Inductance in Coils and Shafts

Any conductor carrying current (and therefore creating a magnetic field) will exhibit inductance.

Yes it is exhibited in any current carrying conductor. It is prominent when conductors are placed in such a way as to concentrate the magnetic field (such as a coil) or when signals are of sufficiently high frequency that the parasitic inductance of ordinary conductors becomes a major concern in propagating the signal.

Hello vscid

As explained by others above, every current-carrying conductor exhibits inductance.

Here is a UHF circuit board, in which the two arrowed printed copper strips act as inductances at the operating frequency.

As you can see, the "strip line" inductors just look like a normal part of the actual printed copper connections.

At 100MHz a hairpin (U-shaped) piece of wire of the dimensions of an ordinary paper clip has an impedance of approximately 100 Ohms, caused by the inductance.

Both transmitting and receiving antennas rely on the relative Capacitance and Inductance of the wire or elements to transmit or receive a signal efficiently.

Kind Regards....

Dear All,

If there is an electrical current, the current induces a magnetic flux.

Inductance is a ratio of this flux (Wb), to the current (A).

So, in any form of conductor, coil or solid shaft, there is a inductance.

A coil has higher inductance the a solid shaft.

Regards

I am CoronaCameraMan -

Are you referring to shaft currents ?

Some, usually synchronous generators or motors can have shaft currents which require one of the shaft bearings to be isolated from the generator frame at the mounting. This insulated bearing housing is difficult to test the quality or integrity of. Without the insulated bearing housing some units will quickly ruin bearings.

Whenever electric current flows, inductance is involved. A gentleman by the name of Frederik W. Grover devoted his career to inductance calculations and wrote a book by that name (ISBN 0-486-49577-9). Between self, and mutual inductance, the book covers any situation you are likely to encounter.

If you are using low frequency, straight lines produce almost no inductive effects unless the current is very high, but I have seen power lines and welding cables move from major short circuits. The comment about bearings being damaged by current ( if you're working with a rotating shaft) is a real concern.

Rebuilt,

What is defined as 'high current' in reference to presence of significant inductance?

For example, we build low frequency resistance welding equipment that delivers 200,000 amperes into a short circuit. At those current levels, nano-henries are important.

Sorry if i confused with my statment. I don't consider " inductance " to vary. Inductive effect implies motion in this case. Considerable current to move wires could be a lot of current like several thousand (or perhaps hundred thousand amps). Sometimes my communications skills let me down.