Hvac Test March Flashcards
Where does supply air go?
To the structure
What is Ohm’s law?
E over I R
To replace a contactor you need _______.
Number of poles, fla, coil vac
Fla means _______.
Full load amps
RES means _______.
Resistive amps
Rla means _______.
Rated load amps
Lra means _______.
Locked rotor amps
Component for Lra is _______.
Compressor
Another term for Lra is _______.
Inrush current
Info needed for replacing a motor includes _______.
Rpm, hp, vac, amps, rotation, frame size
Where does the set screw go?
Flat side
Which weep hole is removed?
The bottom
When replacing a motor you replace _______.
Capacitor / CAP
When do you leave fan motor wire over the grill?
Never
When replacing a condenser motor what should you measure?
Fan blade position
How do you cut the shaft?
Reciprocating Saw, Angle Grinder, Hacksaw
On a uni motor with 2 brown wires, where do they go?
Each side of the capacitor
The same leg that power run winding powers the _____
C on Cap
C on the dual cap stands for _______.
Cap power in / same as run
Common of the motor wires goes to _______.
Opposite of run
When does common go to capacitor?
Never
What’s fan on a dual cap?
Fan start winding
What’s herm on dual capacitor?
Compressor start winding
Before checking capacitor you need to _____
Turn off power / check for no voltage / discharge w/a 20K Ohm 5-watt resistor, isolate capacitor, then check w/meter
A run capacitor is made of _______.
Metal
A start capacitor is made of _______.
Plastic
A run capacitor should be mounted _______.
Secured with metal strap upright
Can you replace a dual capacitor with two single run capacitors?
Yes
Can you replace a 370 vac capacitor with a 440?
Yes… up but not down
Can you replace a 440 vac capacitor with a 370?
No must be 440
A start capacitor must have a _____
Potential relay
With number 86 they make a _______.
Hard start kit
Start cap and its components are wired how?
5=C 2=S 1=R
Symbol for capacitor is _______.
——| C-‐—-
Capacitors are measured in _______.
Microfarads
Abbreviation for mfds is _______.
UF
System is running but you read 28vac between L1 and T1, what does that mean?
Voltage drop
What’s the lowest ohms points in a compressor?
C&R
What’s the highest ohm points in a compressor?
S&R
R&S=8Ohms, R&C=OL, S&C=OL. What does this mean?
Full on Ito
1 most replaced part is _______.
Capacitor
2 most replaced part is _______.
Contactor
3 most replaced part is _______.
Condenser fan motor
When a motor is pulling more amps than what it’s rated for, it’s called _______.
Overamping
What tool can be used to check insulation on a motor winding?
Megohmeter
