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Topic: +, -, GND (Read 2 times) previous topic - next topic


the document is WAY too long and complicated!
In a nutshell please...

It is a motor. It requires no sensors and has no brushes.

One wire is for each of the phases. You need to supply a three phase signal to make it turn. That is three sin waves 120 degrees apart. The frequency of the sin waves will determine the speed of the motor.


Ground is basically connected to the main switch in house as we do not give ground to every device (some may not need ground so ground do act as negative in devices) so the two wires attached to motor are two,one + and other - which is also ground.


Sorry but that doesn't make any sense and does not address the problem in this post.


I think you are referring to how the physical earth ground in a regular electrical service is connected at the main panel with the neutral, and how essentially grounding the motor casing gives it the same potential as the neutral(hopefully assuming the ground is electriclly clean) and would provide protection from shock in the case of instead of electrifying the outer case due to a failure, the breaker would trip disconnecting power to the circuit
however in this case it seems this motor isn't going to be connected to the mains, and so it wouldn't protect it from say the 12v supply shorting to the case, not that that would hurt anyone anyway
All your questions could be answered if you were to find the datasheet


There are obviously two different subjects being interleaved in this thread. First is about the definition and usage of the word 'ground' as it applies to electronics. While the OP used it his original posting, it's pretty clear he really wanted to know what/how to wire up a 3 phase brushless DC motor, which has no use for nor applicable to 'ground'. So while most post responces here talking about ground are not incorrect, they are not what the OP really meant to ask for, nor requires to understand what he needs to get his motor to run.

The motor in questions has more in common with a 3 phase AC motor then a true DC motor. It requires a motor driver/controller to generate the proper 3 phase signal at the proper frequency, voltage, and current capacity required for the motor. In reality one never just purchases such a motor without also purchasing a driver/controller module compatible to the actual motor selected. These are usually called ESC, for electronic speed controller. Then one controls the ESC by sending in standard +5vdc servo ppm control pulses. There is usually a start-up 'arming' sequence one has to send to the ESC before the motor will actually obey the servo control pulses, for motor start-up safety. Most ESCs also output a regulated +5vdc power source pin suitable for powering things requiring up to around 2-3 amps for +5vdc loads, this is usually called a BEC feature, for battery eliminator circuit. The main power source for a ESC is usually battery power specified for a certain voltage range and rated to be able to supply the peak current demand for the ESC and motor. Again the main battery, brushless motor, and ESC must be selected as a set to insure they are all of a compatible voltage and current range suitable for the motor.


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