Triple Rewind of Unite 500W Motor

[Fuzzo]

The marathon is always a popular race at the Olympics.

 

[safe]

:helmet: Let's move the racing related discussions over to this thread:

http://www.motoredbikes.com/showthread.php?t=20735

 

[duivendyk]

Racing as not just about "passionate" ****-for-leather-****-the-torpedos charging about.Drag racing might be, but not road racing,that is about all the aspects of racing:strategy,riding skill,conserving fuel,making your engine (battery) last etc.I think rationing battery energy is a good rationale,for a MB (power assist) race.Otherwise run a Electric MC race.

 

[safe]

Try to move this racing stuff over to the other thread.

I stand by my preference because a battery limited race will tend to take the "sport" out of "sport riding".

There could be both types... one for the "wild folks" that want speed and another for those that want to go slow and fiddle with their efficiency. I just think that a race that is primarily about efficiency is rather dull. (my own opinion)

But let's move the discussion over to the other thread... this is the rewinding thread...

 

[storm1]

I have a 750w and a 350w motor, I pulled them both apart last night to see the differences, the 350 has a shorter length stator and less turns, Safe do you know if the 500w motors have the same stator as the 750w/1000w motors?

 

[safe]

The 500 watt motor has an iron core width of exactly 2". (the 750W/100W are wider)

The 750W/100W magnets are wider than the 500W, but they are proportional to the iron core width, so I've tried replacing the narrower with the wider and the difference is minimal. (the stronger magnets don't change much of anything)

So are you about to do a rewind?

Fill us in on your plans... do you know about the "Rewind Calculator"?

http://www.motoredbikes.com/showthread.php?t=19082&page=14

...if you plan to do a rewind expect to do it slowly and carefully. Don't try to rush through it because you need to do it in a very relaxed manner so that you don't make mistakes. The mind numbing repetitiveness of rewinds can be hard to handle for a lot of people.

(pretend you are Forrest Gump and you are fine)

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If that's a 350 watt motor and it's 2" wide then that's the same as the 500 watt motor. Hmmmmm... I managed to get 1400 watts of power out of mine after a rewind and if the cores are the same you could do the same with the 350 watt.

So in a bizarre twist it might be possible to get 1400 watts out of a 350 watt motor.

 

[storm1]

By width you mean length don't you? Running parralell with the shaft is what I call the length of the cylinder, so the width of the magnets wraps around the core and the thickness of the magnets can determine the airgap. So you replaced magnets with longer magnets on a short core correct? The thickness remained the same as did the width?, I feel we could fit a few more turns on the 750w motor but why would you stop at two or three winds and not do four or five?

 

[storm1]

BTW do you know what the differences are between the 750w and the 1000w?

 

[safe]

By width you mean length don't you?

Correct, the 500 watt iron core is "lengthwise parallel" exactly 2". I tried swapping the shells between motors and it doesn't have much effect.

I feel we could fit a few more turns on the 750w motor but why would you stop at two or three winds and not do four or five?

There is wire thickness and number of winds. You end up with a table of values to pick from. (use the "Rewind Calculator" tool) If the number of turns per wind gets too low then the no load speed (for a given rpm) can get too high.

The maximum realistic rpm before the brushes stop being efficient is about 5500 rpm. (above that and the motor loses power at the higher rpm)

You could do more winds and then use thinner wire. They have even in the past built special prepackaged stranded magnetic wire in order to increase the Litz Effect and get more current flow. However, all this stuff does have some level of diminishing returns. (they even sell square magnet wire in order to increase the packing density)

In most cases you want either a Single (good starting torque) or a Double (more power up top) and in the extreme cases use a Triple. And I have to stress that the whole goal here is to create a CUSTOM fit for your needs. Just rewinding blindly isn't going to help you much, you need to have specific goals in mind and then pick the rewind that matches your needs.

 

[safe]

BTW do you know what the differences are between the 750w and the 1000w?

This is all I know: