Teknic EF-785, Installation Manual

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E
XTENDING THE
S
YSTEM
C
ONTROLLING
E
XTERNAL
H
AZARDOUS
E
NERGY
The eF-785 may also be used to control and monitor an alternate power
supply or a redundant disconnect. Circuits are provided at P13 to control
the flow of external hazardous energy along with circuits for monitoring
the disconnect of that energy in compliance with EN 954-1.
In order to comply with EN 954-1, a redundant means of
disconnecting power must be used with a high reliability means of
verifying that hazardous power has been removed
4
. In this context,
“hazardous power” can be electrical, hydraulic, pneumatic, chemical, etc.
The most common example of this application is the use of 3-phase AC
power (see diagram below).
E
XAMPLE
: 3-P
HASE
P
OWER
C
ONTROL
In this example, 3-phase AC power is switched along with other Main
area power. In order for the eF-785 to be able to control and monitor the
switching of 3-phase AC power, an external 3-phase contactor must be
used. This contactor must be of the type that has three normally open
contacts for switching power as well as one normally closed contact that
monitors the state of the power contacts. The NC contact must be
guaranteed to be open if any of the NO contacts weld closed (per EN
60947-5-1 Annex L). These contacts provide feedback to the eF-785 that
the hazardous power has been removed from the connected 3-phase
load(s). These feedback contacts must be positively-guided per EN
50205. This means that the feedback contacts must remain open if any
power contact welds closed, even after power is removed from the
contactor’s coil.
+
P2
eF-785
30A, 3-phase
disconnect
30A, 3-phase
ckt. breaker
1
3
18
15
17
6
3-phase
AC power
source
BRN
BLK
GRY
Katko/KU 340N Airpax/209-3-1-
64-4-8-30-HV
External
30A contactor
Sp Schuh/
CA7-30C-01-24D
To 3-phase
loads
AC Input
P13 Safety
Control
Extension
3-Phase Power Control
4 Assumes that the 3-phase power is used in a machine that is consistent with the
assumptions discussed in Appendix A.
e F - 7 8 5 I
N S T A L L A T I O N
M
A N U A L
57
T
EKNIC
, I
NC
F
AX
(585)784-7460 V
OICE
(585)784-7454