I 1 And I 2 Flashcards
Besides start and stop, a motor starter also provides
Overload protection
3 types of manual motor starters
Toggle, push button and drum
The hp of the starter must exceed what?
The hp of the motor
What part of a simple manual motor starter senses overload?
Overload relay OLR (heater)
Melting type of thermal overload is a
Solder pot relay
Bi metallic strip overload relay uses what
A strip of two dissimilar metals
What is low voltage protection
A control device that drops out on low voltage but won’t pick up once voltage is restored
Toggle switch is good for how may hp?
One
Drum switch is good for how many hp?
3hp @ 240
1hp @ 120
Push button switch is good for how many hp?
5hp @ 230v
List 3 methods when guarding the exposed live parts of a motor
Electric room
Elevate beyond 2.5m above the floor
Fence
2 important safety steps you must take before starting work on a motor branch circuit
Disconnect power source
Lock out and tag out
How can you protect your face and eyes from atc flash when closing a motor switch?
Turn your head when operating switch
Before you energize motor, test with a
Megger
Besides shock, a motor presents what kind of hazards that can be reduced by using?
Mechanical
Guards
Three functions other than start and stop for a motor controller
Running protection
Reverses rotation
Varies the speed
The difference between magnetic contactor and magnetic motor starter
The starter has overload protection
Difference between power circuit and control circuit or a starter?
Power circuit= main line contacts
Control circuit=electro coil and aux contacts
2 parts of a thermal overload relay
Heater element
N/c aux contacts
3 phase motor requires a what in series with each line?
Overload heater
Selection of the overload heater is based on
Full load current of motor
Before you can reset an OLR you must
Give it time to cool
Stops are always
Series
Starts are always
Parallel
Two wire circuits
Release
3 wire circuits
Protection
Release
The motor will restart after voltage returns
Protection
The contacts open and will not start again until manually reset.
Pilot light
Indicate operation from another location
Show status of motor
4 components in the power circuit of an across the line mag starter
Disconnect switch
Over current protection
Hp rated contacts
OLR
2 components in the control circuit of a mag starter
Magnetic starter coil
OLR aux contacts
Push buttons
2 wire control
Maintained contact devices
3 wire control
Momentary contact devices
What is full voltage control
Control circuit has the same voltage as the power circuit.
What hazard can occur using a simple job button with start stop
The motor may still continue to run.
How do you fix the problem with a simple jog?
Create a definite break by including a 2 position jog run switch
What’s the difference between a 3 phase reversing mag starter and a Non-reversing?
The reverse has (2) sets of 3 pole contactors
Carter could be caused by
Broken shading coil
Poor connection in control circuit
Low voltage.
