Brochure/Catalogue

for EMR for SSR
Surge voltage category The overvoltage category of a circuit or an electrical system is numbered
conventionally (from I to IV) and is based on limiting the assumed surge voltage
values that can occur in a circuit (or electrical system with different mains
voltages). The assignment to a particular overvoltage category is dependent on
the measures which are used to inuence (reduce) the surge voltages.
Overvoltage category I
• Devices that are intended to be connected to the permanent electrical building
installation.
The measures for limiting transient surge voltages to the proper level are taken
outside of the device. The protective mechanisms can either be in the permanent
installation or between the permanent installation and the device.
Overvoltage category II
• Devices that are intended to be connected to the permanent electrical building
installation (such as a household appliances or portable tools).
Overvoltage category III
• Devices that are a part of the permanent installation and other devices where
a higher degree of availability is required. This includes the distributor panels,
power switches, distribution systems (including cable, busbars, distributor
boxes, switches and outlets) that are part of the permanent installation,
devices intended for industrial use, and devices that are continually connected
to the permanent installation (such as stationary motors).
Overvoltage category IV
• Devices that are intended to be used on or near the power feed in a building‘s
electrical installation – ranging from the main distribution to the mains power
system. This includes electrical meters, surge protection switches and ripple
control equipment.
x x
Switch-off delay Typical time interval from switching off the rated control voltage of a switched
electromechanical relay and solid-state relay until the rst opening or closing of
the last output circuit (not including the bounce time).
For AC, specications are valid for 50 Hz unless otherwise indicated.
Measured at room temperature (approx. 23 °C) and an only briey energised
input (coil temperature below thermal stability).
The switching times are strongly dependent on environmental parameters such
as ambient temperature, mounting position, manufacturing tolerances, voltage
level of the control signal and the shape of the control signal. Therefore, the
values in the application may differ from the data sheet specications.
x x
Switch-on delay Typical time interval from switching on the rated control voltage of an
electromechanical relay and solid-state relay until the rst closing or opening of
the last output circuit (not including the bounce time).
For AC, specications are valid for 50 Hz unless otherwise indicated.
Measured at room temperature (approx. 23 °C) and coil temperature equal to
room temperature.
The switching times are strongly dependent on environmental parameters such
as ambient temperature, mounting position, manufacturing tolerances, voltage
level of the control signal and the shape of the control signal. Therefore, the
values in the application may differ from the data sheet specications.
x x
EMR = Electromechanical relay
SSR = Solid-state relay
W
Technical appendix/Glossary
W.38 2737920000
Glossary: Relay modules and Solid-state relays