Transcript Overload

• Function of a motor starter:
• To ? starting and ? a motor.
• Provide motor ? from overload conditions.
• Function of a motor starter:
• To control starting and stopping a motor.
• Provide motor protection from overload conditions.
NEMA ~ National Electrical Manufacturing Association
NEMA ~ National Electrical Manufacturing Association

NEMA starter have heavy duty contacts. Good for applications when many start and stops
are required in a short period of time.
NEMA ~ National Electrical Manufacturing Association


NEMA starter have heavy duty contacts. Good for applications when many start and stops
are required in a short period of time.
This device is also termed a cross the line starter.
NEMA ~ National Electrical Manufacturing Association


NEMA starter have heavy duty contacts. Good for applications when many start and stops
are required in a short period of time.
This device is also termed a cross the line starter.
 Meaning that the full 480 volt line voltage is applied to a motor the instant the coil is
energized.
NEMA ~ National Electrical Manufacturing Association




NEMA starter have heavy duty contacts. Good for applications when many start and stops
are required in a short period of time.
This device is also termed a cross the line starter.
 Meaning that the full 480 volt line voltage is applied to a motor the instant the coil is
energized.
NEMA Size 1: Can handle full load currents up to a 10HP 480 Volt motor.
NEMA Size 2: Can handle full load currents up to a 25HP 480 Volt motor.
NEMA ~ National Electrical Manufacturing Association

NEMA Size 4 starter.
NEMA ~ National Electrical Manufacturing Association


NEMA Size 4 starter.
A separate control relay is required to energize the coils of these large starter units. Current
from a PLC output card is to small for the inrush amps that the large coils require.
AB Size 4 Starter
IEC ~ International Electrotechnical Commission
IEC ~ International Electrotechnical Commission
Reversing Starters
•A reversing starter is mechanically interlocked for safety. Only one set of motor
contacts can be closed at one time. This prevents two phase lines making contact
with each other.
• Components of a motor starter.
• Coil.
• 120 volts AC or 24 volts DC
• Can be replaced on NEMA units.
• Components of a motor starter.
•Heavy duty contacts.
• Contacts used to carry heavy current loads.
• Components of a motor starter.
•Control contacts that are called auxiliary contacts.
• Small contacts that can be mounted on side of starter.
N.O. or N.C.
• Used for hold-in, indicator lights, feedback.
• Components of a motor starter.
•Overloads.
• Sized to FLA rating of motor nameplate.
• Overload contacts.
• NC wired in series with coil.
• NO wired for feedback to PLC or indicator lights.
• Overload:
• Protects the motor when it draws current greater than the full
load amp (FLA) rating but less than the motors locked rotor
current.
• Check device that motor is driving.
• Gear box, pulley, conveyor belt, fan, etc..
• Overload:
• Protects the motor when it draws current greater than the full
load amp (FLA) rating but less than the motors locked rotor
current.
• Check device that motor is driving.
• Gear box, pulley, conveyor belt, fan, etc..
• Locked Rotor Current:(LRC)
• Current draw by motor when motor shaft is stationary.
• Overload:
• Protects the motor when it draws current greater than the full
load amp (FLA) rating but less than the motors locked rotor
current.
• Check device that motor is driving.
• Gear box, pulley, conveyor belt, fan, etc..
• Locked Rotor Current:(LRC)
• Current draw by motor when motor shaft is stationary.
• Overcurrent:
• When motor current is greater than LRC.
• Fuses or circuit breakers are sized to trip when a overcurrent
is detected.
•Time to get out the ____?___ meter and check for a bad motor winding.
• Overload:
• Protects the motor when it draws current greater than the full
load amp (FLA) rating but less than the motors locked rotor
current.
• Check device that motor is driving.
• Gear box, pulley, conveyor belt, fan, etc..
• Locked Rotor Current:(LRC)
• Current draw by motor when motor shaft is stationary.
• Overcurrent:
• When motor current is greater than LRC.
• Fuses or circuit breakers are sized to trip when a overcurrent
is detected.
•Time to get out the Megger meter and check for a bad motor winding.
NEMA ~ National Electrical Manufacturing Association
AB Motor Starter Bucket
Enclosure that houses motor controls and circuit protection.
Starter, Lockout, Fuse Disconnect, Overloads
AB Motor Starter Bucket
Back side of starter bucket.
AB Motor Control Center
Large electrical enclosure that houses motor control buckets.
Load Center
Location in a facility where all incoming electrical power is routed too.
Room will house large distribution transformers. 4160 Pri, 2000KVA, 480 Sec.
Room will house multiple MCC that will distribute power out to production
equipment.
Room will also house large circuit breaker distribution panels.
Typical 3 Wire Starter Control Schematic
Typical Control Motor Starter Wiring Schematic
Typical E-Stop/Jog Hardwiring Control Schematic
Typical E-Stop/Jog Hardwiring Control Schematic