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2012 Hands On Relay School Print Reading
Jeff Marsh
Basics One Line Schematics Three Line (CT‐PT) Schematics Electro‐Mechanical Breaker Example Electro‐Mechanical Sequencer Example Wiring Prints ANSI vs. IEC Miscellaneous Prints
Basics
Form A or N.O. or SPST
Form B or N.C. or SPST
Form C or SPDT Contacts are typically shown in their de‐energized or relaxed state. TON or TDPU A timer that has a delay on energization but no delay on de‐enerization. TOFF or TDDO A timer that has a delay on de‐energization but no delay on enerization. 52a Follows the state the breaker main contacts
52b Inverse of the state the breaker main contacts
POS Fire Detector 1
Fire Detector 2
125 VDC
94F‐X NEG HOT
POS
Start
Contactor
94F‐X Stop
120 VAC
24 VDC
Fan Motor Contactor 94F‐X
PLC Input
OL NEG
NEUT
POS Fire Detector 1
Fire Detector 2
125 VDC
62F‐X TDPU 5” NEG HOT
POS
Start
Contactor
62F‐X Stop
120 VAC
24 VDC
Fan Motor Contactor 62F‐X
PLC Input
OL NEG
NEUT
POS
Fire Detector 1 Fire Detector 2
125 VDC
94F‐X NEG HOT
POS
Start
Contactor
94F‐X Stop
120 VAC
24 VDC
Fan Motor Contactor 94F‐X
PLC Input
OL NEG
NEUT
POS
Fire Detector 1 Fire Detector 2
125 VDC
62F‐X TDDO 5” NEG HOT
POS
Start
Contactor
62F‐X Stop
120 VAC
24 VDC
Fan Motor Contactor 62F‐X
PLC Input
OL NEG
NEUT
One Line Schematics
Three Line (CT‐PT) Schematics
Electro‐Mechanical Breaker Example
Electro‐Mechanical Sequencer Example
Wiring Prints
ANSI vs. IEC
Adobe Acrobat Document
Miscellaneous Prints
Closes at 64 psi Falling at 20 Degrees C