Castle - Make A Special Edition Monster

[BrianG]

Originally Posted by GriffinRU

It would overheat in no time.

Really? Hmm, I would've thought otherwise. Make the motor large enough and do some electronic trickery to reduce the current X number of seconds after each step coil is energized, or something like that.

[Pdelcast]

Originally Posted by GriffinRU

Patrick, as I said earlier for given application.

If optics are slow than you are really fast my friend!!!!!!

Quote:
Originally Posted by GriffinRU
20% PWM at stall is not high current if you matched with magnet pole and motor is rated for the load.

Incorrect -- think about it. (Hint -- it has to do with back-emf)

No comments, Maybe I am not clear, but how you get the motor moving if you cannot draw the current...

P.S. It is pointless discussion, you like what you have, I am trying to let you know how it can be done right for given application.
You current sensoreless ESC is great for RC but I am looking for rock-crawlers as application for brushless as well.
And out-runners are great motors and with sensors can be direct coupled to wheels...

Sorry griffinru -- my post was put up while I was still editing it. So you didn't see the final version.

The stall current thing is a 1/X relationship current vrs RPM -- non linear with RPM. So at stall, current is infinite (limited by motor phase resistance -- not much of a limitation.)

[GriffinRU]

Originally Posted by BrianG

Really? Hmm, I would've thought otherwise. Make the motor large enough and do some electronic trickery to reduce the current X number of seconds after each step coil is energized, or something like that.

Stepping through the rocks would be hard, while smooth rolling would be great. Stepper's are good when you need holding torque, but they are not efficient as you can see. While at mid-to-high RPM you can stall them at unexpected load.

[Pdelcast]

Originally Posted by BrianG

Really? Hmm, I would've thought otherwise. Make the motor large enough and do some electronic trickery to reduce the current X number of seconds after each step coil is energized, or something like that.

Brian,

Think about a brushless motor as a stepper motor with magnets and a synchronous controller. :)

[BrianG]

Yeah, I understand that, but I figured since there are so many more phases to get more samples from, slow running would be smoother. In effect, a hundred-phase BL motor.

In a regular 3-phase BL motor, you have to get so many revs before you can get a good reading on actual rotation, so slow/stall conditions are harder to deal with.

Just throwing ideas out, sometimes it's nice to think outside the norm...

[GriffinRU]

Originally Posted by Pdelcast

Sorry griffinru -- my post was put up while I was still editing it. So you didn't see the final version.

The stall current thing is a 1/X relationship current vrs RPM -- non linear with RPM. So at stall, current is infinite (limited by motor phase resistance -- not much of a limitation.)

Post #666...
It doesn't matter, you do not like sensors, it is alright.
You have interesting opinion about optics.

[johnrobholmes]

I have done some research on stepper type motors for crawling, and the main issue is the resistance of the phases (in effort to prevent ridiculous amp draw) and that the ESC would have to be matched to the motor in terms of PWM so that the coils didn't blow under load.

It would be much simpler to just throw a sensor on an outrunner to bump up the starting torque and zero rpm sync, then switch to sensorless at around 500 to 1000 rpm depending on motor. Some over current protection might be a good idea.

[GriffinRU]

Originally Posted by BrianG

Yeah, I understand that, but I figured since there are so many more phases to get more samples from, slow running would be smoother. In effect, a hundred-phase BL motor.

In a regular 3-phase BL motor, you have to get so many revs before you can get a good reading on actual rotation, so slow/stall conditions are harder to deal with.

Just throwing ideas out, sometimes it's nice to think outside the norm...

There are 2 phases (sometimes 4, still wired as 2) and just 200/400 slots rotor, think sync as Patrick said. The only feedback is encoder...

[bdebde]

Originally Posted by GriffinRU

...MGM hardware with CC software - I am hearing that allot. Patrick have you checked what is different between your creation and theirs?

I would guess by the layout of the MGM, they have more (or larger package) fets. If my third try on the MMM fails, I would be willing to Frankenstein together my MGM power boards with the MMM brains for a totally bulletproof ESC (sorry Patrick).

GriffinRU: can it be done? (brain transplant)

[GriffinRU]

Originally Posted by bdebde

GriffinRU: can it be done? (brain transplant)

Not really,
The trick is at fet's drivers not in fets. While they do have nice layout, CC's board is also nice. But there is a small difference which is clear on the board and inside firmware as well. I think if Patrick will do the same, he might get similar performance with current firmware.
But, Frankenstein, in this case would be very complicated.

New MGM's I think have the same fet as CC, if you check old 160Amps ESC had 4 boards now 160Amps has 3 while 224Amps has 4...

[bdebde]

I guess I will have to install the MGM in my truck this weekend (just got it back with 3.23 firmware), since it looks like I will have to wait a while on the MMM sent in for replacement. Maybe the new firmware on the MGM will allow me to run reverse without all the quirks (crosses fingers). Castle IS by far better on the software side, I run reverse on the mm's (as well as the MMM for the whole 5 min I got to run it) and never worry about it, until I need it, it just all works like it should. I have had all kinds of wierd things go on with the MGM at one time or another. One nice thing on the MGM is the ability to read out the max temp (internal) and the amps (hint, hint Patrick).

[lutach]

Originally Posted by bdebde

I guess I will have to install the MGM in my truck this weekend (just got it back with 3.23 firmware), since it looks like I will have to wait a while on the MMM sent in for replacement. Maybe the new firmware on the MGM will allow me to run reverse without all the quirks (crosses fingers). Castle IS by far better on the software side, I run reverse on the mm's (as well as the MMM for the whole 5 min I got to run it) and never worry about it, until I need it, it just all works like it should. I have had all kinds of wierd things go on with the MGM at one time or another. One nice thing on the MGM is the ability to read out the max temp (internal) and the amps (hint, hint Patrick).

Let me know how your MGM does with the Neu.

[bdebde]

Originally Posted by lutach

Let me know how your MGM does with the Neu.

Sure thing.

[TexasSP]

I have the new software and run it with the medusa with none of the reverse quirks that it had running the 600xl. The medusa's being four pole should be quite similar to the neu in behavior I would think.

[marzac2]

I've had great success with my MGM controller and the updated firmware. I run a Neu 1512.