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In this illustration, however, loads are unevenly divided. A large
number of lighting and small appliance loads are connected to
phase C . This can cause the voltage on phase C to be lower.
Because a small unbalance in voltage can cause a high current
unbalance, overheating can occur in the C phase winding of the
3-phase motor. In addition, the single-phase motors connected
to phase C are operating on a reduced voltage. These loads will
also experience heat related problems.
Transient Voltage A transient voltage is a temporary, undesirable voltage that
appears on the power supply line. Transient voltages can range
from a few volts to several thousand volts and last from a few
microseconds to a few milliseconds. Transients can be caused
by turning off high inductive loads, switching large power factor
correction capacitors, and lightning strikes.
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