Brochure

ESG
8.668.66
8.668.66
8.66
Phase control. Turn-on of a nonzero switching SSR
(each half cycle), at a phase angle determined by the
control signal source.
Power dissipation. The maximum average power
dissipation [watts] resulting from the effective voltage
drop (power loss) in the SSR output semiconductor.
RMS Voltage (Root-Mean-Square). The value of
alternating voltage (ac) that would produce the same
power dissipation as continuous voltage (dc) in a resisti-
ve load. For a sine wave, RMS is 0,707 times the peak
value.
Semiconductor fuse. A specially constructed fast-
acting fuse capable of protecting semiconductor de-
vices, with opening times typically less than 10 millise-
conds.
Snubber. A resistor-capacitor combination placed
across the SSR output terminals to control dv/dt and
transients in thyristor circuits.
Solid-State-Relay, SSR. Isolated On-Off-Switch
composed of non-moving electrical parts (i.e., primarily
semiconductors, transformer and passive components).
Surge current. The maximum allowawble SSR mo-
mentary current flow for a specific time duration. (Typi-
cally specified as a peak value for one line cycle for ac).
Thermal resistance (R
θθ
θθ
θ). Expressed in "degrees
celsius per watt" [°C/W]. This value defines the tempera-
ture gradient in the path between the power generated
in the ouptut SSR semiconductor and the final dissipa-
ting medium (heat sink/air).
Thyristor. A semiconductor bistable device comprising
three or more junctions (PNPN, etc.). The generic name
for a family of gate controlled switches including SCRs
and triacs.
Transient. Brief overvoltage or overcurrent excursion
from normal condition.
Transient overvoltage. The maximum allowable
brief excursion of applied voltage that an SSR can
withstand without damage or malfunction while maintai-
ning its off state.
Transistor. Generally a three-terminal semiconductor
device with dc current flow between two terminals
modulated by the third. A bipolar transistor is essentially
a current-controlled device, while a field-effect transistor
is a voltage-controlled device.
Triac. Bidirectional semiconductor of the thyristor
family. Performance is similar to that of an inverse pair of
SCRs, triggered by a single gate electrode.
Turn-off time (Maximum). The maximum time
between the removal of the turn-on control signal and
the transition of the output device to its blocking (off)
state.
Turn-off voltage. The voltage applied to the input at
or below which the output is guaranteed to be in the off
state.
Turn-on time (Maximum). The time between the
application of a turn-on control signal and the transition
of the SSR output to its fully conducting state.
Turn-on voltage (Must Operate). The voltage
applied to the SSR input at or above which the output
must be in the on state (normally open).
Varistor. See Metall Oxid Varistor (MOV).
Zero Voltage Turn-On. The maximum (peak) off
state voltage that appears across the SSR output termi-
nals immediately prior to initial turn-on, following a turn-
on control signal.