Values From Drive Column - Emerson EZMotion User Manual

The synchronous speed of the motor is the rated speed without slip taken into account.
Rotor Inertia
This parameter specifies the inertia of the motor rotor. The range is 0.000010 to 90.000000 kg*m^2. The SM-EZMotion
module uses this parameter to interpret the "Inertia Ratio" parameter found on the Tuning view. "Inertia Ratio" is specified as a
ratio of reflected load inertia to motor inertia.
Rated Frequency
This parameter specifies the Rated Frequency of the motor. The applied frequency will directly affect the speed of the motor.
This value is usually printed on the motor nameplate as well as on a motor data sheet provided by the motor manufacturer.
The range for this parameter is 0.0 to 1250.0 Hz.
Phase Resistance SP
Specifies the phase resistance of the motor. You can determine this value by measuring the resistance between any motor
phase and ground with an ohmmeter. The range is 0.000 to 30.000 Ohms. The motor manufacturer will typically provide the
phaseResistance data.
NOTE
This parameter is not the same as the phaseResistance parameter found in the .ddf file used for En/Epsilon/MDS drives. Do
not copy this value from motor files created for En, Epsilon, or MDS drives.
Transient Inductance
Specifies the phase inductance of the motor. This is the inductance measured from phase to ground, NOT phase-to-phase.
The range is 0.00 to 5000.00 mH.
Max Operating Speed
This parameter specifies the maximum speed of the motor when used with a variable speed drive to achieve velocities over
the rated base speed of the motor.
This parameter is not to be confused with the Full Load Rated Speed of the induction motor. The motor manufacturer typically
provides this value. The range for the Max Operating Speed is 40000.0 rpm (depending on encoder resolution).
Full Load Rated Speed
This parameter specifies the rated speed of the motor that would be achieved if the motor were attached directly to the rated
line voltage. The motor manufacturer typically provides this information. The range for the Full Load Rated Speed is 0.0 to
40000.0 rpm (depending on encoder resolution).
Some manufacturers refer to this parameter as Base Speed, Base RPM.
Thermal Time Constant
Specifies the Thermal Time Constant of the motor. This parameter is used by the Unidrive SP for thermal protection of the
motor. The drive models the temperature of the motor using a formula that generates an overload accumulator value. The
formula is a function of the Thermal Time Constant. When the accumulator reaches 100%, the drive can trip or foldback
depending on other drive settings. For more information on the Thermal Time Constant, please refer to the Unidrive
SPAdvanced User Guide (parameters 4.15, 4.16, and 4.19).
Rated Power Factor
This parameter specifies the motor rated full load power factor. Power Factor is the angle between the motor voltage and
motor current vectors. This parameter can be provided by the user, or can be measured using the Auto-Tune feature of the
Unidrive SP (described later). The range for the Power Factor parameter is 0.000 to 1.000.
Stator Inductance
This parameter specifies the motor stator inductance and is defined as the inductance of the motor stator when rated flux is
applied. This parameter is used to create velocity loop gains for the SM-EZMotion module and Unidrive SP. This value can be
provided by the motor manufacturer, or can be measured using the Auto-Tune feature of the Unidrive SP (See Run Auto-Tune
Button on page 52). The range for the Stator Inductance is 0.00 to 5000.00 mH.
Motor Kt
This parameter specifies the torque constant of the motor, which is defined as the amount of torque produced per Amp. The
units for this parameter are (N*m) / Amp. This parameter can be provided by the motor manufacturer, or can be measured by
using the Auto-Tune feature (explained later). The range for this parameter is 0.00 to 500.00 Nm/A.
Saturation Breakpoint 1
The rated level of flux in most induction motors causes saturation. Therefore, the flux against flux producing current
characteristic is non-linear. The effects of saturation are to cause a step increase in torque when operating in torque mode as
the speed increases into the field- weakening region. The user can simulate the non-linear behavior by defining two
breakpoints on the flux vs. magnetizing current curve. This information is often not provided by the motor manufacturer, but
can be measured by using the Auto-Tune feature (See Run Auto-Tune Button on page 52). The range for the Saturation
Breakpoint is 0 to 100% of rated flux.
For more information on the Saturation Breakpoint parameter, please refer to the Unidrive SP Advanced User Guide.
Saturation Breakpoint 2
See Saturation Breakpoint 1.
8.2.5

Values from Drive Column

The Values from Drive column is a group of parameters that are constantly being read from the Unidrive SP. The theory of
operation is that the user will often perform an Auto-Tune function that reads/measures/calculates data. The results of those
measurements are read from the drive and displayed in the Values from Drive column. Once they are displayed in PowerTools
EZMotion User/Programming Guide
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