seal-in is not a hotel in monterey this presentation is partially animated. only use the control...
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Seal-in is not a hotel in Monterey
This presentation is partially animated. Only use the control panel at the bottom of screen to review what you have already seen. When using your mouse, make sure you click only when it is within the blue frame that surrounds each slide.
Your comfort level with your responses to the following 2 question assessment tool should indicate if the presentation that follows will increase you knowledge base on the topic outlined by the questions in this tool.
Pre-presentation Self Assessment Activity
Pre-presentation Self Assessment Activity
2) The following diagram indicates that the relay circuit controlled by MR1 is energized after the pushbutton has been pushed and then released.
yes
no
PB 1LB 1 MR 1 M1
CR 1
1) Draw a ladder circuit diagram that will show the wiring of a normally open push button such that pushing the button will seal in a motor relay contact set, MR1.
Auxiliary contacts for
seal in circuits
Relay review
0
voltmeter
+
NO
0
currentmeter
A normally open push button.
Inductor with a ferromagnetic core
light bulb with an incandescent filament
Relay review
0
voltmeter
+
NO
0
currentmeter
Magnetic field lines indicate presence of a magnetic field
When current flows a magnetic field is generated around the flowing electrons.
Note:(a) This magnetic field is also called an electromagnetic field. (b) However, this magnetic field is the same magnetic field as the field made by two bar or a single horse shoe magnet
Relay review
0
voltmeter
+
NO
0
currentmeter
NO
+
0
currentmeter
Relay review
0
voltmeter
+
NO
+
0
currentmeter
NO0
currentmeter
Relay review
0
voltmeter
+
NO
+
0
currentmeter
NO0
currentmeter
Relay review
0
voltmeter
+
NO
+
0
currentmeter
0
currentmeter
NO
Circuit ladder Diagram
0
voltage
+
NO
0
Current
+
0
current
NO
relayCartoon of circuit
Ladder diagram of circuit
0
voltage
Circuit ladder Diagram
0
voltage
+
NO
0
Current
+
0
current
NO
relayCartoon of circuit
Ladder diagram of circuit
0
voltage
PB 1
PB 1
LB 1
LB 1
Circuit ladder Diagram
0
voltage
+
NO
0
Current
+
0
current
NO
relayCartoon of circuit
Ladder diagram of circuit
0
voltage
PB 1
PB 1
LB 1
LB 1 LB2
LB1 = light bulb #1LB2 = light bulb #2PB1 = push button #1MR1= Motor contacts #1M1 = Meter #1M2 = Meter #2
MR 1 M1
MR 1
M1M2
Circuit ladder Diagram
0
voltage
+
NO
0
Current
+
0
current
NO
relayCartoon of circuit
Ladder diagram of circuit
0
voltage
PB 1
PB 1
LB 1
LB 1
MR 1
MR 1
M1
M1M2
LB2
LB1 = light bulb #1LB2 = light bulb #2PB1 = push button #1MR1= Motor contacts #1M1 = Meter #1M2 = Meter #2
Circuit ladder Diagram
0
voltage
+
NO
0
Current
+
0
current
NO
relayCartoon of circuit
Ladder diagram of circuit
0
voltage
PB 1
PB 1
LB 1
LB 1
MR 1
MR 1
M1
M1
LB1 = light bulb #1LB2 = light bulb #2PB1 = push button #1MR1= Motor contacts #1M1 = Meter #1M2 = Meter #2
+
0
voltmeter
NO
NO0
currentmeter
NO
Relay with N.O. auxiliary contacts
+
Relay with N.O. auxiliary contacts
0
voltmeter
NO
0
currentmeter
NO NO
+
Relay with N.O. auxiliary contacts
0
voltmeter
NO
0
currentmeter
NO NO
This relay circuit is now energized.
This relay circuit is now energized.
+
0
voltmeter
NO
NO0
currentmeter
NO
Relay with N.O. auxiliary contacts
This relay circuit is de-energized.
This relay circuit is de-energized.
Relay with N.O. auxiliary contacts
Cartoon of circuit
Ladder diagram of circuit
NONO
+
0
voltage
NO
0
current
0
voltage
PB 1LB 1 MR 1 M1
PB 1
LB 1
MR 1
M1
Relay with N.O. auxiliary contacts
Cartoon of circuit
Ladder diagram of circuit
NONO
+
0
voltage
NO
0
current
0
voltage
PB 1LB 1 MR 1 M1
PB 1
LB 1
MR 1
M1
CR 1
LB2CR 1
LB2
Relay with N.O. auxiliary contacts
Cartoon of circuit
Ladder diagram of circuit
NONO
+
0
voltage
NO
0
current
0
voltage
PB 1LB 1 MR 1 M1
PB 1
LB 1
MR 1
M1
CR 1
LB2CR 1
LB2
Motor circuit is energized.
Relay with N.O. auxiliary contacts
Cartoon of circuit
Ladder diagram of circuit
NONO
+
0
voltage
NO
0
current
0
voltage
PB 1LB 1 MR 1 M1
PB 1
LB 1
MR 1
M1
CR 1
LB2CR 1
LB2
Motor circuit stays energized.
Relay with N.O. auxiliary contacts
Cartoon of circuit
Ladder diagram of circuit
NONO
+
0
voltage
NO
0
current
0
voltage
PB 1LB 1 MR 1 M1
PB 1
LB 1
MR 1
M1
CR 1
CR 1
Relay with N.O. auxiliary contacts
Cartoon of circuit
Ladder diagram of circuit
NONO
+
0
voltage
NO
0
current
0
voltage
PB 1LB 1 MR 1 M1
PB 1
LB 1
MR 1
M1
CR 1
CR 1
Motor circuit is energized.
Relay with N.O. auxiliary contacts
Cartoon of circuit
Ladder diagram of circuit
NONO
+
0
voltage
NO
0
current
0
voltage
PB 1LB 1 MR 1 M1
PB 1
LB 1
MR 1
M1
CR 1
Motor circuit stays energized.
Push button is disengaged.
Ladder diagram still shows a continuous path from the left to right through the relay. The motor
relay circuit has been “sealed in”.
CR 1
0
voltmeter
+
NO
NONC0
currentmeter
Relay with N.C. auxiliary contacts
This relay circuit is now de-energized.
This relay circuit is now energized.
0
voltmeter
+
NO
This relay circuit is now energized.
This relay circuit is now de-energized.
0
currentmeter
NONC
Relay with N.C. auxiliary contacts
This relay circuit is now de-energized.
This relay circuit is now energized.
0
voltmeter
+
NO
0
currentmeter
NONC
Relay with N.C. auxiliary contacts
0
voltage
+
NO
0
current
NC
Relay with N.C. auxiliary contacts
Cartoon of circuit
Ladder diagram of circuit
0
voltage
PB 1LB 1 MR 1 M1
CR 1
PB 1
LB 1
MR 1CR 1
NO
0
voltage
+
NO
NO0
current
NC
Relay with N.C. auxiliary contacts
Cartoon of circuit
Ladder diagram of circuit
0
voltage
PB 1LB 1 MR 1 M1
CR 1
PB 1
LB 1
MR 1CR 1
However, since the coil is energized, the CR 1 contacts are forced out of their normal position. They immediately open and cause an open circuit that de-energizes the coil.
0
voltage
+
NO
NO0
current
NC
Relay with N.C. auxiliary contacts
Cartoon of circuit
Ladder diagram of circuit
0
voltage
PB 1LB 1 MR 1 M1
CR 1
PB 1
LB 1
MR 1CR 1
Now the CR1 contacts return to their normal position, the coil is re-energized and then the CR 1 contacts are again forced out of their normal position.
0
voltage
+
NO
NO0
current
NC
Relay with N.C. auxiliary contacts
Cartoon of circuit
Ladder diagram of circuit
0
voltage
PB 1LB 1 MR 1 M1
CR 1
PB 1
LB 1
MR 1CR 1
This oscillation of the CR1 and MR 1 contacts continues as long as PB 1 is passive.
0
voltage
+
NO
NO0
current
NC
Relay with N.C. auxiliary contacts
Cartoon of circuit
Ladder diagram of circuit
0
voltage
PB 1LB 1 MR 1 M1
CR 1
PB 1
LB 1
MR 1CR 1
This immediately causes the CR 1 contacts to return to their normal position and re-energize the coil. This cycling (oscillation) continues until the CR 1 contacts burn out.
0
voltage
+
NO
NO0
current
NC
Relay with N.C. auxiliary contacts
Cartoon of circuit
Ladder diagram of circuit
0
voltage
PB 1LB 1 MR 1 M1
CR 1
PB 1
LB 1
MR 1CR 1
The same oscillation behavior will happen in this circuit arrangement when PB 1 is or is not engaged.
Pre-presentation Self Assessment Activity
2) The following diagram indicates that the relay circuit controlled by MR1 is energized after the pushbutton has been pushed and then released.
yes
no
PB 1LB 1 MR 1 M1
CR 1
1) Draw a ladder circuit diagram that will show the wiring of a normally open push button such that pushing the button will seal in a motor relay contact set, MR1.
PB 1LB 1 MR 1 M1
CR 1
x
End of Presentation