- #1
Telemachus
- 835
- 30
Homework Statement
Hi there. I have to solve this problem, and I'm having some doubts.
It is desired to build an electric engine of 0.9[HP], which will be connected to 220[V]. This will be done by a Cu wire with a cross section of 1.2 [mm²]. Supposing an efficency of 90% compute how long should the wire be.
The Attempt at a Solution
Well, I wasn't sure on how to consider the circuit for this. I thought of putting the engine with a resistor in series. Then I have:
##R=\rho_Cu \frac{L}{A}##
##P=IV##
##V=IR##
I wanted some guidance for this, because I'm not totally sure on what to do. I think that the exercise can be donde in a variety of forms, I thought of using a resistance in parallel, but I don't know if that would be fine. I thought of considering one resistance corresponding to the wire that goes from the battery to the engine, and then another resistance corresponding to the wire going from the engine to the battery again, and that would complicate things too much I think, because the configuration of the series resistances would depend on how long is the wire in each part.