Needs some motor knowledge

[acook50505]

Anyone have any links or reading material to explain the difference of motor windings. Thanks in advance.

[Erroneous]

https://forums.offshoreelectrics.com...2-Delta-or-Wye

[Speed3]

I have done a lot of research and testing with different size motors and different kV.

What I have found is if you have two motors similar in size example two 4082, one is y and one is d, the d wind motor will have greater torque.

Amp draw is affected by kV, prop load, friction in the drive and so on.

What I have found with amp draw, if you have two motors with different kv's one is 3000kv and other is 1500kv, the 3000kv motor will pull around 4 times more amps than the 1500kv motor if all things are equal with the exception of the motors. The size of the motor in my experience don't change that rule.

So the formula to calculate amp draw is higher kV divided by lower kV squared. (3000/1500) = 2, and 2x2= 4.

[acook50505]

I have done a lot of research and testing with different size motors and different kV.

What I have found is if you have two motors similar in size example two 4082, one is y and one is d, the d wind motor will have greater torque.

Amp draw is affected by kV, prop load, friction in the drive and so on.

What I have found with amp draw, if you have two motors with different kv's one is 3000kv and other is 1500kv, the 3000kv motor will pull around 4 times more amps than the 1500kv motor if all things are equal with the exception of the motors. The size of the motor in my experience don't change that rule.

So the formula to calculate amp draw is higher kV divided by lower kV squared. (3000/1500) = 2, and 2x2= 4.

That makes sense. So what does the different numbers in front of the Y or D mean like 1Y compared to 7Y and what is the affects of the different numbers?

[Speed3]

The different number is the number of turns.

Let say you have a 1y motor that has 2000kv, a 2y would have 1000kv.

The rule is if 1y is equal to 3000, then 3y would be 3000/3= 1000kv and 6y would be 3000/6= 500kv.

You will notice a given size motor has y wind and d wind, this is done to achieve the different kv's.

Example you have a 4y motor that have 1600kv, and you want to build a 2000kv motor, the y wind cannot create a 2000kv motor with same rotor and stator length so a d configuration will be used to create 2000kv.

You ever read about ampere turns. More ampere creates a stronger electromagnetic, well for this reason the d wind will have more amperes turns and that why they are more power than y.

Another thing you probably hear power is voltage x amps this is true in a sense. But what do say when I take a 1700kv motor, use a 445 prop run 4s lipo, and get 50mph in a give boat, While only pulling 40amps at 16v or 640watts input. Then you take a 2500 kv motor with the same prop and battery this pull 86 amps at 15.3v or 1315 watts input then the boat only goes 30mph. The 2500kv motor should be motor powerful but the speed shows how little it's power is compared to the 1700kv setup. I have experience these kind of this.

Anyone who know about power might tell you it takes about 2 horsepower to turn a x445 at 27000rpm. But I have electric setups that can turn that prop at those speed with less than 700watts. So something don't add up.

[Speed3]

I have a revolt that chase down a pro boat mystic that was doing 52 mph on GPS, The mystic turn off like 30 to 50 feet ahead of me and he was at full speed and my revolt from a stand still pick down the mystic in about 1.5 seconds, this revolt was covering a measured 150 feet in a little less than 1.5 seconds. And I was running a 4092 1730 kv leopard on 4s with a m545. I get a little over 4 minutes of runtime only slow down to turn. And I would put back 2700 mah back into the lipo.

[Speed3]

https://youtu.be/u9TcjuUXUz4

On the second past going east, the
revolt is the one that was at a stand still, the mystic that was doing 52 turn off in front, the impulse was coming at full throttle from behind. The impulse was doing 48 on GPS. Mind you the revolt was at a stand still, when the full throttle impulse pull up on me he was instantly left behind and the 52 mph mystic that turn off in front had the revolt right behind it in about less than 2seconds. The area where the revolt was at a stand still to when it was up on the mystic is over 150 feet.

[Speed3]

About 200 feet distance when it was up on the mystic, so look how fast it cover 200 feet from a stand still with a 1730 kv motor on 4s.

[Speed3]

https://youtu.be/qLijKb_Ar3g

Here is another video, this is an aqua craft wildcat with a 3660 tacon 2200 kv or feigao 540 L 11 turn equivalent, I was running a seaking 120 ESC, using a 4s lipo, spining a prop similar to the graupner
K42, the boat weight was 3 pound 1 ounche with everything including battery, it was pulling 30amps at full throttle and getting over 15volts under load and the boat was only doing around 25 to 28 mph max, and my revolt with the 1730 kV motor pulling around 40amps at full throttle and getting just under 16v underload was doing well over 50mph.

This is just an example of how you can sometime getting good output
power with not much input.

[ray schrauwen]

The higher kv motor might be deforming your plastic or composite prop. Try a metal prop.