Where can I find a write up with pictures that show how the electronics work in an Electric Powered PLane.

Specifically I am looking to find out WHAT does an ESC do? Obviously it controls the Speed of the Motor but how? How is it connected? Directly to the motor? To the RX? I would love to read up on this stuff but when I did a search for "ESC" it turned up a bunch of people asking WHICH ESC to get with their motor etc...

Sorry for the n00b ? but I am interested...

Microchip.com has some application notes that will get you started. Look for AN857, AN885 and AN899, there are others for brush type motors.

Below is a hookup diagram for the electronics in a typical electric plane.

The ESC (electronic speed controller) connects to the battery, the motor, and the receiver. The ESC serves three main functions.

Controls motor speed
The details of this function differ depending on whether the motor is a brushed or a brushless motor. But in any case, the ESC takes the battery voltage and applies it to the motor in a manner that varies when you move the throttle control on your transmitter.

Battery Eliminator Circuit (BEC)
In electric planes, keeping the weight low is often very important. Since a battery is usually the heaviest component in a plane, it is helpful if you can use just one battery to provide power for both the motor and for the receiver and servos. So most ESCs contain a Battery Eliminator Circuit (BEC). The BEC regulates the battery voltage down to a lower voltage that is appropriate for the receiver and servos. This eliminates the need for a separate, second battery for the receiver and servos. Hence, the term Battery Eliminator Circuit. The ESC connects to the throttle channel on the receiver and sends power to the receiver through that connection.

In larger electric planes where low weight is less important, it is common practice NOT to use the BEC and to instead use a separate battery for the receiver and servos. Obviously, a separate battery for the receiver and servos provides a degree of reliability, so even if the motor battery fails, you still have power for the control surfaces.

Low Voltage Cutoff (LVC)
Some types of batteries, notably lithium polymer (lipo), can be damaged if discharged below a certain voltage. Most ESCs now include a Low Voltage Cutoff function. As you are flying, if the battery voltage drops below a pre-set level, the LVC reduces or cuts off power to the motor only, while the ESC continues to provide power to the receiver and servos. This gives you a chance to land the plane before the battery is damaged and while there is still enough power to operate the receiver and servos.

- Jeff

one other thing that I might add is that esc's use PWM (pulse width modulation). Basically you have a mosfet, and basically that is an on and off switch that is capable of switching anywhere from 2000 times per second on up. How it works is if you want 70% throtte, it leaves the switch on 70% of the time, and off 30% of the time. So in this way you are getting 100% of the power 70% of the time, which looks like 70% power.

Go to http://www.ezonemag.com/ and then click on FAQs.

Wow - you guys really know your stuff! This is great info. I really appreciate the explanations. That diagram was exactly what I was looking for so thank you very much. I have been reading those FAQ's and will continue to do so before I post anymore questions. Also - Thanks for the explanation on PWM. That makes complete sense how you explained it.

Dave - Those documents are a little over my head. (Actually WAY) over my head lol. I had a look through them tho and it made me want to dig out my circuit analysys books! haha

Well - gotta run! Thanks for the info yall!

Jerry