Transcript EET 270 Midterm Exam Review

EET 270 Midterm Exam Review
What condition does A reflect?
Start Conditions are usually wired
using what kind of contacts.
Sketch a set of Normally Open OffDelay contacts.
What condition does B reflect
Connect the Transformer for 120V
What condition does C reflect
You wish to power a control cabinet controlling motors run by a
480V, 3-Phase circuit. You need to control 4 motors (M.S.
Current=.5A ea), a Safety relay ( .25A) 6 indicators (.1A ea), and 5
Solenoids (.75A ea) using a control voltage of 120V. What
Voltage and Power Rating should the Control Transformer it
have?
What condition does D reflect
Manual Motor Starters are always
used when starting a motor under full
voltage. What is this called?
Connect the Transformer for 120V
Which terminals that would be used to power in
a 240V system (supply and control circuit)?
What condition does E reflect?
Safety devices such as E-Stops,
Light Curtains, and Gate Switches
are normally wired using what kind
of contacts?
What condition does F reflect?
Sketch a set of Normally closed OnDelay Contacts.
What condition does G reflect?
You need to install an overload for a
motor with a name-plate current of
400A. The device used to lower the
sensed current to a manageable level
has a rating of 600:5.
What is this 600:5 device called?
What is I?
Most SSR’s use what device to transmit
information from the input side to the
output side?
What is J?
What condition does H reflect?
What type of relay (with no moving
parts) is commonly used between a
PLC and Motor Starter Coil to protect
the PLC outputs?
What is K?
This device will close when the
temperature is below the set point.
If an optocoupler is going to
control an DC circuit, what kind of
electronic device should be on the
output?
This device will open the rung if a
motor overloads
Lable the Diagram
Sensor Switches that will be used to
control the current to a motor should
have what rating?
Connect the Transformer for 120V
What is the difference between a
contactor and a motor starter?
If a motor draws 10 amps when
running, what current can it draw
when starting?
What should the overloads be set
to if the name-plate current is 12A?
You need manual motor starter that
will not automatically re-start when
power is lost, what characteristic
should you be looking for?
If the Motor Starter is to be placed in a
Control Cabinet that gets hot, while
the motor is in a cooler area, what
specific types of Overloads would be
appropriate?
How much current is the Motor likely
to draw when starting?
Which specific types of overloads
work on the heat due to current
flow through a small heater?
If an optocoupler is going to
control an AC circuit, what kind of
electronic device should be on the
output?
What does an Overload do?
What device is used to sense
motor-current if the current is too
high to measure in-line?
You need to install an overload for a motor with
a name-plate current of 400A. The device used
to lower the sensed current to a manageable
level has a rating of 600:5.
What should the overload current be set to?
Note: you are not setting the OL based on the
actual Motor Current, but on the Secondary
Current
What device is required in any
location that is close to water.
What does it look for and what
does it do?
What is the advantage of an SSR
over an Electro-Mechanical Relay?
What is (PPE) and what kind is
required in lab?
What is the industry-standard method
of reversing the direction of a 3-phase
motor?
What is the difference between
jogging and inching? (action, condition
and time)
Why should the terminals of a Current
Transformer never be left open when
current is running through the wire in
the “window?”
Select the correct wire color for the
given applications.
Connections at Line Voltage
Connects at Control Voltage
Neutral Connections
DC Connections
Neutral connections from another (possibly hot)
panel
Control-Voltage-level connections from another
(possibly hot) panel
What is this?
Identify the following parts of this
device:
Coil
T1-T3 Terminals
Terminals that should connect to
the incoming power
L1-L3 Terminals
Terminals that should be connected
to the motor
Coil Terminals
Mechanical Interlock
NO Auxiliary Contacts (activated by
the coil)
NC Auxiliary Contacts (activated by
the coil)
Overload
Normally Open OL Contact
terminals
Normally Closed OL Contact
terminals
Draw a motor starter circuit for a 480V system with a control voltage of 120V. Include the
following:
___Fused Disconnect, Fused Lines to the motor, Motor Starter Contacts, Current Transformers
and OL heaters and the motor
___A Dual-Primary Control Transformer with primary and secondary fusing and conventional
grounding
___2 stop/start stations
___Run/Jog control.
Do not include an E-Stop Circuit.
Sketch and build Lab 8