J 1 and 2 Flashcards
Define: LRC
locked rotor current
Toggle switch starters are rated for ____ HP
1
Two types of thermal overloads
Melting-alloy overload rely (solder pot)
Bimetallic strip overload relay
Three ratings for manual motor starters
voltage
horsepower
ampacity
Define: Low-voltage protection
provide with magnetic motor starters.
when the power is lost the magnetic contacts open up and when power is restored the contacts will not close
three wire
Define: Low-voltage release
two wire starters that use maintained contacts
when the power goes out the motor will stop but when power is restored the motor will start automatically
Some functions of a motor starter
Reversing Speed control Sequencing control Remote control operation Operator safety
A basic magnetic starter
contactor
overload relay
Magnetic contactor has a
laminated core
moveable part called a armature
armature closes a set of normally open contacts
The OLR has two basic parts
heater element
N.C auxiliary contact
Power circuit consists of
disconnect switch
hp-rated contacts
OLR heaters
motor
Control circuit consists of
Switch
Sealing contact
Coil
OLR contacts
Two-wire control circuit provides
low-voltage release
and use maintained contact initiating devices
Three-wire control circuit provides
low-voltage protection
and use momentary contact initiating devices
Stop buttons are connected in
Start buttons are connected in
series
parallel
