Generator circuit diagram question

[Jykos]

I'm building a water turbine. There are more coils however for my question I have simplified to two:

What happens to the voltage across the resistor if the top coil (coil 1) has a higher potential than the bottom coil (coil 2)? 

 

[Mark77]

They're tied together in parallel, so the potential (voltage) must be identical. 

[Jykos]

1 minute ago, Mark77 said:

They're tied together in parallel, so the potential (voltage) must be identical. 

I know, but what happens if one say, has more turns, How will voltage balance?.

I'm starting to think I'll want them in series as kirchovs law (that piece of s#@t) means that the "lower voltage" one would act kinda as a resistor? Maybe? I'm no expert.

[Jykos]

i.e. if coil 1 can produce 4V 1A by it's self and coil 2 can produce 2V 1A: Will they add to 2V 2A or 4V 1.5A or something else?   

[Mark77]

Yes the one with more turns will produce more current. 

 

In rotating DC machinery, there is the concept of "back EMF".  A concept you may need to refer to explain just how it will work in an actual machine.

 

 

 

 

[Jykos]

2 minutes ago, Mark77 said:

Yes the one with more turns will produce more current. 

 

In rotating DC machinery, there is the concept of "back EMF".  A concept you may need to refer to explain just how it will work in an actual machine.

 

 

 

 

Will the power output (of the resistor) be less than that of a generator with the coils in series?

[Enderman]

2 minutes ago, Jykos said:

i.e. if coil 1 can produce 4V 1A by it's self and coil 2 can produce 2V 1A: Will they add to 2V 2A or 4V 1.5A or something else?   

It would be 3v, and the current 2A, although the two generators should ideally be producing the same voltage or one can get damaged from backflow.

[Jykos]

Just now, Enderman said:

It would be 3v, and the current 2A, although the two generators should ideally be producing the same voltage or one can get damaged from backflow.

Ok, thanks.

They are literally just coils of wire so backflow isn't an issue. Optimizing power output is however.

[Jykos]

3 minutes ago, Enderman said:

It would be 3v, and the current 2A, although the two generators should ideally be producing the same voltage or one can get damaged from backflow.

If that's true then the power output should work:

3*2=1*(4+2)

[Mark77]

Quote

Will the power output (of the resistor) be less than that of a generator with the coils in series?

Well a series wound motor will deliver higher voltages.  But eventually those voltages become excessive. 

 

Large DC train locomotives, for instance, will start out with their motor windings configured in "series", but will eventually transition to parallel operation to keep the voltages from exceeding limits. 

[Jykos]

4 minutes ago, Mark77 said:

Well a series wound motor will deliver higher voltages.  But eventually those voltages become excessive. 

 

Large DC train locomotives, for instance, will start out with their motor windings configured in "series", but will eventually transition to parallel operation to keep the voltages from exceeding limits. 

HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAH

(my voltages are sub 2V on a good day. Its a small turbine for hiking)

[Jykos]

And I should note its an AC generator (diagram was for simplicity)

[Mark77]

What kind of AC generator?  Synchronous?  You have issues of excitation in that case, and reactive power flows in the windings.  Plus you have to use phasor math to analyze it. 

 

 

[Jykos]

1 minute ago, Mark77 said:

What kind of AC generator?  Synchronous?  You have issues of excitation in that case, and reactive power flows in the windings.  Plus you have to use phasor math to analyze it. 

 

 

I have some googling to do...

I can say that all coils are in the same state (current flow) at all times.

[Unimportant]

4 hours ago, Jykos said:

i.e. if coil 1 can produce 4V 1A by it's self and coil 2 can produce 2V 1A: Will they add to 2V 2A or 4V 1.5A or something else?   

It will be a 2V short circuit and waste of energy. You can balance them by putting a small (power) resistor in series with each coil. That'll also waste energy but less then a pure short circuit.

[Unimportant]

5 hours ago, Jykos said:

I know, but what happens if one say, has more turns, How will voltage balance?.

I'm starting to think I'll want them in series as kirchovs law (that piece of s#@t) means that the "lower voltage" one would act kinda as a resistor? Maybe? I'm no expert.

Yes, in series the current will be limited by the coil with the highest internal resistance.

Afaik, the only way to efficiently balance them (thus, without wasting too much power in some way) is with active electronics.

[TheCi]

It would be better then to simply assume a real world coil (or transfos for that fact) as a single component to always look at them as 2 things in a diagram: an inductor and a resistor in series. That way you can avoid the confusion that comes from having your parallel diagram and it makes the circuit analysis a bit more clear.