Ch. 15
The stationary part of a motor.
The type of fuse that blows immediately upon reaching its rated current.
what is a fast-acting fuse?
This diagram shows approximate location of devices, wire colors, and connections among devices.
What is a pictorial diagram?
Typically the culprit of a distinct knocking noise in a motor.
what is excessive endplay?
The first thing a technician checks when starting diagnostics.
what is main power?
The part of a motor that houses bearings
what is the end bell?
The numbers in a control system that include cut-in and cut-out values.
What is range?
An unbroken path within a circuit will have this.
what is continuity?
The change in motor speed when a variable pitch pulley tightens up.
what is motor speed increases?
If not currently installed on a single phase motor, a technician can add this to help reduce LRAs.
What is a start capacitor?
The difference in a motors synchronous speed and its rated full load speed.
what is slip?
The actual point (typically temp., psi., or humidity) a sensor senses in a space.
what is control point?
This is represented by the horizontal lines on a ladder diagram.
What is a circuit and a load?
This occurs when 1 leg of power is lost in a 3 phase circuit but the load(s) still attempt to operate.
What is single phasing?
How a technician determines unmarked terminals on a single phase motor.
what is check the resistance (com - run, lowest ; com - start, middle ; run - start highest and must equal total of com - start + com - run)?
The names of the terminals in a single phase motor
what is common, start, and run?
The device that functions range adjustment in an electronic controls system.
What is the processor?
The range in value between true power and apparent power.
What is 0 - 1 (or 0% - 100%)?
The hottest part of a motor should not be greater than this temperature.
what is 72 degrees F?
The two major types of communication signals used in a DC control circuit.
What is 0-10vdc and 4-20mA?
The two things that determine an AC motors speed.
Four factors that cause an oil pressure motor control to trip.
what is Incorrect oil level in the compressor, improper tubing size, unbalanced system, low refrigerant charge, refrigerant migration, improperly set control, electrical problems, and compressor malfunction.
Four things an HVAC digital multimeter can read.
What is volts, current, capacitance, frequency, resistance, diodes, temperature?
Three causes of motor failure.
what is Overuse, age, the development of internal problems (cannot dissipate heat due to dirt, poor lubrication, bearing failure), continuous running because it is undersized, a slipping or excessively tight belt?
The number one reason technicians struggle to solve problems in the field.
What is overthinking/doubting themselves?