Relays Controls and Switching Flashcards
What part of a relay allows for current flow?
Coil
What part of a relay establishes a magnetic field when energized?
Core
What part of a relay moves when energized?
Armature
What does a Normally Closed contact mean?
current flow allowed when de-energized and open when energized
What does a Normally Open contact mean?
No current flow until energized then becomes closed.
What is the purpose of the return spring inside of a relay?
when circuit is de-energized the spring returns the armature to its original position.
Order of operation for an ENERGIZED relay:
- Push Button closed
- relay coil energizes and creates the magnetic field.
- attracts the armature to make contact
- N.O. contacts close to allow current flow
- Lamp / Buzzer/ Load Turns on
Order of Operation for a DE-ENERGIZED relay:
- Push button released
- Relay coil de-energizes
- return spring moves armature back to original position
- Contacts return to N.O. state
- Lamp turns off
What is an UNSUPERVISED circuit?
No current flow (all normally open contacts)
What is an SUPERVISED circuit?
Current constantly flowing (Normally closed contact)
What would happen in a supervised circuit with a buzzer if the neutral was removed/ damaged/ broken?
buzzer would go off constantly
How many terminals does a DPDT switch have?
6
True or False:
On an Ohmmeter if it reads infinite ohms that means that there is Continuity?
FALSE
True or False:
On an Ohmmeter if it reads 0 ohms that means that there is Continuity?
TRUE
How many volts must a doorbell have to function properly
16V or solenoids wont work
What are the various switch operations?
Permanent
Maintained
Continuous
Momentary
Temporary
Can a 4-way switch be used in a 3- way circuit?
yes
On a schematic diagram/ Wiring diagram, what is the colour of the Identified conductor? What terminating screw would it be under?
WHITE
silver screw
On a schematic diagram/ Wiring diagram, what is the colour of the Live conductor?
Any colour you want but normally Black
brass screw (think of ACDC “Back in black” but instead “Black in Brass”)
On a schematic diagram/ Wiring diagram, what is the colour of the Grounding conductor?
Green (Always to Earth (earth, wire and screw are all green))
On a schematic diagram/ Wiring diagram, what is the colour of the switch leg? How is it wired?
Any colour you want but is normally identified with red.
between the initiating device and the load
What colour should the travelers be?
where would it be used in a circuit?
Trick question:
any travelers used should all be different Colours, NO REPEATS!
used only between 2 switches for carrying current.
What are interlocking circuits?
Electrical systems where +2 components are dependent on one anther for operation.
True or False:
Connecting 2 buzzers in series would result in both of them operating at 100% capacity.
FALSE
2 buzzers in series would result in the voltage (assume 120) being divided amongst both of them resulting in a decreased operational capacity.
What would be the best way to install a second load on a circuit with proper functionality?
Parallel
So that the 120 volts are not split between the 2 loads and allow for 100% operation.
What is an Initiating Device?
A control component to start or stop the entire flow of electricity in the circuit.
