Elementary/Logic Diagrams Flashcards
What is a 33 Device Number?
Position Switch
What is a 43 Device Number
Manual Transfer Switch. (Still a type of control switch)
What is a 49 Device Number?
AC thermal relay or device. (Thermal overload)
What is a 50 Device Number?
Overcurrent Relay or Device. (Instantaneous)
What is a 51 Device Number?
Overload Relay (time delayed)
What is a 52 Device Number?
AC Circuit Breaker.
What is a 62 Device Number?
Time Delay Relay
What is a 63 Device Number?
Fluid Level, Pressure, or Flow Relay
What is a 72 Device Number?
DC Circuit Breaker
What is a 87 Device Number?
Differential Current Relay
What is a 88 Device Number?
Motor Starting Contactor
What is a 101 Device Number?
Control Switch
What is Shelf Condition?
Relay contacts shown in the de-energized condition unless otherwise noted.
What is an ‘a’ contact?
Normally OPEN when de-energized.
What is a ‘b’ contact?
Normally CLOSED when de-energized.
Describe Lights colors and meanings in a control circuit.
1: Green means breaker is OPEN.
2: Red means breaker is CLOSED.
3: White could mean different things (examples: permissive, or component is operating hot).
What is anti-pump and what is it for?
Prevents a breaker from re-closing when a breaker trip signal and close signal exist simultaneously.
Also prevents BKR closure when charging motor is not charged or BKR is not in TEST or CONNECT.
Prevents overheat and damage in BKR.
Explain the importance of the “Abnormal or Locked-out” alarm on a safety related pump breaker.
VERY IMPORTANT!
What is a 5 Device Number?
Stopping Device.
What is a 27 Device Number?
AC Under Voltage Relay.
For real, Explain the importance of “Abnormal or Locked-out” alarm on safety related pump breaker.
Locked out is used for safety/protection. Both Abnormal and Lock out will give an alarm.
Possible Causes for alarm:
1: Control Switch in Lockout.
2: Breaker not fully racked in.
3: BKR charging spring not fully charged.
4: BKR control fuses blown/pulled.
What is an Off- Return Memory device?
Produces an output when an input is present. The output remains until removed by reset signal. A loss of power also acts as a reset signal.
Symbol is a square with a wye in the middle.
What is a retentive memory device?
Retains condition of output based on last energized input (regardless of power interruption). When power is lost/restored, output remains until reset.
Symbol is square with vertical line up middle. Left/Right boxes are empty.
What is a Retentive Memory with Actuation Block device?
Device wit retentive memory and also includes a function to block the actuation signal by resetting the signal. When reset with the actuation signal present, the device remains reset until the actuation signal goes away and then comes in again.
Symbol is a square with a vertical line up the middle. The boxes have L and R in them (Latch/Reset)
