motor controls
10A
16 AWG control conductors that extend beyond the motor control equipment enclosure must be protected with protection device rated no more than
one
NEC typically requires___overload relay units for every ungrounded conductor
control circuit
The circuit of a control apparatus or system that carries the electric signals directing the performance of the controller but does not carry the main power current.
H
When wiring a control transformer for a 3 wire control circuit the higher voltage terminals typically have a letter___with the terminal numbers
False
a 3 wire control circuit has built in low voltage
motor controller
a ______ is any switch or device that's normally used to start and stop a motor by making and breaking the motor circuit current
series circuit
a circuit in which all components or contact symbols are connected end to end as in a continuous loop providing only one path for current flow
LS
a common abbreviation for a limit switch
relay
a device operated by a change in one electrical circuit to control a device in the same circuit or another circuit
control circuit transformer
a device used to supply reduced voltage to a control circuit
not greater than the largest rating or setting of the
a feeder supplying fixed motor loads shall have a protective device with a rating or setting____branch circuit short circuit and ground fault protection device for any motor in the group plus the sum of the full load currents of the motors of the group
300v
a general use ac snap switch can be used as a motor disconnect or controller for stationary motors rated 2 hp or less and _____or less providing the requirements of 430.83C OR 430.109C2 of the NEC are met
a or b
a horsepower rated___having a horsepower rating not less than the motor rating shall be permitted to serve as the disconnecting means
selector switch
a manually operated switch that uses a rotating motion for actuating a device
all of these
a motor can be provided with combing overcurrent protection using a single protective device to provide brand circuit___protection where the rating of the device provides the overload protection specified in 430.32
switch
a motor control circuit for the most part is simply a ____ and a motor
False
a motor controller shall open all conductors to the motor where not used as a disconnecting means
true
a remote control circuit is any electric circuit that controls any other circuits through a relay or equivalent device
a and b (not taken from the branch circuit feeding the motor and typically a class 1 control circuit)
a separate control circuit is
toggle switch
a standard on off wall mounted snap switch used for most lighting outlet is an example of
heater
a very common type overload device is a eutectic alloy thermal overload. This type of overload device is sometimes called
power from the transformer
in thermostat conductor termination the color red is typically used for
all of these
its possible for. motor to become so hot that it will burn out or stat a fire. A common cause of overload is
A or b (line diagrams or elementary diagrams)
ladder diagrams are also known as
any of these
lamps are commonly used in pilot lights
heat and current
many types of overload protectors operate on the relationship between
low voltage protection
means that if power goes off to the control circuit the equipment won't automatically restart when power is restored
true
most three phase motors are used in commercial and industrial applications
500
motor controll circuit transformers with a primary Current rating of less then 2A can have the primary protection device set at no more then___percent of the rated primary current rating
300
motor controller circuit conductors that extend beyond the motor control equipment enclosure shall have short circuit and ground fault protection sized not greater than___percent of value specified in table 310.15B16 OR 60
true
motor controllers and terminals of control circuit devices shall be connected with copper conductors unless identified for use with a different conductor
true
overcorrect protection us always required on the primary side of a control transformer unless it will create a hazard such as for the control circuit for a fire pump motor
rises slowly and has long duration
overload current
600
overload relays have 10 seconds 20 seconds or 30 seconds ratings. These ratings are the maximum second an OL takes to trip at ____percent of its current rating
plugging reversal
pressing either the forward PB or the reverse PB to reverse direction while the motor is already running causes stress in the motor and briefly cause high current which produces abnormal heating in the motor this called
16v
residential type doorbell circuits are typically
true
schematics show motors and control equipment in their resting or shelf state
a or b
selector switches use_____ to show the position of the switch contacts in relation to the switch position
true
sequence control is method by which the control circuits of magnetic starters are interconnected so that one must be started before the second one is energized
true
short circuit or ground fault current is many times higher than running current and must open the protection device as quickly as possible to minimize the damage
all of these
some chimes
False
switching devices such as float switches limit switches or relays always come with only one set of contacts
branch circuit
the circuit conductors between the final over current device and the outlet or equipment
close
the disconnecting means for a motor controller shall be designed so that it can't ___automatically
starting
the motor branch circuit short circuit and ground fault protection device shall be capable of carrying the __current of the motor
Lower than
the motor controller shall have horsepower ratings at the application voltages not ____the horsepower rating of the motor
plainly indicate
the motor disconnecting means for a motor shall___whether it is in the open(off) or closed(on) position
all of these
the motor disconnecting means shall not be required to be in sight from the motor and the driven machinery location provided
a terminal
the point at. which an electrical component is connected to another electrical component
true
there no standard color code for the use of pilot indicator lights
twice as much current
when connected at the lower voltage and a dual voltage three phase motor draws___then when connected at the higher voltage
reverse
when the selector switch of a forward reverse control circuit is in the ____position the forward portion of the circuit is disconnected
true
a wye/delta connected motor is commonly used where reduced inrush current starting torque is needed
true
in a magenetic motor starter when the coil is energized a NO set of contacts will close and a set of NC contsttcs will open
true
in many cases equipment for control and signaling comes with the manufactures instructions
SSW
A common abbreviation for a safety switch
16
AWG control conductors located within the equipment enclosure are protected by the branch circuit overcorrect device if its rated 40A or less
mechanically held
a____ contractor has two coils and maintained contact power contacts and is similar to a simple toggle switch in that its ON in one position and OFF in the other position
a nd b
a____rated in amperes shall be permitted as a controller for all motors
a and b
according to NEC a common tapped control circuit can be protect by
18
according to NEC control circuit conductors can be as small as ____AWG
contractor
an electromechanical device used for repeatedly establishing and interrupting an electric power circuit
doesn't exceed 1000v
an oil switch can be used as both the motor controller and disconnecting means on a circuit whose rating____or 100A
pictorial diagrams
are used mostly in educational materials and as exploded views or cut away views in installation and maintenance literature
ladder diagrams
are used to represent the function of the control circuit and the associated devices but don't show the components of the control circuit in their actual positions
125
conductors supplying several motors shall not be sized smaller than___percent of the full load current rating of the highest rated motor plus the sum of the full load current ratings of all other motors in the group plus the ampacity or other loads
true
connection diagrams are also called wiring diagrams
true
contactors don't provide overload protection
False
drum switches provide motor overload protection
25
feeder tap conductors supplying motor circuits with an ampacity at least one third that of the feeder shall not exceed ____ft in length
true
for a class 1 control circuit used as a separate control circuit control conductors 14 AWG and larger are protected at their ampacity
NEC table
for general motor applications the motor branch circuit short circuit and ground fault protection device shall be sized based on the ___values
24v and 600v
for motor control applications the relay coil voltages are typically rated between
80
for stationary motor of 2 hp or less and 300v or less on ac circuit the controller can be an ac rated only general use snap switch where the motor full load current rating is not more than___percent of the rating of the switch
horse power
if a motor disconnecting means is a motor circuit switch it shall be rated in
true
illuminated doorbell buttons can be wired in the same way as doorbell buttons that aren't illuminated
the same as that of the higher voltage
in a dual voltage three phase motor the VA of the motor if connected for the lower voltage is
3 wire
whenever a control circuit makes use of holding contacts that drop out on power loss its called a _____circuit regardless of the actual number of conductors necessary to provide for all circuit options
a and b
where a dual voltage control transformer is used and the control circuit is 120v on the secondary the
true
where more than one motor disconnecting means is provided in the same motor branch circuit at least one of the disconnecting means shall be readily accessible
all of these
which of the following can be considered a motor controller
all of these
which of the following can be considered control devices rather than motor controllers
all of these
which of the items can be considered a manual control with
