Grounded Ac Power-Distribution System With Master-Control Relay - Allen-Bradley SLC 500 Installation And Operation Manual

Incoming
AC
The I/O circuits form a net
inductive load switched by the
CRM contacts. Therefore, a
suppressor is needed
across the line at the load
side of the CRM contacts.
To minimize EMI generation, connect a suppressor across an inductive load. For more information on selecting surge suppressors, see page 2–24.
Contact motor manufacturer for recommended surge supression for motors.
In applications where severe energy is re-generated by motors when power is removed, use an isolation/constant-voltage transformer in place of the step-down
transformer.
In many applications, a second transformer provides power to the input circuits and power supplies for isolation from the output circuits.
Connect a suppressor here to minimize EMI generation from the net inductive load switched by the CRM contacts. For more information on selecting surge
suppressors, see page 2–24.
!

Grounded ac Power-Distribution System with Master-Control Relay

Disc.
Suppressor
1FU
L1
2FU
L2
3FU
L3
H
1
H
3
FUSE
X
1
Multiple E-stop switches
Start
CRM
Controller
Power Supply
L1
CRM
Suppressor
Input
Module
Wiring
Output Module
Arm
Wiring Arm
Input
Sensor
System Installation Recommendations
ATTENTION: Your SLC 500 power supply can be
damaged by voltage surges when switching inductive
loads such as motors, motor starters, solenoids, and
relays. To avoid damage to your SLC 500 power
supply in these applications, it is strongly
recommended that an isolation transformer be used to
isolate the power supply from harmful voltage surges.
L1
To Motor
L2
Starters
L3
H
4
H
2
Step-down
Transformer
Grounded Conductor
X
2
CRM
1
Suppressor
GND
N or L2
Output
Actuator
CRM
Enclosure
Wall
Back-panel
Ground Bus
Grounding-electrode
Conductor to
Grounding-electrode
Equipment-
System
Grounding
Conductors
Connect
when applicable
User DC
Supply
To DC I/O
actuators/
sensors
Publication 1747-6.2
3–9