Is this the default set up of a DC motor?

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Homework Help Overview

The discussion revolves around the setup of a DC motor, specifically focusing on the representation of current direction and magnetic field polarity in diagrams. Participants are examining how these elements relate to the application of Fleming's left-hand rule.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are questioning the clarity of current direction in the textbook diagrams and how it affects the application of Fleming's left-hand rule. There is also a discussion about the interpretation of symbols used to indicate current flow.

Discussion Status

Some participants have provided clarifications regarding the representation of current and magnetic fields in the diagrams. There seems to be a productive exchange of ideas, with at least one participant expressing understanding after receiving clarification.

Contextual Notes

There is mention of potential confusion due to the absence of certain directional indicators in the textbook, which may affect the understanding of current flow and its implications for the operation of the motor.

ellieee
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Homework Statement
in every d.c motor, is it always the case that the current at coil "a" is flowing into the plane and current at coil "d" is flowing out of the plane?
Relevant Equations
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^because in my textbook, the set up doesn't even show the direction of dot/cross at points A/D, so we won't know the direction of current. then how are we supposed to use fleming's left hand rule to determine the direction of force?
 
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I don't understand your question. The current polarity is clearly shown with the battery as well as arrows on the rotor winding. The magnetic field polarity is also shown with N-S labels. The current flows in the plane of the rotor, which is rotating. Then once per cycle, the current switches polarity.
 
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DaveE said:
I don't understand your question. The current polarity is clearly shown with the battery as well as arrows on the rotor winding. The magnetic field polarity is also shown with N-S labels. The current flows in the plane of the rotor, which is rotating. Then once per cycle, the current switches polarity.
oh I see it now thank you !
 
The 'Dot', 'Cross' symbols are taken from how a target arrow (as used in archery) looks when viewed from the end. The 'Dot' is the tip of the arrow coming towards you, and the 'Cross' is the fletching (feathers) on the other end of the arrow going away from you.

Note that this is Conventional Current flow, '+' to '-', Not Electron flow.

Hope this helps!

Cheers,
Tom
 
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