Watlow Series 942 - Manual (Page 16)

Install and Wire, Chapter 2
16 WATLOW Series 942 User's Manual
Output 2 Wiring
Solid State Relay Without Contact Suppression
Watlow's solid state relays change state at zero volts, which is "zero-cross switching." They
are also optically isolated, which means the output circuitry is energized by infrared light
striking a photosensitive device. This results in virtual absence of electrically generated
noise, while providing output to input electrical isolation. Off state impedance is nearly
infinite and should be used to switch high impedance non-inductive loads.
Mechanical Relay
The electromechanical relay is an electrical and mechanical device with moving parts.
When power is applied to the relay solenoid, contact closure is created through movement
of the "common" contact of the relay. Off state impedance is 20K
Ω
minimum.
Mechanical Relay, 6 Amp, Form A, Output 2
Model # 942A - _ _ D _ - _ 000
Mechanical Relay, Form A, 6 Amp
15
14 N.O.
COM.
Fuse
L1
L2
External
Load
L2
L1
Figure 22 -
6 Amp Mechanical
Relay, Output 2
Wiring.
Figure 23 -
Solid State Relay
Without Contact
Suppression,
Output 2 Wiring.
NOTE:
This output is sup-
plied with an arc
suppression snub-
ber across the out-
put terminals. High
impedance loads
may remain ener-
gized even though
the output device is
turned OFF.
Solid State Relay Without Contact Suppression, Output 2
Model # 942A - _ _ K _ - _ 000
COM.
N.O.
External
Load
Fuse
L1
L2
15
14
Solid State Relay, Form A, 0.5 Amp
L1
L2