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3RT1/3RH1 contactors
SIRIUS System Manual
GWA 4NEB 430 0999-02b
3-75
Diode
Figure 3-58: Circuit with a diode (AC/DC operation)
This is what happens when a coil is disconnected that is connected to a
diode:
Advantages: No overvoltage occurs during disconnection. The diode block
becomes effective at 0.6 V.
Disadvantage: The diode can only be used for DC operation.
The break time of the contactor is considerably increased and amounts to 6
to 9 times the off-delay.
This increased break time can be used, if necessary, for control purposes,
such as for bridging brief interruptions in voltage.
Zener diodes (diode combinations) are available for shorter break times. The
break time then amounts to 2 to 6 times the off-delay.
Surge suppressors
The following surge suppressors are available for the 3RT1 contactors:
Table 3-28: Surge suppressor
Circuit with diode
(DC operation)
0
200
20
U
Sp
[V ]
0
t
[
µ
s]
U
Sp
= 0,6 V =
U
SP
der D iode
^
Surge suppressor
With LED
Without
LED
For S00
For S00
For S0
For S2, S3
Suppression diode
x
x
--
--
Diode combination:
suppression diode and Zener
diode
--
x
x
x
Varistor
x
x
x
x
RC element
--
x
x
x