Briggs & Stratton 86262GS Familiarization & Troubleshooting Manual page 17

Portable Generator Familiarization & Troubleshooting Guide
Section 1 • Generator Fundamentals
A 3-phase circuit has the following advantages:
• When the load is balanced in all three legs of a
3-phase circuit, instantaneous power is constant.This
provides better capabilities for motor starting and
running.
• Current flow in a 3-phase circuit produces a constant
flux density, making it more effective than single phase
circuits for starting and running electric motors.
• A wye-connected, 3-phase circuit supplies two
different values of 3-phase voltage in one system.
• To apply 120 Volts to a load, connect it as a
4-wire Wye load, as shown in Figure 1.24.
Figure 1.24 — 4-Wire Wye Load (120 Volts Applied)
• To apply 208 Volts to a load, connect the load in
DELTA fashion (Figure 1.25).
Figure 1.25 — Load Connected In DELTA Fashion
The 3-phase connection systems or circuits may be:
• Wye-Connected
• DELTA-Connected or
• Wye-Connected Re-connnectable (Figure 1.26).
Connections Affecting Circuits
It is necessary to become familiar with some of the terms
used to describe conditions which adversely affect the
operation of electrical circuits. Some of the more common
terms are:
• Open Circuit: An incomplete circuit.
• Partially Open Circuit: A circuit where a high
resistance has developed due to loose or corroded
connections, or a partially broken wire.The resulting
increase in resistance causes current flow to decrease.
• Shorted Circuit: A condition that exists when there is
a DECREASE in resistance across some part of the
circuit. Since electrical current flow "seeks" the path of
least resistance, current will tend to flow across the
shorted section of the circuit.
• Partially Shorted Circuit: A condition where
positive and negative sides of a circuit only contact
slightly, bypassing a small amount of current.
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