Quizzes Flashcards
AC motors have _________ inrush current
Large
Name two types of switches for motors?
toggle switch, knife switch
What type of rating must all switches for motors be?
hp rated
The starter is connected in __________ with the supply line and the motor terminals
series
Switches for motors are normal for what amount of hp? and voltage?
1hp @230v
Push bottom starters are used for a maximum of what hp? and voltage?
5hp @230v
What are the ratings of a drum switch?
3hp @ 240v , 1.5hp @ 120v
What is the drum switch used for?
used to control speed
What does the drum switch not have?
overload protection
name two types of overload relays?
bi-metallic and metallic-alloy
What is it called if you need your motors to restart automatically after power returns?
low voltage release
What is it called if you don’t want the motors to restart automatically after power returns?
low voltage protection
Motors have both ________ hazards and __________ hazards?
electrical
mechanical
How can you protect your face and eyes from arcs and flashes when you close a motor switch?
turn your head and face away
What is locked rotor current?
Large current drawn when motor is jammed
Why are motor switches hp rated?
to safely interrupt inrush currents (3-6x large than running current)
What does it mean by “across-the-like-starter”?
starts at full motor voltage
What is a manual motor starter?
started contacts are opened and closed manually
What is a magnetic motor starter?
starter whose contacts are open and closed electromagnetically
what does a dotted line mean?
mechanical connection
what devices in a power circuit must be hp rated?
disconnect switch, power contacts, motor
what device will stop and start the motor?
power contacts
An overload relay that has two dissimilar strips of metal is called?
bi-metallic relay
What stops and starts the motor?
power contacts
