I may have some questions regarding sizing components (calculating voltage drops, current requirements, etc) for a circuit. It's been so long that this stuff really is confusing the shit out of me right now.
I'm looking at H-Bridge Motor Control circuits and trying to figure out what components would be required to drive a motor that has a stall current of 20A at 12VDC.
Loosely following this circuit from this website:
He's using IRF630 and IRF9630 MOSFETs. They're rated at (200V, 9A, 75W) and (200V, 6.5A, 74W) respectively. I think the circuit as drawn would basically be limited to a driving a motor that operates at 12V 6.5A max, right? Or is it closer to 6.1A since 12V @ 6.5A = 78W which is over the IRF9630's 74W rating?
So if I want to run a motor that will draw 20A max, then I'd need a P-channel and matching N-channel MOSFET rated at 12V/20A/240W minimum, right?
I'm thinking these would work:
N-Channel 55V/120A/300W: STP150NF55
P-Channel 55V/80A/300W: STP80PF55
Does that make sense? Am I understanding correctly? I'm assuming the other components in the circuit would need to be considered and the resistors matched to the gates on the MOSFETs and the capacitor enlarged to handle the larger motor, but the transistors are my current point of confusion/uncertainty.
The application, in this case, is me simply wanting to understand what goes into a motor controller to drive the motor linked above. I'm going to buy a small/cheap robot chassis in an attempt to play with controlling it using my Raspberry Pi. The motors on it are fairly small and can be controlled with a L293D H-bridge chip ($4). I was looking at other robot chassis that are much larger, and beyond what I'm willing to spend right now to play with, and am just trying to understand what really goes into controlling them.
The Mantis 6WD is a good example as it uses 6 motors that can each draw 20A @ 12VDC when they stall. They sell a dual channel motor controller for about $135, but that machine would take three of them, raising the cost to about $900, just for a chassis with motors and motor controllers.
I doubt I'll do more than play with the little $30 bot I'm planning to buy, but it's interesting and I like to figure out or understand things.
I'm looking at H-Bridge Motor Control circuits and trying to figure out what components would be required to drive a motor that has a stall current of 20A at 12VDC.
Loosely following this circuit from this website:
He's using IRF630 and IRF9630 MOSFETs. They're rated at (200V, 9A, 75W) and (200V, 6.5A, 74W) respectively. I think the circuit as drawn would basically be limited to a driving a motor that operates at 12V 6.5A max, right? Or is it closer to 6.1A since 12V @ 6.5A = 78W which is over the IRF9630's 74W rating?
So if I want to run a motor that will draw 20A max, then I'd need a P-channel and matching N-channel MOSFET rated at 12V/20A/240W minimum, right?
I'm thinking these would work:
N-Channel 55V/120A/300W: STP150NF55
P-Channel 55V/80A/300W: STP80PF55
Does that make sense? Am I understanding correctly? I'm assuming the other components in the circuit would need to be considered and the resistors matched to the gates on the MOSFETs and the capacitor enlarged to handle the larger motor, but the transistors are my current point of confusion/uncertainty.
The application, in this case, is me simply wanting to understand what goes into a motor controller to drive the motor linked above. I'm going to buy a small/cheap robot chassis in an attempt to play with controlling it using my Raspberry Pi. The motors on it are fairly small and can be controlled with a L293D H-bridge chip ($4). I was looking at other robot chassis that are much larger, and beyond what I'm willing to spend right now to play with, and am just trying to understand what really goes into controlling them.
The Mantis 6WD is a good example as it uses 6 motors that can each draw 20A @ 12VDC when they stall. They sell a dual channel motor controller for about $135, but that machine would take three of them, raising the cost to about $900, just for a chassis with motors and motor controllers.
I doubt I'll do more than play with the little $30 bot I'm planning to buy, but it's interesting and I like to figure out or understand things.