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Rockwell Automation Publication KNX-TD005A-EN-P - October 2021
Motor Overload Protection
Motor Overload Protection
Allen-Bradley servo drives use solid-state motor overload protection that operates in accordance with UL requirements. Motor overload protection
is provided by algorithms (thermal memory) that predict actual motor temperature based on operating conditions as long as control power is
continuously applied.
In addition to thermal memory protection, these drives provide an input for an external temperature sensor/thermistor device, embedded in the
motor, to support the UL requirement for motor overload protection.
Servo drives using DSL (digital servo link) encoder technology require the encoder to perform motor temperature monitoring and transmit the data
over the single motor cable. Kinetix VP (Bulletin VPL, VPF, VPH, VPS, and VPC-B
xxxxx
-Q) motors use DSL technology that performs this function. No
additional wiring is required.
These servo drives meet the following UL requirements for solid-state overload protection.
Refer to your servo drive user manual for the interconnect diagram that illustrates the wiring between your motor and drive.
Motor Overload Protection Trip Point
Value
Ultimately
100% overload
Within 8 minutes
200% overload
Within 20 seconds
600% overload
ATTENTION:
To avoid damage to your motor due to overheating caused by excessive, successive motor overload trips, follow the
wiring diagram provided in the user manual for your motor and drive combination.
