[Milsurplus] Electrical question...

[J. Forster]

Ryan Gill wrote:

> Ok, you chaps here seem to understand this stuff pretty well, not
> just what code requires, but why things work the way they do.
>
> In the case of a portable generator system, why does one use a ground
> spike to ground the generator? Does it protect the operator against
> transient voltages that are created by the inductive field of the
> generator?

No. The field is essentially confined inside the machine.

> I was initially under the impression that if you don't
> bond the neutral/ground to earth then you'll not have a complete path
> from the powered equipment and back to the generator and thus
> wouldn't have a hazard if you come into contact with the energized
> hot/neutral wires (unless of course you get between Hot/Hot (in
> 3phase) or between hot and neutral (in 3 or single phase)).

Completing the 'path' or more properly the circuit is the function of the
neutral wire. The ground is to protect the operator in case there is a short or
path in the load or generator from the hot side to the metallic case. The ground
prevents YOU from becoming part of the circuit (and making you dead).

> I've asked an engineer over here at work but, I'm just trying to
> understand the physics behind it all. Based on his explanation, he
> seemed to indicate that your proximity to the generator could amount
> to a localized field that the activity of the generator makes,
> presumably based on the field of the generator windings.

Nope. The fields stay almost completely within the iron and air gap of the
generator.-John

> Am I understanding this correctly?

See above.
-John