# DC generator question -- what is happening at no load? (1 Viewer)

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#### dave pallamino

In the case of a d.c. generator, if V=E–IaRa when current flows through the armature, why does V = E at no load?
Why does the resistance element become disregarded at no load? Is this because the resistance can't cause the voltage to drop at no load?

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#### scottdave

Homework Helper
Gold Member
How is the armature current related to the load current? What can you say about the armature current under no load condition?

If you are having a hard time visualizing "no load". Then imagine a resistance load and you start increasing the resistance. When you get to the order of a Megohm (like what a voltmeter may have), how much current is through the armature, and what is the votage approaching?

#### anorlunda

Mentor
In the case of a d.c. generator, if V=E–IaRa when current flows through the armature, why does V = E at no load?
Your question makes no sense. In that equation, what is the value of V when Ia=0?

#### jim hardy

Gold Member
2018 Award
V=E–IaRa
Have you taken first year algebra ?

Why does the resistance element become disregarded at no load?
Is multiplication by zero 'disregarded" ?

Is this because the resistance can't cause the voltage to drop at no load?
Bravo !
Most anything when multiplied by zero yields a zero result.

It's important to form that habit because
our minds will believe word constructs that are physically impossible
and that's why they call math "the language of science" .

old jim

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#### Tom.G

Why does the resistance element become disregarded at no load? Is this because the resistance can't cause the voltage to drop at no load?
Yes!
Correct!
You got it!
Good insight!

Carry on with your studies, you passed the first exam.

Cheers,
Tom

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