Differences between high end ESC's and cheap ones for Lehner motors?

[dmitry100]

Differences between high end ESC's and cheap ones for Lehner motors?

Ok so yesterday I ran a saw pass with my HPR99... after what I thought was a successful full pass... the second I let go of throttle — the boat went airborne ... made a skip on the water and then with about 5 feet of air time it made an upside down belly flop (hatch first) on the grass.

There was no evident damage except a small hairline crack on the hatch. But what was weird was that it looked like my strut and flex became separated and busted out the bearing in the process. It was running normal until throttle release... could it have happened afterwards? My rudder was bend to the point that it got a big dent from prop.

Its a real pain not knowing how fast it went because my GPS seems to be getting signal blocked by the cf hatch even though i always thought HPR made them with gps in mind.

So now I’m thinking whether to buy a small gps antenna that I can mount outside (by driving a tiny hole to pass wire thru) and attach to my gps inside. Because I know I’ll be fishing for the gps in water every time I make a pass with crash. Have any of you did anything like this?

[TRUCKPULL]

At speed - when you back off of the throttle - the prop is now turning the flex shaft the wrong way .

Larry

[dmitry100]

so a more gradual release of throttle is always a good idea then

[srislash]

so a more gradual release of throttle is always a good idea then

Yup

[eXoNerated]

No one may be here but if you are. Look at this new 40KW controller that does 400 continuous and 600 max at 20s lipo . Look at the footprint. It has balls as it can also be used for EV. It will run high pole count NEU or Lehner motor quite well and efficiently. The processing speed of the other drives cannot remotely compare nor are they as power dense. They are $1200.00 a piece though and the before mentioned are huge in comparison. You should add some ceramics to compliment such large bulk electrolytic because they have real difficult time dealing with the faster transient esp with such long barrels to fill if you plan to go that route. High end drive$ that wont drive all the motors doesn't seem right does it? Another problem with these drives can be motors with very short coils because they have increasingly lower induction and the way to get out of this problem u have 3 options. One is lowering the bus voltage , 2 is adding load, or 3 raising the PWM. So a boater picks which on a boat with the prop he already wants? Raising the pwm of course .The MGM cannot match this drive as it has 3 times the pwm capability. MGM is also not user friendly. If you make mistake in setup and and burn it many people had to pay for repair.

I have 2 castle 200 Ice hv v2s and they have been flawless for me but still the cant turn high poles counts beyond the limit of the processors. The reason they do better with all motors is they run a 6 step BLDC algorithm not a sinus one which takes more processor speed. It isnt just the poles that create the switching issues the type of commutation algorithm the use plays a huge part in it. Some designers got around this by using a fast acting logic array in addition freeing the processor to do more work in commutation. A sinus drive works best with a sinus motor and a bldc drive works best with a BLDC motor.Sinus setups are cleaner a by a few % more efficient at the low end but at the high end theres not much difference. Some of the most sophisticated drives right now are actually the 30 dollar BLheli 32 inverters you can buy anywhere. If you team its logic with a custom bridge you'd really have something. Low pass and notch filtering will pay you dividends. More poles make more torque so its a matter of choice not quality between the two motors. Lehner may have a slight advantage in rotor design with sliced rotors and CF sleeves but the NEU is still a very good motor with a winding factor of one. They also have released a TL4 rotor at the request of 5FD pilots that can turn more rpm. All the wire except the end turn go toward making torque.The Lehner eliminate many of it problems simply by being a 2 pole. At that its working harmonic is the fundamental 2 pole. In a NEU the working harmonic is the 4th. That changes things as far as the rotor loss is concerned.

I'm in cooperation with Phds at ABB's corporate research center in Raleigh NC at NC State.
Were working on the newest winds that will lower the BEMF THD on a high pole count external rotor FSCW machines.

You can observe here that running a BLDC Inverter with Sinus motor or Sinus inverter with BLDC motor only creates more ripple.
This is another way matching can give better performance.