Chapter 4 Installation and Wiring
4-91
2. Transistor output
Load through
which the direct
current flows
DC power supply
ZP
Y0.0
UP
+
NPN transistor output (sinking)
Load through
which the direct
current flows
ZP
Y0.0
UP
+
DC power supply
PNP transitor output (sourcing)
3. TRIAC output
Load through which the
alternating current flows
Relay Output Circuit
Relay terminals have no polarity. They can be applied to alternating current which passes through a load, or direct current
which passes through a load. The maximum current which can passes through every relay terminal is 2 A, and the
maximum current which can passes through every common terminal is 5 A. The lifetime of a relay terminal varies with the
working voltage, the load type (the power factor cosψ), and the current passing through the terminal. The relation is
shown in the life cycle curve below.
Contact Current(A)
20
0.5
0.1
0.2
30
50
0.3 0.7
1 2
200
300
500
100
1000
2000
3000
Operation(X10 )
3
120VAC Resistive
30VDC Inductive(t=7ms)
240VAC Inductive(cos 0.4)
ψ
=
120VAC Inductive(cos =0.4)
ψ
30VDC
Inductive
(t=40ms)