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Jun 10, 2020, 12:57 PM
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Quote:
Originally Posted by p901P901
That's a tough one bartk.
Look at the way Lehner terminates their motors. Maybe this would work?
Looks good

If I would want to do something like that I need to mill a new hub, because the current one has only one big hole
and it also needs to support the bell support bearing

I removed the new winding, and the purple protection plate, printed a new one it is is already glued on and it is drying
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Jun 10, 2020, 05:29 PM
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p901P901's Avatar
Yes that would make sense to remake the end bell.

The motor I made did not use an end bell instead it just used a tube as a support for the bearings and a mounting support. Since the back is open. it could allow many types of terminations. It just another way of building motors.

xF 84 6 cell test (1 min 54 sec)


Crossing winding pairs across the stator is a pain with large gauge wires. Separating the pairs into groups and then terminating them in the back makes it allot easier. Looks like that is what Lehner has done.
Jun 11, 2020, 09:12 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
Nice motor and prop.


Wow It's a good thing your outrunner will reduce prop rpm
From
Republic_XF-84H_Thunderscreech (wikipedia)

Quote:
Originally Posted by wikipedia
...
Noise
The XF-84H was almost certainly the loudest aircraft ever built, earning the nickname "Thunderscreech" as well as the "Mighty Ear Banger".[16] On the ground "run ups", the prototypes could reportedly be heard 25 miles (40 km) away.[17] Unlike standard propellers that turn at subsonic speeds, the outer 2430 inches (6176 cm) of the blades on the XF-84H's propeller traveled faster than the speed of sound even at idle thrust, producing a continuous visible sonic boom that radiated laterally from the propellers for hundreds of yards. The shock wave was actually powerful enough to knock a man down; an unfortunate crew chief who was inside a nearby C-47 was severely incapacitated during a 30-minute ground run.[17] Coupled with the already considerable noise from the subsonic aspect of the propeller and the T40's dual turbine sections, the aircraft was notorious for inducing severe nausea and headaches among ground crews.[11] In one report, a Republic engineer suffered a seizure after close range exposure to the shock waves emanating from a powered-up XF-84H.[18]

The pervasive noise also severely disrupted operations in the Edwards AFB control tower by risking vibration damage to sensitive components and forcing air traffic personnel to communicate with the XF-84H's crew on the flight line by light signals. After numerous complaints, the Air Force Flight Test Center directed Republic to tow the aircraft out on Rogers Dry Lake, far from the flight line, before running up its engine.[14] The test program did not proceed further than the manufacturer's Phase I proving flights; consequently, no USAF test pilots flew the XF-84H. With the likelihood that the engine and equipment failures coupled with the inability to reach design speeds and subsequent instability experienced were insurmountable problems, the USAF cancelled the program in September 1956.[19]
...
Last edited by Ron van Sommeren; Jun 11, 2020 at 09:43 AM.
Jun 11, 2020, 09:18 AM
Ronaldo Nogueira
ronaldopn's Avatar
Thread OP
Quote:
Originally Posted by p901P901
Yes that would make sense to remake the end bell.

The motor I made did not use an end bell instead it just used a tube as a support for the bearings and a mounting support. Since the back is open. it could allow many types of terminations. It just another way of building motors.

https://www.youtube.com/watch?v=qN5BALOYPVk

Crossing winding pairs across the stator is a pain with large gauge wires. Separating the pairs into groups and then terminating them in the back makes it allot easier. Looks like that is what Lehner has done.
Awesome!
Bartk, in case you plane to run on 12S, why don't you wind with 2 part single layer scheme (hpLRK)? No transitions to complicate or waste space.
Ronaldo
Jun 11, 2020, 10:43 AM
Registered User
Quote:
Originally Posted by ronaldopn
Awesome!
Bartk, in case you plane to run on 12S, why don't you wind with 2 part single layer scheme (hpLRK)? No transitions to complicate or waste space.
Ronaldo
the problem I see ( had it already with the Tomcat ) is that the lrk takes a lot of space on the front and back and it is then difficult to make the connections
second is that it is very difficult to do it needly, and then we get an inefficient wind with less cooling.
I now do the wind with a 43% increase of fill and I can do it with 60% with 1.32mm wire

I do it now with 1.25mm and it is easy to do, I only have to wait with the last 4 turns ( second layer ) after I already wind the next tooth

Her you can see that I already did the 5th tooth and I still need to finish the 4th tooth.
I have to say I need to use some CA or epoxy to keep the top turns in place


And here I finished the 4th tooth
Jun 11, 2020, 11:03 AM
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p901P901's Avatar
Ron.:
My XF-84 does not make the same noise as the real one. But it sure has plenty of power.
Jun 11, 2020, 11:19 AM
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p901P901's Avatar
bartk:

Had the same loose wire winding my motor. Using some spray on motor varnish works great to prevent the wires from rubbing against each other. The other problem was the wires were popping out the tops of the slots, this was also fixed by the varnish. The varnish is like spray paint and when used in heavy coats it will flow in between the wires and bond them together. https://www.sprayon.com/product/el60...ating-varnish/.

Also magnet wires do have a minimum bend radius. It prevents kinking the wire, damaging the coating and increase "frequency resistance". I would think slot mutual inductance would be far more important than the winding that are looped around each tooth.
Last edited by p901P901; Jun 11, 2020 at 05:05 PM.
Jul 04, 2020, 04:29 AM
Registered User
I have tried to find motor varnish, but it is real not easy to buy.
Really would like to have it because I sometime damage a wire a little bit.
would be nice to patch it up.



But here is the end result of a really full Rotomax 50cc
more the 43% increase in copper YYYY terminated still needs to be done :-)

Jul 04, 2020, 05:04 AM
Registered User
p901P901's Avatar
Quote:
Originally Posted by bartk
I have tried to find motor varnish, but it is real not easy to buy.
Really would like to have it because I sometime damage a wire a little bit.
would be nice to patch it up.

Nice rewind.
ya its always a concern that a wire insulation was accidentally nicked. If so then there may be shorts related to frequency or voltage spikes. Its also nice that it bonds the windings together and eliminates insulation wearing from thermal expansion.

Just about any GLPT Insulating Varnish will work https://www.amazon.com/Waldom-10-900.../dp/B00JFKU6JQ. This is the stuff I use https://www.amazon.com/Red-Insulatin...PJFB241C19QF9P But I prefer clear.
Jul 04, 2020, 10:06 AM
Registered User
The spray can I can buy in amazon.com for about 17 dollars, and shipping costs are 183 dollars, no typo
I want the red transparent varnish and the other one is not , but total cost 180 dollar for 2 oz ( about 60 millilitres )

All 12 phase of the motor produce a proper sinus so it is OK to put it together.
I will wait, I finally ordered the enameled stripper.

Will start Measuring the Xpower motors
Jul 06, 2020, 04:19 PM
Registered User
First Kv measurements
203kv = 2360 rpm with 11.6 volts and 3.2A
Spot on same as the Tomcat G50CC
I only realist now that the axle is bend.
Need to see if I can fix that, or if it is only the top part of the axle , else I need to buy another one.

Will use a micro meter to check if the bell is strait.
Last edited by bartk; Jul 06, 2020 at 04:26 PM.
Jul 08, 2020, 07:22 PM
Registered User

Question


Is FLAT / rectangular wire available to get a easier copper fill ? Huge transformers use flat / rectangular windings.
Jul 09, 2020, 02:00 AM
Registered User
Skylar's Avatar
Quote:
Originally Posted by bartk
First Kv measurements
203kv = 2360 rpm with 11.6 volts and 3.2A
Spot on same as the Tomcat G50CC
That's a rather inaccurate way of measuring Kv. ESC losses are not taken into account and might affect the calculation.

More accurate ways to determine Kv: www.bavaria-direct.co.za/constants/#Kv
Jul 09, 2020, 04:43 AM
Registered User
Quote:
Originally Posted by Skylar
That's a rather inaccurate way of measuring Kv. ESC losses are not taken into account and might affect the calculation.

More accurate ways to determine Kv: www.bavaria-direct.co.za/constants/#Kv
This is how I see it, ( theory vs Practical )
How much loss do you think an 100A esc has when 3.2 amps are runs through it ? less then 0.1 volt max
Oke 2360/(11.6 -0.1) = 205 ( 1.5 kv difference ) that is less then 1% difference, I won't notice that.

And btw, I always use the same ESC for kv measurements, so this works 100% accurate for me.
Jul 10, 2020, 02:01 AM
Registered User
Skylar's Avatar
Quote:
Originally Posted by bartk
This is how I see it, ( theory vs Practical )
How much loss do you think an 100A esc has when 3.2 amps are runs through it ? less then 0.1 volt max
Oke 2360/(11.6 -0.1) = 205 ( 1.5 kv difference ) that is less then 1% difference, I won't notice that.

And btw, I always use the same ESC for kv measurements, so this works 100% accurate for me.
You have a good point there. In that case, comparisons should be in the ball park. Btw, how do you measure no-load RPM?


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