12020 questions - RC-Monster Forums

BrianG · **12020 questions -** 03.18.2006, 01:15 AM

I got my 12020 ESC the other day and was wondering something. It came with a single set of power wires (red and black), but has dual sets of motor wires for each of the three phases. After thinking about it, why would it be set up this way? Both the power and motor wires use the same guage wire. You'd think if anything, they'd double up on the power wires and use single motor wires since each motor wire will be pulling a fraction of the power at any one time, while the power wire will be pulling the full current. Or use larger guage wire on the power side...

Something else; not that I will be doing this, but can each set of motor wires be used to power a separate BL motor (two total)? Of course, I'd have to make sure the motors wouldn't pull more current than the ESC could handle, but is it possible? For best effect, both motors should probably be the same ratings. The ESC circuitry would measure the current pulses of both motors added together.

Anyway, just curious.

coolhandcountry · 03.18.2006, 08:32 AM

It is possible to run two brushless motors on one esc. You have to make sure the motor are timed with one another though. Has to be the same motora as well. I am not sure how you go about putting them in time though.

Sylvester · 03.18.2006, 03:02 PM

I dont think bl motors have timing right?

maxxdude1234 · 03.18.2006, 03:15 PM

They do have timing, but its the controller that sets the timing. I think coolhand was talking about the rotors in each motor being in the same position. And in answer to his question - I don't know. Maybe someone else does.

Quote:

You'd think if anything, they'd double up on the power wires and use single motor wires since each motor wire will be pulling a fraction of the power at any one time, while the power wire will be pulling the full current. Or use larger guage wire on the power side...

That is incorrect, whatever goes into the controller has to come out - whether it be to the motor or in heat. Therefore the current along the power wires will be the same as the current along the motor wires.

BrianG · 03.18.2006, 05:35 PM

I guess timing makes sense, you would have to make sure the magnet (rotor) is in the same starting position in relation to the coils on both motors or the ESC would send power at the wrong time on one motor and both motors would end up fighting each other somewhat.

maxxdude1234: I understand what you are saying, however in normal three phase AC motors, the power on each coil is 60 degrees out of phase with each other coil. I would imagine the same theory applies to BL ESCs/motors. Your explanation would definitely make sense with normal "single phase" brushed motors though. So, following my thought, it makes sense that each individual motor wire would see less current flow than each power wire at any one time. I don't mean to argue, I'm just trying to understand this. I'm sure the ESC will perform well, especially since I don't plan to ever draw 120A (not that my batteries will allow it).

coolhandcountry · 03.18.2006, 05:43 PM

How would you go about getting the motors in sink with each other. You would have to hook each one up the same as well. Could you put a small amount of current to each one to get it centered.

BrianG · 03.18.2006, 06:01 PM

Maybe take the rear plate off and make sure the magnets are in the same relative position?

coolhandcountry · 03.18.2006, 06:37 PM

But the magnets look the same all the way around. so it is not visual way to look at the magnet. I was thinking like a 1 volt power on a phase of it. Then the magnet should center itself on that phase. You would have to do the same phase as you would hook the wires up.