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Old 06-15-2014, 10:31 PM   #1
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Default Can someone pls clue me in on what a "phase" is

Sorry, I know that this is kind of a stupid question. I know this because that is the very reason that I have never asked about it in the past. I want someone to help explain what a "phase" is when referring to an ESC's amperage capabilities.
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Old 06-15-2014, 11:53 PM   #2
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Brushless motors used in RC are typically 3 phase.

The ESC in effect is a DC to 3phase converter. Your battery being DC.

So its the current the ESC can put out into each phase - a good ESC will be equal of course!

Background reading, semi relevant

http://en.wikipedia.org/wiki/Brushle...electric_motor
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Old 06-16-2014, 03:42 AM   #3
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Yep, what he said.

By analogy with triple phase power generation (at home you have single phase) which was adopted for reasons to do with efficiency.

Basically you have three motors in one (if you want to compare with DC motors), or better put three simultaneously working motors rather than three alternately motors as in a DC motor where the commutation to the right field is done mechanically by the commutator (sic!) hence three magnetic fields offset at 120 degrees, so you have to keep everything where it needs to be (in terms of how you connect the motor to the ESC) or you'll apply the corresponding field to the wrong winding (out of synch) with the expected outcomes.
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Old 06-16-2014, 01:59 PM   #4
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AC motors use rotating magnetic fields to spin the rotor. DC motors use brushes and the commutator to create the rotating magnetic field. In ac the rotating magnetic field speed is a function of the hz of the source. By varying the number of poles you change the speed of the motor. The formula for AC motor speed is: speed=120*freq/#poles. For the hobby motor/controller sets freq becomes the variable. Voltage plays into the strength of the magnetic field but is not a factor in the speed of a motor. With land based ac motor installation the formula is always 7200/#poles because a synchronous motor runs on 60hz unless it is some kind of specialized equipment with a VFD.

These modern rc motor/speed control sets are in effect miniature 3 phase inverters with a variable frequency drive to control motor speed. Modern electronics efficiency and price point has made this technology feasable.
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Old 06-22-2014, 12:19 AM   #5
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right on thanks guys
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