My 4525 rewinding project

[HeliFX]

If the motor is used like the one in the photo. I'm sure the Loctite 648 would have an easier time breaking apart.
Its more a problem when the motor is brand new and not exposed to temp etc.

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

[Laurens]

Its 3 months later and I still haven't actually measured the differences between motors. Just by feel I'd say there isn't a lot of difference, but I haven't flown them back to back because Raptor #1 crashed before I completed Raptor #2. Also I've changed ESC's from Scorpion to Kontronik HeliJive, and last to YGE160HV.

I didn't like the HeliJive at all, I did have random cutting out issues without any fault indicated by the LED. Switching to YGE solved this. Then I found out that I have an 11T pinion instead of the 12T which I thought, that explains why I'm running a higher throttle % then it should for the 1950 rpm I like.

Raptor #1 is slowly getting repaired to fly again, but this crash was with a lot of bad luck. I guess because I worked on the head the day before, a link snapped causing a boomstrike. Packs where launched, tail was hit by the main rotor again, and it all fell onto the telemetry. On top of that I crashed above concrete, killing the pack and telemetry...

Updated about this 14% copper difference will follow ;-)

[prototype3a]

Does anyone know what a 4525 (ultimate) would weigh if it was rewound with just 1.15mm wire?

[omerco]

Hi all
Been wanting to finish this for long time:
https://www.helifreak.com/showpost.p...3&postcount=43

But than when i got some time off planing to start my X7's Ultimate 4525 has burned on me...this has been an unfortunate motor and a surprise on Scorpions side:
The stator was not glued properly to the holder, further more there was no securing anti-rotation pin. the way I discovered it was after 4-5 shut-downs and few sets of broken main blades the motor finally got stuck when the stator has reached the rotor. Before it was touch-no touch chafing the wires and shorting between them causing the shut-downs.

I have epoxied it back and fixed the wires with varnish and a couple of weeks later it burned, so here is the before:

According to scorpion (http://www.scorpionsystem.com/catalo...525_520_ult/):

Before:
Kv: Mesured! 525 rpm/V (Castle 120 + Scorpion 160)
Wire: 5+6 YY 1.4mm.
Copper surface: 16.94mm^2
R= 12 mOhm



After:
5+6T YY 1.5mm

Motor 1: 527rpm/V
Motor 2: 524rpm/V
Together: 528rpm/V (all with Scorpion 160A)

Io: 3.8A@44.7V
R: 9 mOhm

Copper surface: 19.44mm^2 (+14.7%)





Thank you Ralph for that - it was most helpfull:

https://www.helifreak.com/showpost.p...&postcount=181

more pictures are attached for whoever is interested.

[omerco]

Ok guys, and Ralph and Dekker especially, I need help here:

The above motor has burned 2 X Scorpion 160HV ESC's.

The first ESC was one I suspected to be problematic before therefore after it has burned I tested the motor thoroughly and found it to be perfact: 1000V test passed even when sticking the prob between the winds, KV is the same and I even tested both separate motors again.

So the conclusion was it is the ESC. I got a new one from a Scorpion sponsored guy here who was "buying" my story - and this one has burned today.

So now I have a problem: Is the motor the problem because it is defective? Or is the 1.5mm wire on the short 25mm stator causes amp spikes that kill the ESCs?

What more can I do to make sure the motor is fine?

omer

[prototype3a]

Can you test it at 2000v?

[omerco]

ן don’t have the means but maybe can get some. but from my knowledge if a motor passes 10X its voltage it should be fine, and this one passes 20X its voltage.

One thing I'm going to do is threw it in the oven for 80 deg (prox working temp) and test again.

[_Dekker]

Originally Posted by omerco

Ok guys, and Ralph and Dekker especially, I need help here:

The above motor has burned 2 X Scorpion 160HV ESC's.

The first ESC was one I suspected to be problematic before therefore after it has burned I tested the motor thoroughly and found it to be perfact: 1000V test passed even when sticking the prob between the winds, KV is the same and I even tested both separate motors again.

So the conclusion was it is the ESC. I got a new one from a Scorpion sponsored guy here who was "buying" my story - and this one has burned today.

So now I have a problem: Is the motor the problem because it is defective? Or is the 1.5mm wire on the short 25mm stator causes amp spikes that kill the ESCs?

What more can I do to make sure the motor is fine?

omer

Hi Omer,

Nothing as frustrating as a wind that does not work.
Things that come to mind:
Did you have a look at the magnets: not only spacing but also polarity?
Before termination of the motor:
-Do a 1000V test between all the individual wires.
-Measure the resistance of all the individual wires. If a loop is shorted this way you can find it. For this test it is handy to have all the wires the same length.
Last thing that comes to mind is that the waveform of the YY wind is slightly different (a bit sharper peaks) compared to the Delta wind, but I can hardly imagine that would pose a problem.
Perhaps the Scorp esc is very sensitive to "wrong" settings, but I do not know them enough to judge that. I did burn 2 (130's) myself on a 4225 YY wind on default settings. Before that the motor had run for >500 flights on a Jeti Mezon and Jive 80HV.

It is indeed also possible that the short is only created when the motor heats up. Most shorts occur on the outside turns which run over the hammer heads.

Bert

[omerco]

Originally Posted by _Dekker

Hi Omer,

Nothing as frustrating as a wind that does not work.
Things that come to mind:
Did you have a look at the magnets: not only spacing but also polarity? The can is the same can as before - the motor was working for 2 years before it burned and was rewinded. magnets pull looks fine.
Before termination of the motor:
-Do a 1000V test between all the individual wires. checked before the termination - between each 2 adjusent wires and between each and the stator. checked again now but without opening the termination only between it and the stator. all is fine
-Measure the resistance of all the individual wires. If a loop is shorted this way you can find it. For this test it is handy to have all the wires the same length. checked before the termination. after the ESC has burned I separated the 2 individual motors and tested KV of each to find it unchanged
Last thing that comes to mind is that the waveform of the YY wind is slightly different (a bit sharper peaks) compared to the Delta wind, but I can hardly imagine that would pose a problem.
Perhaps the Scorp esc is very sensitive to "wrong" settings, but I do not know them enough to judge that. I did burn 2 (130's) myself on a 4225 YY wind on default settings. Before that the motor had run for >500 flights on a Jeti Mezon and Jive 80HV.

It is indeed also possible that the short is only created when the motor heats up. Most shorts occur on the outside turns which run over the hammer heads. I don't have any turns running on the sharp hammer heads. I have already seen motor which short only when hot and that is part of my suspicion. I will try to test it after it was in the oven but I don't know if that will give good reference.
Bert

Hi Bert thank you for your reply. answers inline. the main question is indeed if this is the ESC not handling the motor or is the motor the problem?

The original motor is also YY terminated so that could hardly be the problem, question is if maybe the 1.5mm causes too much stress on the ESC. that motor (Ultimate) is known to have high AMP spikes with the original wind so maybe the 1.5mm just needs a more resilient ESC?

BUT HOW TO DETERMINE THE MOTOR IS FINE?? all tests seam to pass.

Thank's
Omer

EDIT: I now thought of that I can still check each coil's resistance again between the start connection and each phase. I will do so.

[_Dekker]

Hi,

You say you don't have any turns running on the sharp hammer heads. But what about these in the attached pic?
With 1.5mm wire and original plates it is not that difficult to cut through the isolation.
It is the winder that develops the "feel" to get that right so I cannot comment on that.
If you are 100% sure the 1000V measurement equipment performs as it should I rest my case
I would be hesitant to put the stator in the oven: they are often very badly regulated. I would just clamp the probes down and push on the windings (at the red circles) while measuring with for instance a wood piece.
Did you use a Scorpion esc on the original motor too?

[HeliFX]

did u check each group with a 1000v as you build or before the ends where terminated ?

then checked again once motor was completed one probe on shaft and the other on stator !

[omerco]

Bert

Ok that I have - I thought you meant the ones seen in your "extreme" winding.
I have a temp sensor glues to the windings (learned from you ) so I have no problem to regulate the heat to 80 deg - but i will check it also the way you recommended.

Thank you, again!
Omer

[omerco]

Originally Posted by HeliFX

did u check each group with a 1000v as you build or before the ends where terminated ?

then checked again once motor was completed one probe on shaft and the other on stator !

Yes - I test with 1000 few times during the wind of each coil (sometimes you short it at the first tooth so there is no need to finish and then discover it...) and once the coil is finished I test between it, the adjacent one and the stator.
After I finish all 6 coils I check again between each coil and the 2 adjacent ones and the stator.

Only after I verify that I terminate the motor and finally test again.

But even now the motor passes 1000V test. I will press on the windings to see if I can find a problem somewhere, as Bert suggested.

[omerco]

Bert
1000V test, clamped all the time, while pressing on the coils (all the "problematic" point and everywhere else I could) - passed.

Motor is in the oven now...

[omerco]

Ok I heated the motor to 90 deg:
1000V did show a slight jump on the scale and went back to zero. no beeping.

So what do you think?

[omerco]

So? Anybody? I'm a bit lost withnthismcase and would be happy for your professional opinion before I disarm the motor, or burn another ESC...

[omerco]

Update Since last:
I got back a week ago and yesterday have found the time to do some testing on the motor without disarming it (I.E. still terminated. I just separated the pair on the phases):

1.heated the motor to 90 deg and performed 1000V test again for each separate motor - between the 2 motors and between them and stator.

2. As per Bert's recommendation I measured the IR of all the coils again. This was done while the motor was still around 80-90 degrees. IR was found to be exactly the same and As expected (to my understanding this doesn't say there is no "leak" between 2 adjacent coils).

3. Last - heated the motor to 130 Deg and 1000V tested again, while pressing on all the coils and corners.

All tests passed. the max I could see is a slight jump on the meger when placing the second prob and back to Zero. couldn't get it to beep no mater what I did.

MY PROBLEM NOW:
I have a brand new YGE 160A which I'm afraid to burn the same way the 2 Scorpions did

[powercroco]

so you havetested every thing someone could test.

there is no other way anymore, than try it.

[omerco]

I'm trying to get a 12T SX wide pinion to fit it to my 690SX which is more tolerant to shutdowns (better auto-rotations). Then I have either a Castle 120HV or a YEP 120HV.

Lets see what happens

[jamage]

omerco, did you consider if the spike you saw in the meter might be something the esc sees as the motor cycles, think that the spike will also appear to the esc in some form of impedance or short. What did the coil test spike read when it jumped?