Rockwell Automation SMC-Flex, User Manual

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Product Overview 1-11
Protection and Diagnostics
The SMC-Flex controller provides the protective and diagnostic
features described below.
Overload
The SMC-Flex controller meets applicable requirements as a motor
overload protective device. Thermal memory provides added
protection and is maintained even when control power is removed.
The built-in overload controls the value stored in Parameter 12, Motor
Thermal Usage; an Overload Fault will occur when this value reaches
100%. The programming parameters below provide application
flexibility and easy setup.
Notes: (1) The factory default setting for Overload Class, which is
10, enables overload protection. The motor’s full load
current rating must be programmed to properly set
overload protection.
(2) Automatic reset of an overload fault requires the start
input to be cycled in a 2-wire control scheme.
The trip rating is 117% of the programmed FLC.
Figure 1.13 and Figure 1.14 provide the overload trip curves for the
available trip classes.
Underload
➀
Utilizing the underload protection of the SMC-Flex controller, motor
operation can be halted if a sudden drop in current is sensed.
The SMC-Flex controller provides an adjustable underload trip
setting from 0…99% of the programmed motor full load current
rating. Trip delay time can be adjusted from 0…99 seconds.
➀
Underload protection is disabled during slow speed and braking operations.
Parameter Range
Overload Class Off, 10, 15, 20, 30
Overload Reset Manual – Auto
Motor FLC
1.0
…
2200 A
Service Factor
0.01
…
1.99