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5
Model 581A Differential Pressure Switch
Section 1
100
0
50
Zero DP
100
0
50
Maximum DP
D
E
R
Y
OL
L
E
W
B
UL
E
B
C
AL
K
N
E
E
R
G
W
H
IT
E
100
0
50
SWITCH "A"
(LEFT)
SWITCH "B"
(RIGHT)
CAM
TERMINAL
BLO CK IN
CAS E
BOTH SWITCHES RELAX ED
SWITCH
PLUNGER
SCREW
Mid-point DP
HIGH
LOW
SWITCH "A" AC TUAT ED/SWITCH "B" RELAX ED
SWITCH "A" RELAX ED/SWITCH "B" AC TUAT ED
SWITCH
CLOSED
CONTACTS
OPEN
CONTACTS
GREEN/WHITE GREEN/BLACK
A (LEFT)
B (RIGHT)
YELLOW/BLUE
YELLOW/RED
SWITCH
CLOSED
CONTACTS
OPEN
CONTACTS
GREEN/WHITE GREEN/BLACK
A (LEFT)
B (RIGHT)
YELLOW/RED
YELLOW/BLUE
SWITCH
CLOSED
CONTACTS
OPEN
CONTACTS
GREEN/WHITE
GREEN/BLACK
A (LEFT)
B (RIGHT)
YELLOW/BLUE
YELLOW/RED
SWITCH "A"
(LEFT)
SWITCH "B"
(RIGHT)
SWITCH "A"
(LEFT)
SWITCH "B"
(RIGHT)
Notes:
1. CAM ROTATES COUNTER-CLOCKWISE WITH INCREASED DIFFERENTIAL PRESSURE
2. EACH SWITCH MAY BE SET AT ANY POINT FROM 10% TO 90% OF DP RANGE
3. WIRES: No. 22 AWG (Internal) and No. 18 AWG (External)
Figure 1.3—Switch wiring connections and actuation example
Wiring
Each switch is wired internally to a glass-sealed header using No. 22 AWG
®
) insulated wire for radiation service per
IEEE Standard 393-1974. Externally, from the header, permanently color
coded No. 18 AWG Tefzel
®
wires exit through a female conduit connection.
Differential Pressure Unit
For detailed information on the Model 199 DPU, see Appendix A.