Kart weights - 100kg + 100 kg of driver
> 
> ...


Its more like 120ft lbs. comparing to the pdf Major sent.
But as stated, the guy running the kart on youtube is larger than mine, its also same motor, and 500amp contoller. I maxed out at 665amp. that would be closer to 130ft lbs.
He also stated the gearing was 1.25:1 or 1.16:1.

https://www.youtube.com/watch?v=XsutcOljO7A

Im not even having burnouts With 2.25 : 1 gearing.

https://www.youtube.com/watch?v=JF9K2GbUiMQ

Looking at the Chain, you can clearly see that its more close to 1:1


AND if you take a look at this video
https://www.youtube.com/watch?v=YPl6U_ez_K4
This is still the same motor, but With 55volt, 350amps(Alltrax Controller) and 1.21 : 1
Im still nowhere near that amount of Power.


Note:
Mine weights around 50-70kg at the back. With 1:1 gearing it dident start to spin the tires before hitting 480/500amp. And that was without me in it.


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## bigmotherwhale (Apr 15, 2011)

have you tried reversing the motor direction yet?


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## Pota (Nov 25, 2017)

major said:


> It is very similar to the MTC type motor.
> 
> 
> 
> ...


FINALY Major and the rest 

I have done the torque test! Strapped the wheels to the ground 

Here are some information.

- From the rear axle to the front where i weight the front, it was 139.5cm
- The weight at the front was 23.3kg.
- I adjusted the controller to 300amp. (320amp measured with clampmeter)
- 12s1p 48.2v battery.

When i maxed out the throttle (320amp) the front went from 23.3kg to 19.55kg = 3.75kg difference.


Voltage drop 48.2 - 46.9 = 1.3v drop on 12s1p batteries.


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## Duncan (Dec 8, 2008)

So 3.75 kg at 139 cm

That is 52 Nm - or 37 lb ft - about 75% of the predicted torque from the chart


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## Pota (Nov 25, 2017)

Duncan said:


> So 3.75 kg at 139 cm
> 
> That is 52 Nm - or 37 lb ft - about 75% of the predicted torque from the chart


Pretty faar away from this 

https://www.youtube.com/watch?v=BGwtqgN_7no

Remember. i have MTY4001. Not MTC.

The weight of the front was without me in it. With me its around 50kg.
That means i need 4000amp to wheelie me. Isent that kinda strange he so easily does it with even more weight at the front, and 500amp / same motor?


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## major (Apr 4, 2008)

Good goin' with the test. Shows you're in the ball park with actual torque/amp. Be nice to do same test in reverse motor rotation. That could verify neutral brush advance. But isn't likely to find a gob of torque.

So like I said before, you need more leverage from the sprocket ratio. As far as the guy wheeling over, could be weight distribution??? Or that motor can tolerate a couple kA for a few seconds.

major


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## Pota (Nov 25, 2017)

major said:


> Good goin' with the test. Shows you're in the ball park with actual torque/amp. Be nice to do same test in reverse motor rotation. That could verify neutral brush advance. But isn't likely to find a gob of torque.
> 
> So like I said before, you need more leverage from the sprocket ratio. As far as the guy wheeling over, could be weight distribution??? Or that motor can tolerate a couple kA for a few seconds.
> 
> major


Ok, thats good, but what i think is kinda special. Is that on both the wheelie and the burnout videos, he still pushes only 500amp. and have the ratio of 1.25 : 1. Im pretty faar away from that. And im not even sitting inside the kart 

He even have strong burnouts with 350amp and 70v 2.22:1. than i have with 662amp and 80v at 2.25 : 1.
See this from 1.52.
https://www.youtube.com/watch?v=88j_YBTMUFM


Even these kids are having insane burnouts 
https://www.youtube.com/watch?v=bERjkSTYOdU

With a smaller 6.7" motor.


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## major (Apr 4, 2008)

Pota said:


> ...
> Even these kids are having insane burnouts
> https://www.youtube.com/watch?v=bERjkSTYOdU
> 
> With a smaller 6.7" motor.


6.7 to 7.2". Not a huge difference. They have a Zilla 1K. And appears like sprocket ratio higher than 3, maybe up to 4. 

The other thing with burnouts is breaking free and then spinning tire on hot soft rubber. Zilla slams the current almost instantly. Soliton not so much. Big car drag race guys preferred Zilla over Sol for that reason.

I know you want to impress the chicks with burnouts, but really peeling and smoking just slows you down and makes you buy more tires.

major


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## Pota (Nov 25, 2017)

major said:


> 6.7 to 7.2". Not a huge difference. They have a Zilla 1K. And appears like sprocket ratio higher than 3, maybe up to 4.
> 
> The other thing with burnouts is breaking free and then spinning tire on hot soft rubber. Zilla slams the current almost instantly. Soliton not so much. Big car drag race guys preferred Zilla over Sol for that reason.
> 
> ...


I see 

You know of any 9" or some kinda forklift motor which is capable of giving me alot more torque?

Anyone selling Zilla btw ?

Im just impressed with how he does wheelie with those very wide tires, and got same motor as me.. He says it should be 500amp and runs 1.25:1.But maybe the controller delivers alot more :S i dont know


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## electro wrks (Mar 5, 2012)

Pota said:


> FINALY Major and the rest
> 
> I have done the torque test! Strapped the wheels to the ground
> 
> ...



What is your voltage drop at the motor terminals. Also are you measuring the current with the clamp-on attached to the leads going to the motor from the controller or from the battery to the controller?


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## Pota (Nov 25, 2017)

electro wrks said:


> Pota said:
> 
> 
> > FINALY Major and the rest
> ...


1.3v. From 48.2v. Both amp and volt measured at the motor leads, not battery.


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## major (Apr 4, 2008)

Pota said:


> 1.3v. From 48.2v. Both amp and volt measured at the motor leads, not battery.


46.9 volts and 320 amps ( both measured at the motor terminals) at stall (zero RPM) doesn't compute.


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## Pota (Nov 25, 2017)

major said:


> Pota said:
> 
> 
> > 1.3v. From 48.2v. Both amp and volt measured at the motor leads, not battery.
> ...


True. I'll do a New torque test reversert.

But major. If it gives me 7.5kilo lift at front at 600amp. With 1:1 ratio. What does 3:1 then? 22.5?
Still with me in it and 50kg at front then i need around 1400amp.
But how the H***L does dick wood with same motor and 500 amp and 1.25:1 flip the gokart with more weight than mine at front??
He would need like 2500+amp...


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## boekel (Nov 10, 2010)

Pota said:


> But how the H***L does dick wood with same motor and 500 amp and 1.25:1


where can you see or does he state the 1:1.25 ratio? the only video's I found were more like 1:4 to 1:5

and if you have 48 volts at the motor terminals - and - 300A then indeed something is loose and you should be seeing things light up, cause that's 15 kW going somewhere...

shure the 48 volts weren't at the battery terminals?


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## Pota (Nov 25, 2017)

boekel said:


> Pota said:
> 
> 
> > But how the H***L does dick wood with same motor and 500 amp and 1.25:1
> ...


This is 1.16:1 ratio
https://www.youtube.com/watch?v=XsutcOljO7A

Wheelie with wider tires
https://youtu.be/BGwtqgN_7no

Same motor. And paul and sabrina 500amp controller. It even weigh more. And he does insane burnouts and wheelie with wider tires.
My dont even burnout without me in it and smaller tires.

I have 600amp evnetics soliton jr. Peaking at 670amp

No. I measured the volt at the battery wires before the controller. Should i do it at the motor wires?


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## electro wrks (Mar 5, 2012)

If you are not accurate about the details of your set-up, then it makes it very difficult to provide help! And yes, it does matter a lot where the V and A are measured. It sounds like you need to do a lot more homework!


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## Pota (Nov 25, 2017)

electro wrks said:


> If you are not accurate about the details of your set-up, then it makes it very difficult to provide help! And yes, it does matter a lot where the V and A are measured. It sounds like you need to do a lot more homework!


I ofc measured the amp from the motor. The only thing i dident do right was the volt. But its by mistake i learn more


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## major (Apr 4, 2008)

Looks like a large sprocket here. 

https://m.youtube.com/watch?v=FLDIPcGxsAA

Obviously not the same controller but basic kart might be same. How do you know his wheelie ratio? What is your kart speed (mph or km/hr) at 2500 RPM on motor?

major


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## Pota (Nov 25, 2017)

major said:


> Looks like a large sprocket here.
> 
> https://m.youtube.com/watch?v=FLDIPcGxsAA
> 
> ...


Hey Major,

This is his old kart. This has Alltrax controller, and smaller motor. Its ratio is 2.12 : 1. So yes thats correct for his older version.

He upgraded the Motor to Prestolite MTY4001. Paul and Sabrina 500amp controller and somewhat kinda larget battery pack. 
He is running between 1.25 : 1 and 1.16 : 1.
Here take a look at the upgraded version from about 2sec in. There you can see the sprocket. 
he is also stating the ratio in his video.

https://www.youtube.com/watch?v=UfcsmtBLqJ4 

Here. Read the comment from him.



https://www.youtube.com/watch?v=XsutcOljO7A


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## Pota (Nov 25, 2017)

You see Major?


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## major (Apr 4, 2008)

Pota said:


> You see Major?


Okay. Check my math, but isn't a, 1:1 ratio going to produce like 90 mph at 2500RPM. Think that's needed?

But hey. Your kart. Do what you want. And yep, 9 incher will give more torque per amp. Look up torque curve for WarP9. It's basically a lift truck motor made by Netgain.

major


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## Pota (Nov 25, 2017)

major said:


> Pota said:
> 
> 
> > You see Major?
> ...


Hehe you are pretty close. Around 78mph with 10.5" tire 🙂
Ill try change the gear ratio to 2.50:1. You think i will feel alot better torque instead of 2.22:1?


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