Systems Controls And Schematics Flashcards
What is a relay
An automatic or remote control device that uses one or more initiating devices to operate another device on the same or another circuit
The contacts of a relay may have DC as well as AC voltage ratings
What does TDOE stand for, what does it do
Time delay on energization, when contacts change only after a specified time, measured from the instant the relay is energized.
What does TDOD mean
Time delay on de-energization. Contacts change instantly when a relay is energized but will revert back only after a specified time when relay is de-energized
2 types of capacitor
Run (power capacitor)
Start (motor starter capacitor)
Capacitors are used for?
To increase the running efficiency of the motor or to give a boost in torque start-ups.
What is capacitance
The ability of an electrical device to store energy into an electrostatic field and release that into an electrical circuit
Capacitor has a rating of one_____
What is it converted to because it’s to large of a unit
Farad, and microfarad which is 1millionth of a farad
Start capacitor rating? With what 3 major voltage classifications?
70mfd and above, 125v,250v and 330v
What is the insulator of a capacitor called what types are there
Delectrics, air, paper, ceramic
What is an IDM and where is it connected
Induced draft motor, wired in series with the gas valve control unit
What does an IDM do
Draws required amount of air through heat exchanger, assists the flue gasses to rise up through vent, leaving vent in a negative pressure
The flame rollout switch is?
A high temp limit located on top of the burner box detected any flame blow back or roll outs.
High limits temp range, can it be adjusted.
Temp range is 180°f to 200°f, it cannot be adjusted as it is factory calibrated
Should high limit switches be bypassed to put heating system back in operation?
Under no circumstances should it be bypassed
What is an HSI and what does it do?
Hot surface igniter, it lights the gas flame upon unit start up, electricity flows causing surface to heat up to approx 2600°
What is flame rectification?
An electronic way to prove flame is burning
What type of current comes from a flame sensing unit up to the electronic board?
The current is rectified (changed) from AC volt to DC microamps
What is an HPS and what does it do?
High pressure switch for the compressor and refrigeration circuit monitors the system for an inoperative outdoor motor or dirty/restricted condenser
What is an LPS and what does it do
Low pressure switch monitors refrigeration system for a loss of refrigerant charge, helpful in stopping evaporator or indoor coil freezing
Run capacitor are rated, what is the voltage classification range
In 3-70mfd, 370V or 440V
What is SPST-NO
SPST-NC
SPDT
DPDT
Single pole single throw- normally open
Single pole Single throw- normally closed
Single pull double throw
Double pole Double throw
What is SPST-NO
SPST-NC
SPDT
DPDT
Single pole single throw- normally open
Single pole Single throw- normally closed
Single pull double throw
Double pole Double throw
What are pressure switches and what do they do.
A safety device connected to the IDM, they prove the idm is running and that there is no blockage in vent system
