Changing the ebike rear rim connection to delta

[Ahmet0304]

I want to speed up my ebike rear rim please help?
My idea is to convert the star connection to delta but I don't know how

 

[SafeDiscDancing]

I want to speed up my ebike rear rim please help?
My idea is to convert the star connection to delta but I don't know how

Star.... do you mean Wye?

The opposite of Delta is usually called Wye.

And first you need to verify your existing motor is actually in the Wye configuration so that you can switch to Delta.

If you take Wye and multiply by the square root of three (about 1.7) you get Delta speed.

But if it is already in Delta you are out of luck unless you want to do a full rewind.

 

[larsb]

Star and wye are both pretty well known nomenclature in the electric world.. :wink:

You can see the difference in connection here:
http://www.bavaria-direct.co.za/info/

 

[SafeDiscDancing]

Star and wye are both pretty well known nomenclature in the electric world.. :wink:

Yeah I know... at times I forget which type Star is.... Delta or Wye.

I guess Star means Wye because it kinda looks like a star shape with a center.

Habits die hard I guess... Wye is easier for me to remember and I have actually done a Delta to Wye conversion once.

If you have Delta they tend to mingle all the wires together so it's a very slow process to carefully check each strand to be certain it matches the other end.

Use a ohm meter to verify each strand.

 

[Ahmet0304]

hello this is my rim but i don't know the connection type i want to increase it to max speed help

 

[Ahmet0304]

hello i have an ebike-a i will leave my rear wheel and controller photos i want to increase this ebike to its maximum speed help infineon i have a controller

 

[SafeDiscDancing]

It's hard to tell for sure in that image.

The white stuff covering the three phase wires are to prevent them from accidentially shorting against each other.

Notice the lower area in that image where it "looks" like maybe, just maybe you are in luck and this is Star or as I prefer to say Wye connected.

You need to look more closely and see what is going on there.

But if that wire is ultimately part of the three phase wires (that have the white heat shield) then all they are doing is snaking the exit point around to one location.

So I still cannot say for sure.

Look at the end of that Star (Wye) wire and see if that's a "crimped" end. If so I'd say "yes" you have a project to do.

Your next step would be to remove the "crimp" and then we get to the Delta reconnection which means your six wires (three white shielded and the rest "crimped") need to be combined in a way where you will need to also merge everything down to just three.

If you have a "crimp" then that's the "Neutral" as in the image.

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One concern. If you go from Star (Wye) to Delta that will increase your no load top speed by 1.7.

Can your controller handle the increased "Electrical Rotations Per Minute" ERPM?

Hub motors spin slowly but they do it with lot's of magnets and coils so the controller has to switch a lot.

You might find that you don't get the full 1.7 increase because the controller cannot switch fast enough.

 

[E-HP]

What is the max speed when you are riding, and what is the max speed with the wheel under no load (lifted off the ground)?

 

[Ahmet0304]

Kontrolörum infineon

 

[Ahmet0304]

what should I do

 

[E-HP]

how big is your battery?

 

[SafeDiscDancing]

how big is your battery?

Yeah.... you know the "easy way" is to add more voltage.

So a 24 volt battery will spin up to (say) 15 mph and a 48 volt battery would take that to 30 mph.

Rather than possibly destroying something you might just do that.

I just cannot see well enough to be confident of telling you to start cutting things.

 

[E-HP]

how big is your battery?

Yeah.... you know the "easy way" is to add more voltage.

So a 24 volt battery will spin up to (say) 15 mph and a 48 volt battery would take that to 30 mph.

Rather than possibly destroying something you might just do that.

I just cannot see well enough to be confident of telling you to start cutting things.

That would be the best and least complicated route. Seems like the OP wants to just switch from Wye to Delta, and not have a mechanism, for switching back and forth. If that's the case, the battery and controller have to handle the current from a dead stop. By starting in Wye, then switching to Delta once the motor is going, you avoid blowing up the controller, at least that's my understanding.

 

[SafeDiscDancing]

By starting in Wye, then switching to Delta once the motor is going, you avoid blowing up the controller, at least that's my understanding.

No, he just wants a higher kV by 1.7 and run it permanently.

The pictures he is posting are focusing on the three phase wires and the sensors.

We need an up close picture of if there is a Wye (Star) "crimp" that could be separated.

He just isn't focused on the right thing to look at.

This was the best picture of those he posted.

See at the very bottom what might be a Wye (Star) "crimp"? (sort of gray in color with grooves)

If it is then he needs to wiggle that out a bit and get a closeup so we can advise him to dive into it.

It looks like some high heat string is holding it in place. He needs to cut the string and pull it out.

 

[E-HP]

By starting in Wye, then switching to Delta once the motor is going, you avoid blowing up the controller, at least that's my understanding.

No, he just wants a higher kV by 1.7 and run it permanently.

The pictures he is posting are focusing on the three phase wires and the sensors.

We need an up close picture of if there is a Wye (Star) "crimp" that could be separated.

He just isn't focused on the right thing to look at.

This was the best picture of those he posted.

See at the very bottom what might be a Wye (Star) "crimp"? (sort of gray in color with grooves)

If it is then he needs to wiggle that out a bit and get a closeup so we can advise him to dive into it.

It looks like some high heat string is holding it in place. He needs to cut the string and pull it out.

I was looking at some stats online, and it looks like the starting current from the delta vs wye is like 5X, so it seems that the controller needs to be pretty robust if no switching is involved.

 

[bingosunnoon]

It's probably already been discussed but here's a thought. A revision from Y to Delta changes the voltage coefficient. Check to see if your new winding puts out more than the battery can take. More as in voltage. AKA Headroom. Applies to DD motors only.

 

[SafeDiscDancing]

I was looking at some stats online, and it looks like the starting current from the delta vs wye is like 5X, so it seems that the controller needs to be pretty robust if no switching is involved.

Does NOT apply here.

That's for big industrial motors needing a soft start and that's coming off the "raw" A/C power line.

This is DC power and all controllers have Battery Current Limiting.

So no... in fact... since you in effect go from one kV to another 1.7 higher the current carrying capacity goes up.

If anything he will be tweaking his controller with a higher Battery Current with a "cheat wire".

I do it underneath the shunt on the bottom of the board so I'm not messing with the defaut shunts directly.

Most of these controllers start as a default value of 35 amps or so, but with a three inch 22 AWG "cheat wire" you can get it up to 50 amps.

Best to start with a five inch wire and just gradually test it until it's the current you want.

-----------------------

Again... we need to see that "crimped" wire by cutting those strings and exposing exactly what is there.

I does look like Wye (Star) but we need confirmation so we don't assist this guy in destroying his hub motor.

The more I study that picture the more I think that is a "crimp".

 

[Ahmet0304]

close up photos

 

[SafeDiscDancing]

close up photos

Let me be 100% clear.

I want a closeup of the "crimp" and ideally after you cut the strings that keep it in place and pull it out a little.

It's possible you might be better off by just not destroying what you already have.

 

[Ahmet0304]

Help

 

[Ianhill]

Star to delta will increase kv by a factor of 1.7 but you wont find an increase in current at all it will pull less and you will feel it too theres less starting torque as a result becuase theres more resistance in line thats common sence as the motor spins up and bemf forms another problem with the kv increase shows itself now the i2r losses are worse at higher rpm too and the motor wants to spin fast but may not have the torque to do so.

Whenever we calculate speed and then in real world get a much lower number its likely theres not enough torque avaliable at given rpm for load, that large disparitie means the motor is working max and will get hot.

Basically to push a motor harder with current means it needs some additional cooling and to push it with rpm means the laminations etc need to cope with the increased frequency or if delta to wye swapping have a large torque defist to be able to sacrifice the startinf torque for addtional speed and most hubs are wired to the sweet spot from factory it be dull to sell my product and have john wayne make it better that would make my whole enterprise mickey mouse.

 

[Ianhill]

To be fair improvements can be made on a motor but normally it comes with a rewind to help copperfill then there termination change to star from wye to get more rpm and the copper fill help fill in the low end torque loss but the motors lamination steel thickness has the final word on how fast a motor can spin and in turn its heat build up with frequency increase

 

[SafeDiscDancing]

Help

Okay great you found the "crimp" and separated the three Wye (Star) ends.

Success !!!

On to the next Step.

You now need a voltmeter than can be set to read resistance in Ohms.

Discover which of the phase wires matches the end wires... use a piece of tape and write down which is which and put it onto the end wire.

Once you know how they are related you can move to actually connecting in Delta.

This will be easy if you just remain calm and do these necessary tests.

You are looking for very low resistance that is almost zero on a correct match.

Realize also that to achieve a Delta configuration those phase wires will need to be worked on too and along the way there is a chance that the default motor rotational direction gets messed up. But do not worry that will be easy to fix by swapping wires.

 

[SafeDiscDancing]

Look carefully at the upper left Star connection wiring.

You have the three phase wires in different colors. Then you have what was the "crimp" creating a three way connection.

Next look at where you want to go.

Assume you have CORRECTLY identified which phase wire matches the end wire.

Now simply realize all you need to do is connect the right end wire to the appropriate phase wire and you should be done.

It might be a good idea to simply test it with a hand wound connection just to make sure everything is okay.

Then once you are sure it is right you solder the necessary connections and hopefully get some high temperature cloth shielding like on the phase wires to keep it insulated.

You might need to buy some of that insulation cloth... I bought some on my rewind and it was a few bucks.

-----------------

It also might be a good idea to actually label your three coils:

U1 ---> U2
V1 ---> V2
W1 --> W2

...that way you can look at the diagram and see where the letter number combinations line up.

Notice they show the relationships as shifted to make it seem really easy.

All your existing phase wires are assumed to be U1, V1, W1 and your "crimped" ends are U2, V2, W2.

You need to think ten times and then act once.

Patience.

This is a heavy mental exercise if you aren't used to thinking along these lines.