Product Manual

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Motor Starters
As their name implies, motor starters apply electric power to a motor to
begin its operation. They also remove power to stop the motor. Beyond
merely switching power on and off, starters include overload protection,
as required by the National Electrical Code. The code also usually requires
a disconnect and short circuit protection on motor branch circuits.
Fused disconnects and circuit breakers provide this and are often
incorporated into a motor starter enclosure, resulting in a unit referred to as a
combination starter.
Across The Line Starting of Induction Motors
• An across the line starter is the least expensive option and is usually
used for induction motors.
• All NEMA design induction motors up to 200 HP, and many larger
ones, can withstand full voltage starts.
• Manual starters are often used for smaller motors - up to about 10 HP.
They consist of a switch with one set of contacts for each phase and
a thermal overload device. The starter contacts remain closed if
power is removed from the circuit and the motor restarts when
power is reapplied.
Three-Phase
Motor
Manually Operated
Contacts
Overhead
Heaters
Figure 4.1
Manual Starter