ABB Jokab Safety JSBR4 Series Safety Relays – A GalcoTV Overview

ABB Jokab Safety JSBR4 Series Safety Relays – A GalcoTV Overview


Welcome to G-TV! Today, I will be showing
you ABB’s Jokab Safety JSBR4 Safety Relays. The JSBR4 Safety Relay is a universal relay
for two handed devices. The JSBR4 has two inputs, which both have to be closed to keep
the safety output contacts closed. A short circuit across the inputs will cause the output
contacts to open. The inputs can however be subjected to a continuous short circuit without
damaging the safety relay. To make the safety outputs closed, the reset input must be closed
and opened. In this way an unintentional reset is prevented in the case of a short circuit
in the reset button cable or if the button gets jammed in the actuated position. The
reset can also be used for test or supervision to ensure that contactors or valves have returned
to their initial stop position before a new start can be allowed by the safety relay.
When the JSBR4 is used as a two hand relay both buttons have to be pressed within 0.5
seconds of each other in order to close the outputs. When the safety relay is used for
safety mats and safety strips, the stop condition is given, following detection of short circuit
between input channels A and B. Neither the safety mat nor the relay will be damaged by
a continuous short circuit. This also gives the advantage that if there is a failure between
inputs in the installation, the safety relay will not be damaged. ABB’s Jokab Safety
JSBR4 Safety Relays, along with thousands of other products and services, are available
at galco.com.

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