Rail Gun: Why use Positive Sign Convention?

[justadream]

From wiki:

When considering the function of a rail-gun, why do we use the positive sign convention for current?

In the actual operation of the rail-gun, electrons are flowing right?

Thus, is the ACTUAL flow of current always opposite what is depicted in rail guns?

---

Members don't see this ad.

 

[IslandStyle808]

Hmm.. Not sure I always thought the rail gun had a battery set up where the current flows from the positive terminal to the negative. This should dictate the direction of the current.

 

[sillyjoe]

From wiki:

When considering the function of a rail-gun, why do we use the positive sign convention for current?

In the actual operation of the rail-gun, electrons are flowing right?

Thus, is the ACTUAL flow of current always opposite what is depicted in rail guns?

That is just how the convention works. Unless they specify electrons, current is ALWAYS positive. Always always.

It might be easier to look at the rail gun situation just by knowing that the flux = B*A. (B = magnetic field / A = area). For example, if you turn down the applied magnetic field to a rail gun, the system will want to bring back the flux. How can the system do that in a rail gun?

Well flux = B*A, and when you decrease B, the system will increase A, meaning the rail will be "pushed" forward by the force to increase the area and bring back the lost flux.

The right hand rule is generally great, but it is definitely a more challenging way to look at a rail gun as opposed to flux = B*A.