This isn't really an arduino specific question but there is some incredibly knowledgeable people on here and ultimately I want to use an arduino to control my project so I thought I'd ask you guys
I need to control a 24v BLDC motor, which seems simple enough I guess using an ESC. I'm not too bothered about speed however I do need to drive it in both directions and almost all of the cost effective ESC's I've researched seem to be unidirectional.
So my initial question is, do these motors work in a similar way to a conventional 3 phase motor, ie, if I swap 2 phases will it rotate in the opposite direction? If it does then I can just use a couple of relays to swap 2 of the 'phases'. Messy I know but it would work.
If not, any recommendations for a bidirectional ESC ?
Motors are not created equal, with information on the motor I cannot give you a definitive answer. For example in a three phase BLDC you need to reverse two of the Hall sensor wires and the correct pair of the Phase wires. Note only one of the three phase wire swap options will work correctly. Different motors different methods. Some do not have sensors.
I take the easier approach: they are 3 phase stepper motors. If you want to build your own ESC then simply reverse the order of phase excitation in code instead of swapping phases by relays.
As already mentioned: if the motor includes Hall sensors then you have to care for many parameters, like possibly asymmetric phase shift with reverse rotation.
Unfortunately this is a 'reverse engineering' project and I have zero information on the motor apart from it having 24v stamped on it !
It has 8 wires so I'm assuming (yes, I know that's dangerous and almost always wrong !) that 3 are the A,B,C 'phases' and the other 5 are hall plus, hall minus, hall A, Hall B and Hall C ... although I have no way yet to determine which is which.
Using a meter I've found 3 wires that all measure 10.5 Ohms between them. If I touch any 2 of those together the motor becomes harder to turn (like when checking for pairs on a stepper motor) and if I touch all 3 together the motor becomes even harder to turn, so I'm pretty sure those are the 'phase' wires. As I only need to drive it in both directions I was hoping that I could use a simple 3 wire ESC and not bother with the hall wires. Not a prefect solution I know but good enough for my needs.
Now I understand a bit more I'm thinking of two (well, one and a half actually) L298's in half bridge mode. Then I should be able to manipulate the direction in software.
Still not sure if I'll need to interrogate the halls. For my particular application I think I can ignore them once the motor is rotating, but maybe I'll need them to understand where the motor is to get it started in the first place.
