700-SH Datasheet, PDF (7/7 Pages) Allen-Bradley – Solid-State Relays

Bulletin 700-SH
Solid-State Relays
Basic Application Considerations
Load Connection
• For an AC load, use a power supply rated at 50 or 60 Hz. The maximum operating frequency is 10 Hz.
• The Bulletin 700-SH has a built-in varistor for surge/inrush protection of AC loads. If additional suppression is required, connect an external
varistor across the load device terminals. Select a varistor which meets the load voltage condition outlined in the table below.
Load Voltage
100…120V AC
200…240V AC
380…480V AC
Varistor Voltage
240…270 V
440…470V
820…1000V
Varistor Surge Resistance
1000 A min.
Zero Cross Function
A SSR with a zero cross function operates when an AC load voltage reaches the zero point or its vicinity. This reduces clicking noises when the load is
switched, and minimizes the influence of an inductive load, such as a lamp, heater, or motor, on the power supply because the inrush current of the load is
reduced. This can also minimize the scale of the inrush current protection circuit.
Output (load voltage)
Input
ON
OFF
At a low applied voltage, such as 24V AC, the load current is not fully supplied. When the unit is switched ON, the voltage required to power the unit deprives
the output signal of the necessary voltage level and thus creates loss time. The lower the load voltage is, the greater the loss time is. This condition, however,
will not create any serious problems.
Loss time
For a DC inductive load, a diode should be connected parallel to the load to absorb the counter electromotive force (OFF) of the load.
Input
SSR
Load
Load power
supply
Note: For additional details when using Solid-State Relays, refer to pub. 700-AT001A--EN-E, “Solid-State Relay Application Guide" available at
www.theautomationbookstore.com.
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