My 4525 rewinding project

[Vinger]

Ralph, just got a 4530 returned from Scorpion and it had the new shape fan and also a different stator to my older 4530LE. Scorpion is really on the ball with development.

[_Dekker]

Very interesting stuff Ralph, hopefully over time these improvements will come through in production motors.

Originally Posted by Vinger

Ralph, just got a 4530 returned from Scorpion and it had the new shape fan and also a different stator to my older 4530LE. Scorpion is really on the ball with development.

Scorpion indeed makes changes to their motors over time, I like that.
Reading your remark on the fan shape, I compared my own 4530 to the new 4525 rotor and indeed there is a difference: the holes in the 4525 rotor are wider.
I also really love the flexibility of Scorpion, look what they did on the 4525 kit they sent me

[powercroco]

so you got a special "signature" edition.

the last (and best) fan variation (only prototype) has 8 holes now.
and the main differennce you only can see from the inner side.

[_Dekker]

5+7 turns in 1.5mm.
This is the same number of turns as in post #39, but now with 1.5 in stead of 1.4mm wire.
For comparison:
12 turns 1.4mm: 18.4mm^2 copper surface
12 turns 1.5mm: 21.2mm^2 copper surface. Measures 9.3mOhm for YY.

Servo wire visible at the back is the Futaba telemetry temp sensor cable, the (stripped) sensor is epoxied on the windings.


Both motors are going to the same person setting up two Raptor G4 E720's, we are looking forward to comparing them.

[ZuvieleTeile]

Originally Posted by _Dekker

5+7 turns in 1.5mm.
This is the same number of turns as in post #39, but now with 1.5 in stead of 1.4mm wire.
For comparison:
12 turns 1.4mm: 18.4mm^2 copper surface
12 turns 1.5mm: 21.2mm^2 copper surface

Both motors are going to the same person setting up two Raptor G4 E720's, we are looking forward to comparing them.

Hey Bert,
is your guy able to log some data? Would be interesting to see the difference in those two windings.
Can you feed the data into DC?

[Laurens]

I am using a IISI-RC telemetry and data logging system, so I'm definatly able to provide data on both motors.

The 1.4mm wind motor is already really powerfull, but still I'm interested to see what differences I will notice. So far I'm not sure if I'll use 2 different ESC's or not though, maybe that will make a big difference too.

[ZuvieleTeile]

Thanks Laurens,
would be nice to have the data for the second motor with the same ESC . . .
But I don't want to be pushy.

[Laurens]

I can always swap them in a later stage. Should be interesting, but first I need a lot of data from the ESC thats powering them in the first couple of weeks.

[_Dekker]

Finished.





Meanwhile I also started doing back-EMF measurements to see what the differences are between motors, before and after rewind. This is for this rewound 4525:

[HeliFX]

Dekker

interested in learn more on how and what your using to measure the back EMF.

I take it your using some sort of scope . what model / make is your scope and is it cheap ?

Originally Posted by _Dekker

Finished.





Meanwhile I also started doing back-EMF measurements to see what the differences are between motors, before and after rewind. This is for this rewound 4525:

[_Dekker]

Originally Posted by HeliFX

Dekker

interested in learn more on how and what your using to measure the back EMF.

I take it your using some sort of scope . what model / make is your scope and is it cheap ?

I'm also still in the learning process, reading into this subject more.
Yes it's an oscilloscope, in this case a digital storage one from Tektronix. You can also use older analog scopes, these are a lot cheaper to get and measure just fine.

[HeliFX]

dekker that one expensive piece of equipment you have there unless you bought it used
I've done some general reading on the subject and yes still learning.

Originally Posted by _Dekker

I'm also still in the learning process, reading into this subject more.
Yes it's an oscilloscope, in this case a digital storage one from Tektronix. You can also use older analog scopes, these are a lot cheaper to get and measure just fine.

[DannyvG]

Originally Posted by _Dekker

Based on the n spec of the rewind: the original motor (5+6yy) must have 545rpm/V in stead of the advertised 520..

I just measured the kv of a brand new out of box 4525 ultimate and found a kv of 555rpm/volt with 22.5V and 18degree timing on yge.
Perhaps scorpion measures their kv on 5 degree timing.

[ZuvieleTeile]

Originally Posted by djamgils

I just measured the kv of a brand new out of box 4525 ultimate and found a kv of 555rpm/volt with 22.5V and 18degree timing on yge.
Perhaps scorpion measures their kv on 5 degree timing.

Yeah, they quote mostly data for 5 degr. timing.

[_Dekker]

The 5deg of scorpion should be much closer to YGE 18deg.
The higher Kv's that we measure is to me an indication of a lower quality motor: something in the magnetic design got worse, magnets, iron, stator, who knows.
Just like the first P800's that also measured too high Kv's and now are just about spot on.

[ZuvieleTeile]

Originally Posted by _Dekker

The 5deg of scorpion should be much closer to YGE 18deg.
The higher Kv's that we measure is to me an indication of a lower quality motor: something in the magnetic design got worse, magnets, iron, stator, who knows.
Just like the first P800's that also measured too high Kv's and now are just about spot on.

Yeah, could be.
Also not uniformly glued magnets can change the air gap, resulting in Kv variations from the stated ones.
I'd like to see more uniformity of the test equipment in the future.
I don't mind checking Kv of supplied motors with two different ESCs, but it is all time consuming. If the manufacturers would supply us with some more equipment data, we would be better off.
There will always be some minor variations in the 5 or 10 RpM range, but not 30+ like now.

[HeliFX]

higher timing will produce higher Kv value between 10 to 20 kv. ESC model and type also has an influence.

Powercroco has posted a chart of test he did when scorpion first started producing rewind motors. the three esc used was the YGE, JIVE and Scorpion each produced different Kv with a given timing.

scorpion does not mention which esc they used for there testing. I suspect its a custom test bed for workers to quickly test each new motor.

besides all motors should be tested at its base low value and limit the number of influencing variables that can shift the Kv.

Originally Posted by djamgils

I just measured the kv of a brand new out of box 4525 ultimate and found a kv of 555rpm/volt with 22.5V and 18degree timing on yge.
Perhaps scorpion measures their kv on 5 degree timing.

[_Dekker]

Got to rewind a stock 4525-520Kv Ultimate (YY termination).
This one has burnt windings in one phase, it seems this is something that can happen at random with the Scorpion 130A esc. Even though the windings looked like this, the owner had about 15 flights with it before he understood it's probably wise to do a rewind
The reason it still worked: All phases still measured 10mOhm and the motor still passed the 500V isolation test. 1000V isolation test was bad.
The original wind has no room for airflow and is soaked with epoxy.


Rewind was done with the same (1.4mm) wire and number (11) of turns. So it was nice to see how tight I could get it compared to the stock wind. We have airflow now:


Back:


Indeed as I suspected these 520 Ultimate motors have higher Kv than listed: I measured 549rpm/V (YGE 18deg setting)

[belcom]

Dekker, was it hard to remove the carrier? Was there a thin FG plate under the screw holes? Locktite or epoxy on this one? I would love to do mine just for the sake of opening up the slots for cooling. Mine has the same problem with epoxy all over the place and it gets quite very hot

[_Dekker]

Originally Posted by belcom

Dekker, was it hard to remove the carrier? Was there a thin FG plate under the screw holes? Locktite or epoxy on this one? I would love to do mine just for the sake of opening up the slots for cooling. Mine has the same problem with epoxy all over the place and it gets quite very hot

No not harder than any other Scorpion. Yes there is a thin fg plate. I used epoxy on this one.