Rockwell Automation 1333 Drive, 3/4-5HP, 230-575V Series D - Manual (Page 55)

Operation and Programming
Chapter 5
5-12
Overload Protection Settings
Important: Parameters 6 and 7 are intended for use on single motor
applications. For multiple motor applications, Parameter 6 must be set to 0
to help avoid nuisance tripping.
Parameter 06 -- Motor Duty
Units = Code
Range = 0/1/2/3
Factory Setting = 2
Parameter 6 provides three thermal overload functions. When used in
conjunction with Parameter 7, a thermal overload function that matches the
motor nameplate amps can be used.
If set to 0, the overload function will not include thermal protection and the
drive will trip at its standard setting of 140% of rated drive output current
after 60 seconds. If set to 1, 2 or 3, the thermal overload function is
enabled and will function as described below.
If set to 1, the drive will trip at 115% of the current set in Parameter 7, or
140% of rated drive output current (whichever is lower) after 60 seconds.
When set to 1, the thermal overload trip point is constant across the entire
speed range of the motor. This performance is typical with A-B Bulletin
1329 10:1 speed range motors.
If set to 2, the drive will trip at 115% of the current set in Parameter 7, or
140% of rated drive output current (whichever is lower) after 60 seconds.
When set to 2, the thermal overload curve generated is derated below
50 Hz for use with motors having a 4:1 speed range. This performance is
typical with A-B Bulletin 1329 4:1 speed range motors.
If set to 3, the drive will trip at 115% of the current set in Parameter 7, or
140% of rated drive output current (whichever is lower) after 60 seconds.
When set to 3, the thermal overload curve generated is derated below
15 Hz for use with motors having a 4:1 speed range. This performance is
typical with A-B Bulletin 1329 4:1 speed range motors.
Important: The National Electrical Code requires that motor overload
protection be provided in the motor branch circuit. Parameter 6 when used
with Parameter 7 provides motor overload protection. NEC however,
recognizes this protection as being provided by eutectic alloy or bi-metal
overload relays. If it necessary to meet NEC motor branch protection
approval, eutectic alloy, bi-metal overload relays or an equivalent should
be installed. Refer to article 430 of the NEC and any additional codes for
specific requirements and additional information.