I got this BLDC motor with integrated controller. The controller requires a 3.3V PWM wave and should run at its maximum speed of 15,000 RPM with 100% duty cycle. So I am currently plugging the 3.3V wire from the arduino straight into the controller which only gives me 10,000 RPM. The manufacturer said its due to voltage drop across the wire. However, the wire from the arduino to the motor must be 8 inches at most.
Surely the voltage dropped across this length of wire is not even noticeable?
And, do you have a link to the motor specs? And a link to your power supply specs?
If it's a voltage drop "across wires" it would be a voltage loss across the power & ground wires, not the PWM voltage.
It's also possible that the PWM voltage (or 3.3V) out of your Arduino is low for some reason. Have you measured the 3.3v?
If you have a multimeter (DMM) you can measure the voltage at the power supply and at the motor. If the problem is low voltage the power supply is probably too "weak". That is, either the voltage is too low, or it can't supply the required current and the voltage is dropping when the motor runs.
If it's a high-power motor (lots of current) it's possible to get significant voltage loss across the wires & connections/connectors. With short wires (to the power supply) you'll usually get more voltage drop across the connections than across the wires.
If you are getting voltage drop across the wires & connections you can get voltage drop across both the power AND ground connections. So it's best to measure the voltage at the motor, with the ground lead of your meter also at the motor.
Please read the first post in any forum entitled how to use this forum. http://forum.arduino.cc/index.php/topic,148850.0.html .
Then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
So I am currently plugging the 3.3V wire from the arduino straight into the controller
The 3V3 output from a Uno is limited in what current it can supply. It is probable that the controller is drawing too much current and as a result the voltage is dropping. Measure this 3V3 line when it is connected to the controller.
Also is the ground of the controller connected to the ground of the Arduino?
couldnt attach image
You need the URL of the image NOT the URL of a webpage that contains the image.
