Rockwell Automation 1503FC IntelliVAC Contactor Control Module - Series E - Manual (Page 25)

3-12 Installation and Wiring
1503-UM053B-EN-P – June 2013
Control with Solid-State Devices
When control devices that employ electronic or suppressed output
circuits are used in the rung(s) that control the inputs to the IntelliVAC,
alternate arrangements may be required. Devices employing transistor or
triac output circuits have finite impedance and allow a leakage current to
flow in the blocking or off state. Some PLC and I/O modules with relay
outputs have R-C snubber circuits across the contact to suppress voltage
transients generated during contact opening. The impedance of these
snubber circuits also allows leakage current to flow when the contacts are
open. The IntelliVAC input circuits have been designed such that typical
output leakage currents should not create unintended operation of the
contactor. The vast majority of control devices may be directly connected
to the IntelliVAC without any inappropriate operation occurring.
This situation can be prevented by consideration of the control devices
when designing the control system. With control devices that have
excessive leakage current (i.e. PLC or similar control devices) consider
using relay outputs with now suppression across the contacts. If this
cannot be done, consider the leakage current of the device to see if it is
compatible with the IntelliVAC inputs (see Table 1.A). If the control
device is not compatible consider using an interposing relay connected as
shown in Figure 3.6.
- +
3
2
12
11
AUX
MOV
M
TCO
5
6
-
+
1
EC
CCO
4
9 10
M
CLOSE
N
G
OVERLOAD
*
CONTROL
POWER
FUSE
CONTROL POWER
M
M -IV
M -IV
L
CR
CR
SOLID STATE
OUTPUT
INPUT POWER
* Refer to Table 3.A for recommended fuse sizing.
Figure 3.6 – Control with Solid-State Devices