Originally Posted by Christian Lucas

... my Holländisch is not that good ...

Ab Bericht #419
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Starting at message #419
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Met vriendelijke groeten Ron

For better understanding, I wrote this post for HeliFreak, but repost it here:

I recently wound two so called LRK/SPS motors as an experiment for someone.
Base is the Scorpion S-4020 stator.
The intention was to give both motors the same number of turns (14) with thickest possible wire, and giving them an n spec on both motors around 1000rpm/V.
Both motors are LRK/SPS wind but with a difference.

Motor 1:
This is a "regular" SPS, with a twist:
The teeth are wound alternately, as is common with this type of wind, but they are terminated DOUBLE DELTA. This means it will turn twice as fast as with normal delta termination.
This also means that 4 wires will exit the motor for each phase. The scheme:



Motor 2:
The wind starts off with a "normal" SPS, for example on the uneven teeth. These are done with 7 turns, using this scheme:



That makes partial motor A. After that the remaining even teeth are given the exact same wind, making partial motor B. So also in this motor there are now 14 wires in each slot.
Then both partial motors are terminated in delta and the wires are going outside SEPARATELY. This is important, since the partial motors are offset by 30 degrees and for this reason they cannot operate on one controller. So this wind MUST be operated with two controllers. That is why I gave the phase wires different colors to keep them apart.

In the end, both motors have 1.4mm wire and have equal fill percentage. Copper surface in each motor is 21,6mm^2.
Left is the first motor (double delta SPS), right motor 2 (the double SPS, parallel terminated):


Here the back side, they are lying the other way around by accident. So left is motor 2 and right is motor 1:

Hi Ron, Dekker,
thank for sharing this wireoption .Will be intresting how it workes .I have done the same in star conection .
@Dekker,
do you have the possibility to drive one motor and have a look with a osziloscope at the other motor .Would be intresting how the back emf will look like .How many influence will induce into the other coils. Over all ,congrats for this great work Dekker.

Originally Posted by Christian Lucas

Hi Ron, Dekker,
thank for sharing this wireoption .Will be intresting how it workes .I have done the same in star conection .
@Dekker,
do you have the possibility to drive one motor and have a look with a osziloscope at the other motor .Would be intresting how the back emf will look like .How many influence will induce into the other coils. Over all ,congrats for this great work Dekker.

Hi Christian,
I had the idea recently to get a scope for exactly this kind of measurement: to see what back emf looks like in various winds/wire thickness/stator shapes. But I was afraid it would end up collecting dust.
So no scope.
But maybe you are good at convincing me it is essential equipment

Originally Posted by Christian Lucas

Hi Ron, Dekker,
thank for sharing this wireoption .

My DD 13 wind LRK motor was the smoothest running LRK I ever had. I'm curious how the "Double LRK with 2 controllers" will work. I've been wanting to do that for so long... I'm really happy with Dekker's work, making my "dream" of a 200A LRK direct driving a big prop come one step closer again...

My 2 Scorpion 4020 7DD motors have arrived...:

Hello Dekker!
I would like to wind a motor for a friend's EDF what do you think of the double delta for the application? Also do you have a drawing for a double Wye termination? This way I could figure wind calculation for approx Kv with available wire space etc.
Thanks,
Tom