Novak HV4400 and 7XL BL Sensored System...

[maxxdude1234]

I think griffinRU mean it will be able to handle more cells after modifications. Presumeably he'd be chaning the FETs to much more powerful ones, and installing different capacitors, and maybe a few other things. I've seen some of his work with modified EVX's - and its all looks very well done!
I was merely asking what the current handling capabilities of the stock HV-maxx ESC were, because they must be quite high if it can handle the 7XL. Novak havn't released many specs to do with the HV-maxx controller, so I wondered if anyone knew?

[GriffinRU]

Originally Posted by maxxdude1234

I think griffinRU mean it will be able to handle more cells after modifications. Presumeably he'd be chaning the FETs to much more powerful ones, and installing different capacitors, and maybe a few other things. I've seen some of his work with modified EVX's - and its all looks very well done!
I was merely asking what the current handling capabilities of the stock HV-maxx ESC were, because they must be quite high if it can handle the 7XL. Novak havn't released many specs to do with the HV-maxx controller, so I wondered if anyone knew?

Thank You,

With proper cooling (stock fan works fine) up to 400A continuous per phase, 1000A peaks. Datasheet specs. But I will say 210A to be safe. Two FET's (IRF3703) per phase 210A each, 2.8mOh Rdon

To sum this all - 1.73*210=363.3 average :)

Enough to move motor wires if timing wrong.
2 to 5 times more starting torque then same motor with sensoreless ESC.

Artur

P.S. In stock form ESC is pretty good, HV-motor sucks...

[Serum]

according to the datasheet it is limited to 70A, due to the TO220 package. (even at 25 degree celcius)

on 75 degree, the max current would be 175A, though it is limited to 70A by the housing.

[GriffinRU]

Originally Posted by Serum

according to the datasheet it is limited to 70A, due to the TO220 package. (even at 25 degree celcius)

on 75 degree, the max current would be 175A, though it is limited to 70A by the housing.

Thats true if you are on safe side...
There are some other limits as well, but at 300+A continious motor will meltdown :)
Key element is to keep FET's at 70-80C and the rest would be good.

But we are pushing limits here, right?

Even 70A*2*1.73 good current.

Artur

[RC-Monster Mike]

Neat idea, Artur. Very interesting indeed. :)

[GriffinRU]

Originally Posted by RC-Monster Mike

Neat idea, Artur. Very interesting indeed. :)

Thanks, Mike
I will keep updating on testing.
My camera will be back on Thursday, so I will add some pictures and know-how about setup. It is pretty strait forward but timing can be tricky.
Artur

P.S. How 66 spur with 18 pinion sounds with HV4400 and 7XL ...

[RC-Monster Mike]

Stock gearing is fine for the 7xl, Artur. I imagine the timing would be the tricky part. I look forward to your continued info on this little project.

your project definately has potential to be a great way to drive at low speeds and not have to worry about cogging.

[MetalMan]

This is a very interesting idea! A perfectly smooth sensorless motor... Who would have thought!?!? Besides the requirement of two motors, I'd be more than willing to test this out! It would be nice if Feigao brought out some sensorless motors compatible (in stock form) with the HV ESC!

[Dafni]

Very nice, Artur, very nice indeed!
I have never had a Novak, but would it be possible to open it up and isolate the sensor part? Or maybe at least get rid of the heavy magnet? Reducing rotating mass is always good.

As for your broken tranny gears, I assume you keep shredding idlers, right? If yes, just replace it with mikes steel idlers and you will not have to worry about your tranny anymore. And a strobe slipper says goodbye to molten spurs, too.
You definitely can get the driveline up to the job with some minor investments.

On a 7XL you can also try 18/66 gearing. On my revo (and 14 cells) 18/66 gave me lower temps than the 16/66. Just a heads up.

Just for the record, even on "just" a Warrior the low speed characteristics are very good. Especially on the high-end Lehners, for which the BK controllers were designed, you get a very smooth low speed. I use to crawl over rock piles with my LT revo and a 1950, with adequate gearing.
But your idea is nice, nevertheless. Keep us updated.

Cheers
DAF

[Sneeck]

Don't forget about those little metal pin's that hold the metal pinion's on on the input shaft. They will shear off at some point. Nail solves that problem.

Very cool idea. Like to get a video of this in action.

[crazyjr]

Hey GriffinRU, I just had a thought allong the lines you are working. You could substitute a smaller Novak in place of the 4400 motor and save some weight? Also could eliminate the magnet and save even more weight, may give you more snap as well from the lower rotating mass. Even further along those lines you could eliminate the windings, because you are not using them and take out even more weight if you wanted to, i think.

[Sneeck]

No you need the magnet and windings in order for the sensor to work. Remember that the sensor "read's" in what position the rotor is in and by this can give power to the desired winding in order to work correctly. By eliminating either the spool or winding's I doubt that the controller will power the motor since it need's the sensor to work.

[Serum]

Griffinru; what does the sensor of the novak do? does it deliver a pulse? or does it change in resistance? Nice experiment.

i think it would be doable to make an external sensor.

[Sneeck]

On the back of the motor with some sort of plate. Could be sweet for sure.