5 Application examples
EMS2… Electronic motor starter 10/19 MN034003EN www.eaton.com 33
5 Application examples
One of the reasons why EMS2 electronic motor starters achieve such a high
lifespan is that the power to the contacts that are located in the device can
be disconnected. This is done by the triggering of semiconductors and relays
by the internal electronics. For this function to be active, the motor starter
needs to constantly be supplied with control voltage to terminals A1 and A2.
There are, however, application cases (for example, when the actuation is
carried out via a PLC) in which the supply voltage on the terminals A1 and A2
is turned off in order to achieve a safe state after a controlled stop.
CAUTION
Since the control supply voltage or the control voltage of the
hybrid motor starter is disconnected via a single channel, this
type of installation according to SIL 3 (Cat. 3, Cat. 4) is permit-
ted, only if error prevention for cross circuits according to
EN ISO 13849 is permitted.
This is the case, for example, if the hybrid motor starter and the
safety relay are installed in the same switch cabinet.
If such error prevention is not permitted, the control supply volt-
age must be disconnected via two channels or two positions
(￫ section 5.1, “Single-channel controlled stop application
(cat. 3, SIL 3, PL e) with error prevention”, page 34,
￫ section 5.2, “Reversing starter 24 V DC with safety function
(dual-channel) (cat. 3, SIL 3, PL e)”, page 36).
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