G3H203SNDC524 Datasheet, PDF (6/12 Pages) Omron Electronics LLC – Solid State Relays Technical Information

Heater Load (Resistive Load)
A resistive load has no inrush current. The SSR is generally used
together with a voltage-output temperature controller for heater ON/
OFF switching. When using an SSR with the zero cross function,
most generated noise is suppressed. This type of load does not,
however, include all-metal and ceramic heaters. Since the resistance
values at normal temperatures of all-metal and ceramic heaters are
low, an overcurrent will occur in the SSR, causing damage. For
switching of all-metal and ceramic heaters, select a Power Controller
(G3PX, consult your OMRON representative) with a long soft-start
time, or a constant-current switch.
Temperature
Controller
(voltage output)
Heater load
Lamp Load
A large inrush current flows through incandescent lamps, halogen
lamps, and similar devices (approx. 10 to 15 times higher than the
rated current). Select an SSR so that the peak value of inrush current
does not exceed half the inrush current resistance of the SSR. Refer
to “Repetitive” (indicated by the dashed line) shown in the following
figure. When a repetitive inrush current of greater than half the inrush
current resistance is applied, the output element of the SSR may be
damaged.
Half-wave Rectifying Circuit
AC electromagnetic counters and solenoids have built-in diodes,
which act as half-wave rectifiers. For these types of loads, a half-
wave AC voltage does not reach the SSR output. For SSRs with the
zero cross function, this can cause them not to turn ON. Two meth-
ods for counteracting this problem are described below.
• Connect a bleeder resistance with approximately 20% of the
SSR load current.
Bleeder resistance
Load
• Use SSRs without the zero cross function.
Full-wave Rectified Loads
AC electromagnetic counters and solenoids have built-in diodes,
which act as full-wave rectifiers. The load current for these types of
loads has a rectangular wave pattern, as shown in the following dia-
gram.
Non-repetitive
Load
Repetitive
Circuit current
wave pattern
Energized time (ms)
Motor Load
When a motor is started, an inrush current of 5 to 10 times the rated
current flows and the inrush current flows for a longer time than for a
lamp or transformer. In addition to measuring the startup time of the
motor or the inrush current during use, ensure that the peak value of
the inrush current is less than half the inrush current resistance when
selecting an SSR. The SSR may be damaged by counter-electromo-
tive force from the motor. Be sure to install overcurrent protection for
when the SSR is turned OFF.
Transformer Load
When the SSR is switched ON, an energizing current of 10 to 20
times the rated current flows through the SSR for 10 to 500 ms. If
there is no load in the secondary circuit, the energizing current will
reach the maximum value. Select an SSR so that the energizing cur-
rent does not exceed half the inrush current resistance of the SSR.
Accordingly, AC SSRs use a triac (which turns OFF the element only
when the circuit current is 0 A) in the output element. If the load cur-
rent waveform is rectangular, it will result in an SSR reset error.
When switching ON and OFF a load whose waves are all rectified,
use a -V model or Power MOS FET Relay.
-V-model SSRs:
G3F-203SL-V, G3H-203SL-V
Power MOS FET Relay: G3DZ, G3RZ, G3FM
Solid State Relays Technical Information
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