208V groups or one three-phase 208V
three single-phase 120V loads and the
group may be served.
To balance this
three single-phase 208V loads should
system, the three single-phase load
be balanced.
groups should be of equal size. A 3
a. Example.
Returning
to
the
4W 120/208V system contains three hot
example of lesson 1, balance
the
wires and a neutral, meaning that
loadings
on
the
The
three single-phase 120V loads, three
following loads were given:
single-phase 208V loads, and a three-
phase 208V load may be served.
The
b. Solution.
The loads should be distributed so that each phase carries an
approximately equal load and so that removal of any one load will still leave
approximately equal loads on each phase.
One possible method of distribution is
shown in figure 5. This results in a distribution as follows:
The ideal situation would be for each phase to carry an exactly equal load but this
is almost never achieved in practice.
Here the loadings on the generator are
balanced to 4.2%
.
This is within the required 10 percent.
2-7
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