DC motor series excitation self-regulating power

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Hi friends,

how can we demonstrate that in a specific area, a DC motor series excitation becomes self-regulating power???

et thank you,
 

Hello Dear Essadaoui_Red
the torque of a DC motor considered about infinite . so if you put a heavy load , thus it will increase the current , thus it can carry it . and if you decrease the load thus it , will decrease the current .
remember that a motor , without kept ( suppose that you kept it with your hands , it will increase the current) . considered as a short circuit because the diagonal force , need opposition , if it will be constant , thus , you wont have an opposition , and thus the current will increase ( refer to the lenz and lorance law )
I hope that i correctly understood your question.
Best Wishes
Goldsmith
 


thank you,
but i think we have to demonstrate that the electromagnetic power varies little with the load, and with a good aproximation, i'll have constant electromagnetic power in a spécific earea, that means my DC motor series excitation becomes self-regulating power...
but i can't prove it realy !!:sad:
 

at the self regulating power , the flux coil is in parallel with a variable resistor , are in series with the main power line . so you can solve it as an electrical circuit , ( RL circuit . ) isn't it ?
Regards
Goldsmith
 

goldsmith said:
at the self regulating power , the flux coil is in parallel with a variable resistor , are in series with the main power line . so you can solve it as an electrical circuit , ( RL circuit . ) isn't it ?
Regards
Goldsmith
Click to expand...

in DC Motor series excitation, the flux coil is in series with variable résistor in series with the main power line,
i've U = E + (Rind +Ra) I
Torque: Tem= k * I²
électromagnetic power :Pem= E*I = Tem*w -- w : speed
with all this i can't prove that Pem = cte in a spécific erea (with a good aproximation),
ok tank's
 

But i think it is in parallel , because if it is in series , it will limit the out put current and it it will increase the dissipation .( as i can remember )
Good luck
Goldsmith
 

goldsmith said:
But i think it is in parallel , because if it is in series , it will limit the out put current and it it will increase the dissipation .( as i can remember )
Good luck
Goldsmith
Click to expand...

hi,
in series excitation, all in series, it's a king of DC Motor excitaion, (there are others arallal , compound and separate excitation).
I just find the solution this morning :idea:
When the load increases, the current increases, therefore the excitation increases (same current), so the speed decreases for the same voltage.
Hopefully, the power is almost constant:
ok tank's :-|
 


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