Very interesting Setup from Mega Motors

[sleebus.jones]

Squee, you've got it spot on. Motors are designed to do a specific amount of work. It's just like a horse, no matter how hard you whip it, once it's going as hard as it can, it's not going to work any harder. If you need more work done, you either need:

1. A different horse

or

2. More horses!

Yes, if the KV changes, you've changed "horses" and the draw will be different for the same work done. It's not as over your head as you think! :)

Artur: When you apply more volts, you get more RPM, up to the limit of the work the motor is able to do. It's the same analogy with the horse, you'll only get so much out of the motor, regardless of what you do.

Sleeb

[GriffinRU]

Originally Posted by sleebus.jones

Squee, you've got it spot on. Motors are designed to do a specific amount of work. It's just like a horse, no matter how hard you whip it, once it's going as hard as it can, it's not going to work any harder. If you need more work done, you either need:

1. A different horse

or

2. More horses!

Yes, if the KV changes, you've changed "horses" and the draw will be different for the same work done. It's not as over your head as you think! :)

Artur: When you apply more volts, you get more RPM, up to the limit of the work the motor is able to do. It's the same analogy with the horse, you'll only get so much out of the motor, regardless of what you do.

Sleeb

I will make it simple...

If you get light bulb rated at 12V and apply 16V you won't get more light but it will draw more amps and won't last long. Why? Because of fixed resistance. But how much light it will produce will be based on how big is the light bulb. Now apply the same to the motor...

Artur

[sleebus.jones]

Originally Posted by GriffinRU

I will make it simple...

If you get light bulb rated at 12V and apply 16V you won't get more light but it will draw more amps and won't last long. Why? Because of fixed resistance. But how much light it will produce will be based on how big is the light bulb. Now apply the same to the motor...

Artur

First problem is that you are wandering off into another area. I'm not talking about ohm's law (resistance) at all. Also, if you overvoltage a light, you will get more light out of it. If you shove more energy into a circuit, you are going to generate more heat. Heat is what makes light in an incandescent bulb. Make more heat, you make more light.

Take a look at this link here:

http://science.howstuffworks.com/question501.htm

Maybe that'll do a better job of explaining it than I have.

Sleeb

[GriffinRU]

Wow, even light bulb was hard...

BrianG and you are about back EMF...

Artur

[BrianG]

I just read the that HSW article and I didn't particularly like their lightbulb example. The way it was stated led the reader to believe a 100W lightbulb will always produce 100W no matter the applied voltage.

The incandescent lightbulb is also a bad example because the filament does not have a linear resistance either. Its resistance is close to 0 when no current is flowing (off) and the resistance increases as it heats up from the current flow. Incidentally, this is why a bulb amost always blows when you first turn it on - from the initial inrush of current while the filament resistance is lowest.

[GriffinRU]

Originally Posted by BrianG

I just read the that HSW article and I didn't particularly like their lightbulb example. The way it was stated led the reader to believe a 100W lightbulb will always produce 100W no matter the applied voltage.

The incandescent lightbulb is also a bad example because the filament does not have a linear resistance either. Its resistance is close to 0 when no current is flowing (off) and the resistance increases as it heats up from the current flow. Incidentally, this is why a bulb amost always blows when you first turn it on - from the initial inrush of current while the filament resistance is lowest.

100W of equivalent optical power, which will be based on temp of filament, which has its max at say 5000K then it melts...

Artur

P.S. howstuffworks -> internet is fantastic :)

[BrianG]

Originally Posted by GriffinRU

100W of equivalent optical power, which will be based on temp of filament, which has its max at say 5000K then it melts...

Artur

P.S. howstuffworks -> internet is fantastic :)

Yeahg, but they weren't really clear, that's the problem. People who don't know can be led to make some assumptions that aren't correct. Besides, light output isn't usually measured in watts...

For the most part, HSW really is good "stuff".