Brochure

ESG
8.588.58
8.588.58
8.58
The diagrams in this section are conceptual illustrations
of just a few typical SSR applications. They are intended
as design guides to steer the user in the right direction
and to stimulate further design ideas. Some of the
diagrams provide problem solving or circuit protection
and others enhance relay operation.
Latching SSR
(Fig. 13) (Fig. 13)
(Fig. 13) (Fig. 13)
(Fig. 13)
Momentary push-button control allows the SSR to self-
latch for on-off, stop-start operations. It may be similarly
configured for DC in/DC out type SSRs.
Resistor R1 (10 kΩ) is required to prevent line short only
if alternate (NO = normaly open) switch is used.
Latching SSR with short-circuit protection
(Fig. 14) (Fig. 14)
(Fig. 14) (Fig. 14)
(Fig. 14)
Push-button control as in the previous example, but R2
is tailored to limit the load shorting current to SSR
surge rating (for turn-off time), thus preserving SSR
while the control signal is removed. Latching characte-
ristic permits lock-out until the circuit is reset.
SSR Applications
Motor starter switch
(Fig. 15) (Fig. 15)
(Fig. 15) (Fig. 15)
(Fig. 15)
Initial locked rotor current flowing through R1 creates a voltage that, when rectified and filtered, turns on the SSR,
which in turn activates the start winding. As the motor comes to speed, the voltage across R1 is reduced until the
start winding is de-energized.
The SSR should have a voltage rating approximately twice that of the applied line to withstand overvoltage
generated by the current LC.
AC
output
SSR
AC
input
AC Power
(120 - 240 V)
N O
Start-
Reset
R
2
10 kΩ
N C Stop
R
L
Fig. 14: Latching SSR with short-circuit protection
AC
output
SSR
AC
input
AC power
(120 - 240 V)
N O
Start
R
1
10 kΩ
N C
Stop
N O Stop
(Alternate)
R
L
Fig. 13: Latching SSR circuit
AC Power
AC
output
SSR
DC
input
Motor
R
2
R
1
FWB
C
1
C
2
R
3
Start winding
Run winding
+
–
Fig. 15: Motor starter switch