CFESA ELECTRICAL ACTUAL FINAL EXAM
QUESTIONS AND ANSWERS
to which terminals on an infinite heat switch should the load be
connected? - ANSWER H1 and H2
to which terminals on an infinite heat switch should a pilot light
be connected? - ANSWER P and L2
Which terminals on an infinite heat switch make and break as
the switch cycles? - ANSWER L2 and H2
Are terminals P and L1 the same connections electrically? -
ANSWER Yes
What will happen if the power line is connected to terminal P -
ANSWER The pilot duty switch contact will melt down
In what voltages are infinite switches available - ANSWER
120,208, and 240 volt
,What does the letter "B" in the model number stamped on the
side of an infinite switch signify? - ANSWER Broiler range
switch
How does the "B" switch operate differently than a regular
infinite switch? - ANSWER More adjustment at the higher heat
range of the curve
When sing an infinite switch, why don't you just connect a pilot
light across the load like you would any other time? - ANSWER
the light will constantly blink and the customer will think there is
a problem
What is the max amp rating of an infinite switch? - ANSWER 15
amps. in a heated area they handle no more than about 12 or
13 amps.
Do infinite switches hold up well when used and the max load
rating? - ANSWER no, the heat derates them
When replacing an infinite switch what else must you do? -
ANSWER replaces the wires and terminals to the switch
,What are the two primary causes for failures of infinite
switches? - ANSWER burned wire connections and excessive
ambient heat
What are the three critical things that must be matched if you
substitute an infinite switch? - ANSWER voltage, regular or
broiler range, and mounting type
What effect does high ambient temps have on a switch? -
ANSWER derates it, cannot handle the marked amperage
If you are servicing a piece of equipment that uses multiple
infinite switches, what will happen if the old switch is "B" rated
and the new one is not? - ANSWER the unit will not heat as hot
as it did with the old switch when the knob is set to the same
position
What will happen if the old switch was not "B" rated and the
new one is? - ANSWER the unit will get hotter than it did with
the old switch when the knob is set to the same position
, The voltage rating of a fuse must always be greater than or
equal to what? - ANSWER The supplied voltage
Which rating on a fuse relates to its ability to prevent an arc
from re striking across the opened fuse element after the fuse
has blown? - ANSWER the voltage rating
A basic rule of thumb for selecting a fuse for a normal
application is to select the fuse at what percent of the full load
current of the application? - ANSWER 125%
What is the difference between an overload and a short circuit
as related to fuses? - ANSWER Overloads melt out the fuse link
in one place, a short opens the link in multiple places
Motor circuits require what type of fuses? - ANSWER Time
Delay
The starting current of a motor can be ow much greater than
the normal full load current? - ANSWER 5 to 6 times
QUESTIONS AND ANSWERS
to which terminals on an infinite heat switch should the load be
connected? - ANSWER H1 and H2
to which terminals on an infinite heat switch should a pilot light
be connected? - ANSWER P and L2
Which terminals on an infinite heat switch make and break as
the switch cycles? - ANSWER L2 and H2
Are terminals P and L1 the same connections electrically? -
ANSWER Yes
What will happen if the power line is connected to terminal P -
ANSWER The pilot duty switch contact will melt down
In what voltages are infinite switches available - ANSWER
120,208, and 240 volt
,What does the letter "B" in the model number stamped on the
side of an infinite switch signify? - ANSWER Broiler range
switch
How does the "B" switch operate differently than a regular
infinite switch? - ANSWER More adjustment at the higher heat
range of the curve
When sing an infinite switch, why don't you just connect a pilot
light across the load like you would any other time? - ANSWER
the light will constantly blink and the customer will think there is
a problem
What is the max amp rating of an infinite switch? - ANSWER 15
amps. in a heated area they handle no more than about 12 or
13 amps.
Do infinite switches hold up well when used and the max load
rating? - ANSWER no, the heat derates them
When replacing an infinite switch what else must you do? -
ANSWER replaces the wires and terminals to the switch
,What are the two primary causes for failures of infinite
switches? - ANSWER burned wire connections and excessive
ambient heat
What are the three critical things that must be matched if you
substitute an infinite switch? - ANSWER voltage, regular or
broiler range, and mounting type
What effect does high ambient temps have on a switch? -
ANSWER derates it, cannot handle the marked amperage
If you are servicing a piece of equipment that uses multiple
infinite switches, what will happen if the old switch is "B" rated
and the new one is not? - ANSWER the unit will not heat as hot
as it did with the old switch when the knob is set to the same
position
What will happen if the old switch was not "B" rated and the
new one is? - ANSWER the unit will get hotter than it did with
the old switch when the knob is set to the same position
, The voltage rating of a fuse must always be greater than or
equal to what? - ANSWER The supplied voltage
Which rating on a fuse relates to its ability to prevent an arc
from re striking across the opened fuse element after the fuse
has blown? - ANSWER the voltage rating
A basic rule of thumb for selecting a fuse for a normal
application is to select the fuse at what percent of the full load
current of the application? - ANSWER 125%
What is the difference between an overload and a short circuit
as related to fuses? - ANSWER Overloads melt out the fuse link
in one place, a short opens the link in multiple places
Motor circuits require what type of fuses? - ANSWER Time
Delay
The starting current of a motor can be ow much greater than
the normal full load current? - ANSWER 5 to 6 times
