FE motor question

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Wasted wages

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Jan 2, 2006
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Can anyone give a quick explanation on why the newer brushless motors have three wires going into them ?

Is it wound like an alternator on a car is?
In a 3 phase delta configuration?

Any technical links to how the speed controllers convert the DC battery voltage to the input voltage for the motor windings would be appreciated!
 

RaceMechaniX

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Apr 27, 2007
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2,605
Brushless motors are three phase AC motors. In the simplest configuration you have three stator phases and 2-pole rotors. Stators can be wound as Delta or Wye. Most car motors are sensored and have a hall effect array to measure rotor angle. This is used for smooth starting at low RPM. For boats it makes no difference and 99% of motors and controllers can be run in "sensorless" mode. For boats, most of the motors are "inrunner" style where the rotor is on the inside of the stator. Rotor poles are typically 2/4/6. The more poles typically the more torque per amp of output from the motor.

Wikipedia BLDC
 

Wasted wages

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Jan 2, 2006
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548
Another question....

Are these FE motors that are used on outboards waterproof ?? or water resistant ??

What's the procedure after a flip and sitting upside down till the retrieve boat picks it up ?
are the bearings and windings sealed ?
 

RaceMechaniX

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Apr 27, 2007
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2,605
You should treat an outboard FE motor just like a nitro motor. If it gets dunked you should blow out the water and use something like Corrosion X to displace the water and prevent corrosion of the shaft and stator laminations. After the day, ideally you take the motor off the lower and add oil to both bearings.
 

Wasted wages

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Jan 2, 2006
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When you say blow out the water, aren't the motors completely closed up and sealed ?
Sorry for all the stupid questions, but I have never seen a FE boat up close and in person...
 

donaldhuff

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Feb 13, 2017
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I agree with the "blow it out" part, but I have taken apart a couple of hundred motors by now. And some of them have come into my shop dripping with corrosion X, easy to tell because they STINK!

That oily stinky stuff does attack some of the rubber heat shrink that some motors use for insulation. I have rewound a few motors that burned up because the oils turned the insulation to mush. And that allowed the leads to short between each other.

If you do use corrosion X or wd40, I suggest blowing as much of it out as you can.

I just blow mine out with air and run it again to get it warm. I do understand that outboards are a different matter though and may need special attention.

To answer your question Wasted wages, NO neither the windings nor the bearings are sealed. If you can run it after dunking it and blowing out, that will get it warm enough to dry most of the water out.
 

donaldhuff

Member
Joined
Feb 13, 2017
Messages
5
Tyler, off subject a bit but, are they really AC current? Or is the esc just pulsing the DC and controlling the "ON time" of the pulse, and then switching the polarity of the next pulse. which in a way is like changing the hertz.
 

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