Rockwell Automation 20M LPM15 Liquid-Cooled Adjustable Frequency AC Drive FRN 2.xxx - Manual (Page 112)

D-2 Application Notes
conditions. By identifying motor parameters, the drive can maximize the
torque produced in the motor and extend the speed range at which that
torque can be produced.
This technology is excellent for applications that require a wider speed
range and applications that need maximum possible torque for breakaway,
acceleration or overload. Centrifuges, extruders, conveyors and others are
candidates.
Speed Regulator
The LPM15 drive, regardless of its motor control technology (Volts/Hz or
Sensorless Vector) can be set up to regulate speed. Speed regulation and
torque regulation must be separated to understand drive operation.
The LPM15 can be programmed to regulate speed using the slip
compensation feature. Slip compensation reacts to load changes by
adjusting the drive output frequency to maintain motor speed. Torque
production operates independently. This feature produces speed regulation
of about 0.5% of base speed over a specified speed range (40:1 for V/Hz
and 80:1 for Sensorless Vector). The LPM15 drive does not have the
capability to extend the speed range or tighten the speed regulation below
0.5% because it does not have connections for a feedback device.
Motor Overload For single motor applications the drive can be programmed to protect the
motor from overload conditions. An electronic thermal overload I
2
T
function emulates a thermal overload relay. This operation is based on three
parameters; [Motor NP FLA], [Motor OL Factor] and [Motor OL Hertz]
(parameters 042, 048 and 047, respectively).
[Motor NP FLA] is multiplied by [Motor OL Factor] to allow the user to
define the continuous level of current allowed by the motor thermal
overload. [Motor OL Hertz] is used to allow the user to adjust the frequency
below which the motor overload is derated.
The motor can operate up to 102% of FLA continuously. If the drive had
just been activated, it will run at 150% of FLA for 180 seconds. If the motor
had been operating at 100% for over 30 minutes, the drive will run at 150%
of FLA for 60 seconds. These values assume the drive is operating above
[Motor OL Hertz], and that [Motor OL Factor] is set to 1.00.
Operation below 100% current causes the temperature calculation to
account for motor cooling.