DUAL Purpose Castle Creations ESC?

[heli_ebook]

Anybody KNOW about WHERE on the PCB of a Castle Creations ESC you would tap for vanilla D.C. output to use the thing as a BRUSHED ESC? :cool:


It's in there somewhere, anybody know where though?

[Norman Adlam]

Hi,

That was one of my thoughts a year or two ago. :D
It ought to be easy for the manufacturers to add into the programming an option to use a brushless ESC as a brushed ESC - just ignore the feedback, and either signal all phases to be the same, or just one!

Dunno why no-one has done it, maybe it's harder than I think. :(

Sorry, can't help you with your question though...

Cheers,

[slipstick]

Schulze (and perhaps Kontroniks) did do it years ago even though it isn't quite that simple ;). The either/or ESCs cost quite a lot more than most brushed ESCs and soon disappeared.

As for CC....it's possible there is a simple PWM low level signal in there somewhere but it would almost certainly take a lot of work to drive any of the ouput MOSFETs from that rather than from the intended complex switched phase signals.

Steve

[Unterhausen]

It's in there somewhere, anybody know where though? It isn't in there in the current form. A microcontroller drives the output bridge in an alternating pattern in order to commutate the brushless motor. A brushed motor esc could be made with exactly the same hardware minus 2 output transistors. You can't use the brushless controller without a software change. You would only use 2 of the 3 motor wires. I have seen this on AMC servomotor brushless amps. I never really understand why they bothered.

[gkamysz]

Castle the feature available on some of the car controllers.

[Miami Mike]

I wonder if this would work:

http://static.rcgroups.com/forums/attachments/1/5/7/8/9/a1745489-162-brushless-brushed.gif

Would the processor in the ESC sense something wrong and not operate?

[TheSteve]

Castle the feature available on some of the car controllers.

Its actually supported by all of there car controllers with the newest firmware.

They could add it to any of the brushless ESC's if they wanted to.

[heli_ebook]

Yeah... that's kinda what I figured!

[Norman Adlam]

I wonder if this would work:

http://static.rcgroups.com/forums/attachments/1/5/7/8/9/a1745489-162-brushless-brushed.gif

Would the processor in the ESC sense something wrong and not operate?
Hmmm... I think the problem would still lie in the software, Mike.
It will still be trying to measure the small feedback voltage in order to determine what phases to fire. Currently, if it can't get sensible info, it gives up.

Cheers,

[Miami Mike]

Right, that's pretty much what I figured. I think it's a valid solution electronically and wouldn't require digging into the circuitry, but like I pointed out above, the ESC wouldn't sense what it expected.

Anyway, brush-type ESCs are so cheap these days that it couldn't possibly be worth the trouble. I was just treating it as a sort of puzzle.

[Norman Adlam]

Right, that's pretty much what I figured. I think it's a valid solution electronically and wouldn't require digging into the circuitry, but like I pointed out above, the ESC wouldn't sense what it expected.

Anyway, brush-type ESCs are so cheap these days that it couldn't possibly be worth the trouble. I was just treating it as a sort of puzzle.
Yeah, but the software solution would be very simple, I think! Just an option to stop expecting any phase feedback, and set each phase to fire for a fixed 33% of the time!

The advantage (to me) would be that I wouldn't have to have separate brushed controllers - I could move my existing brushless ESCs around (giving me all the newer 'goodies', like variable cell cutoff voltage etc). Also the load would be shared between each phase, so a relatively small brushless ESC would be able to handle a higher current than a similar brushed ESC.

The software could be retro-fitted to existing ESC - with us just adding the steering diodes!

Currently, brushed controllers are still almost the same price as brushless controllers.

(All above are just my guesses! :rolleyes: )

Cheers,