You may have heard that you should only use induction
as a last resort. In most cases that’s a good
rule to live by but when you do need to use it, knowing
how is extremely important. There are times when only
induction will help you reduce interference and other
times when using induction is your only option.
In this article we will look at inducing a signal
onto an underground line without a metal to metal
connection.We want to expain what it is, when you
might want to use it, and how to use it to help you
get the results you want.
Introduction to Induction
Induction is the transfer of energy from one circuit
(in this case the transmitter's antenna) to another
(utility) without metal-to-metal contact.
It is another way to make current flow in a circuit
when you cannot make a metal to metal direct connection
to the utility.
There are two ways to induce a current onto a target
utility. The first method is with a clamp, or coupler.
A clamp’s jaws are placed around the conductor
you want to energize, and the other end of the clamp
is plugged into the transmitter. The jaws put out
a signal field which induces a current onto the onto
the target conductor. If you cannot connect directly
to the line this is the next preferred method as you
can place it directly around the target conductor
which helps isolate the line.
The second type of induction uses a coil built into
the transmitter. When positioned over the target utility,
some of the energy emitted from these coils transfers
some of its energy to the utility, causing it to be
energized with the transmitter’s signal.