Hey LMR I was hoping you could help me with a few questions the internet/google cannot fully teach me haha.
So I am thinking about maybe making a combat robot/battle bot (http://www.robotmarketplace.com/therobots.html) whatever you want to call it with some left over cash. So I have some questions on Brushless and Brushed motors.
What is the difference between Brushed and Brushless? So far I understand that one has three wires and the other two- +, - , brushless has a servo wire( to make it simple for me ;) So what am I missing? Is one geared or what?
Also I think I understand that I have to have a ESC with BEC for another battery for the motor. Am I correct? And would I need two? One per motor?
Sorry for the multiple questions but please help a guy who needs some good teachers to explain it to him :) thanks
Feel free to ask me anything- Such as my intent/ what I know/ anything. Thanks
Many robots you will see use simple brushed DC motors. These use two wire control, and can be driven simply by putting a voltage difference across the two leads. Reverse the voltage and you reverse the direction the motor spins. To get enough practical torque for most applications, you will find you need gears on your motor to slow it down and make it more powerful.
Brushless DC motors require a more complex Electronic Speed Control (ESC) to run. They tend to be more expensive, but are more powerful and efficient than a brushed DC motor.
A servo is just a motor that has position feedback control. Hobby servos like we find in use for RC vehicles and robotics use a brushed DC motor with the drive electronics, gearing, and a potentiometer for the position feedback all in one package.
A Battery Elimination Circuit (BEC) is used in RC vehicles to provide power to the electonics from the main drive battery for the motors. If the battery level drops below a set threshold, the BEC cuts power to the motors, but maintains power to the controls so you can guide your vehicle (especially airborne RCs) home. Many ESC units include a BEC, but BECs are also sometime separate units. You need to size your ESC and BEC carefully to your batteries and the intended load of your motors and electronics.
For instance, this robot (one from your link) weighs 108 pounds http://www.robotmarketplace.com/locust1construction.html . If you want something even near that size then those motors are way too small. Those motors have about 4.4 pounds of torque at 6 volts.
Ya no I dont plan on going that big I just want to make one for fun. Not really planning on competions just wanting to get involved and learn stuff. I plan on 5lbs or less
In this corner weighing in at 90 bounds… WALTER!! Designed by Chris the Carpentner, with a niffty Transmittor. In the other corner, weighing in at a unknown weight for the time. Makeitcool’s BATTLE BOT, which we have little clue about, but would like to know more about.
Ok I know I can get better motors and so on but lets go back to what I said earlier. Will my motor and BEC work for what I want? thanks for all your help patrick
A BEC is just a voltage regulator. RC people use them to supply 5v to their RC receiver and servos. What kind of motor controller are you going to be using. A brushed ESC or some other controller? What battery will you be using?
As Patrick said, those motors would be for a smaller robot.
Regarding the BEC, you don’t necessarily need one, but you do need some sort of power for your motors and electronics. The BEC you linked provides 5A @ 5V. Your two motors have a stall current (maximum load) of 1.6A each. So the BEC would certainly work, but might be overkill.
Check out OddBot’s post on voltage regulators, which may be a lot less expensive. You need to determine what the overall load of your robot (power for motors, servos, electronics, etc.), so you can design or buy the appropriate power source.
oh ok so I might not need a BEC? I have a 6 or 7.2 battery at the moment for the reciever power and like 3 servos on one project but I wouldnt use them here. Ill try to get everything I would have on there asap
