Bypass Circuit For Emergency Operation - Eaton DS7 Manual

7.3.7 Bypass circuit for emergency operation

￫
Devices of the DS7-34... series are equipped with integrated
bypass contacts. External bypass contacts are therefore not
required for standard operation.
In pump applications the bypass circuit is often required to provide emergency
operation capability. A service switch (key switch) is used to select the bypass
circuit between soft starter operation and DOL starter operation. This is used to
fully isolate the soft starter.
In this case, it is important that the output circuit is not opened during operation.
The interlocks in the controller ensure that a switchover is only possible after a
stop.
￫
Unlike the simple bypass operation, in this case the bypass
contactor must be designed in accordance with utilization
category AC-3. For a suitable contactor, see our recommended
mains contactor in the Appendix (￫ page 221).
L01/L+
K1
S1
S2 Q22
K1 K3
K2
S3 K1
K4
Q21
EN
K1 K2
A2
L00/L-
a
Figure 109: Actuation with bypass emergency operation – pump operation
a Enable
b Automatic operation (soft starter)
c Manual/bypass operation
d Soft starter/Soft stop
e Bypass contactor
The electrical and/or mechanical interlocking of contactors Q22 and Q31 ensures
safe operating states.
DS7 Soft starter 09/16 MN03901001Z-EN www.eaton.com
S4
K2 K3 K4 S5
Q31
K3 Q31 Q11 K5
b c
S1 = Operating mode selector switches
S2 = Off
S3 = On
S4 = Stop (Soft starter)
S5 = Start (Soft starter)
7 Connection examples
7.3 Size 3 and 4 (41 – 200 A)
Q21
23
K5 K5 RUN TOR
24
Q21
A1
K4 Q22
A2
d
13
K2
14
e
139