X-Factor

Introduction

The X-Factor panel allows the user to define calibration factors to tune the thermal modeling on specific resistances.

The calibration factors set in this panel are considered in the results shown in Cooling subset, Internal panel environment, and the TEST environment.

The X-Factor panel also contains a set of parameters defining the internal cooling (coolants temperature and rotor speed), allowing the user to evaluate the thermal model embedded.

The effect on every X-Factor value can be directly seen in the outputs displayed in the internal cooling panel.

Table 1. Internal cooling – X-Factor design area. The example shown corresponds to a SMPM IR machine


1 Table of the calibration factors allowing the user to tune the thermal modeling. Each X-factor tunes a set of resistances. The mapping showing the impact of each X-factor is explained in the below dedicated section.
2 Machine maximum speed.

It is the maximum rotation speed for which the convection curves will be evaluated in the internal cooling datasheet.
3 Internal fluid temperature
It is the temperature used in the internal cooling panel to evaluate the convection and the radiation occurring inside the machine. All the results shown in the internal cooling panel use this temperature as the temperature of the internal fluid enclosed in the machine. Most of the curves shown in the internal cooling panel are plotted for a range of temperatures going from this reference temperature to 150 K above it.
Note: This temperature is only used for the model evaluation in the internal cooling panel. This temperature does not affect the test computations, where the internal fluid temperature is found by the nonlinear solving during the solving of the test.

X-Factor mapping

Each calibration factor impacts a specific set of resistances, among the most important thermal resistances of the thermal modeling of a machine.

Table 2. Internal cooling – Calibration factors input table – All machine types


1 Magnetic circuit-frame
This calibration factor tunes the total resistance between the stator yoke and the frame. This total resistance is composed of two resistances in series:
  • The conduction through the stator yoke until its border, computed by finite elements.
  • The conduction through the imperfect interface between the stator magnetic circuit and the frame.
2 Magnetic circuit-slot
This calibration factor tunes each of the thermal resistances linking the stator core to the winding. Each of these resistances consists of several resistances in series:
  • The conduction through the stator core until the slot border, computed by finite elements.
  • The conduction through the imperfect interface between the magnetic circuit and the liner
  • The conduction through the slot (using the equivalent conductivity defined in the settings “Slot model” of the “Internal cooling” panel).
3 Connection Side end winding – slot

This calibration factor tunes the conduction resistance between the slots (meaning In-slot winding) to the Connection Side end winding.
4 Opposite Connection Side end winding – slot.

This calibration factor tunes the conduction resistance between the slots (meaning In-slot winding) to the Opposite Connection Side end winding.
5 Connection Side end space
This calibration tunes all the resistances involved in thermal exchanges with or through the Connection Side end space fluid:
  • The thermal resistances from each part composing the stator and the rotor to the Connection Side end space fluid (each of these resistances being composed of conduction through the machine depth added to convection at the rotor and stator ends)
  • The convection resistance between the Connection Side end winding and the Connection Side end space fluid.
  • The thermal resistance between the Connection Side end space fluid and the frame and end cap surfaces on the Connection Side.

The radiation resistances from the stator end, rotor end, and end winding to the frame and the end cap surfaces on the Connection Side.
6 Opposite Connection Side end space
This X-factor tunes every resistance involved in thermal exchanges with or through the Opposite Connection Side end space fluid:
  • The thermal resistances from each part composing the stator and the rotor to the Opposite Connection Side end space fluid (each of these resistances being composed of conduction through the machine depth added to convection at the rotor and stator end).
  • The convection resistance between the Opposite Connection Side end winding and the Opposite Connection Side end space fluid.
  • The thermal resistance between the Opposite Connection Side end space fluid and the frame and end cap surfaces on the Opposite Connection Side.

The radiation resistances from the stator end, rotor end, and end winding to the frame and the end cap surfaces on the Opposite Connection Side.
Table 3. Internal cooling – Calibration factors input table – All machine types


7 Airgap
This calibration factor tunes every resistance involved in thermal exchanges with or through the airgap fluid:
  • The conduction through the stator yoke and slot until the airgap border, computed by finite elements.
  • The conduction through the rotor yoke and magnets until the airgap border, computed by finite elements.
  • The convection from the airgap border to the airgap fluid.

The radiation from every rotor component having a border along the airgap to every stator component having a border along the airgap.
8 Magnetic circuit-shaft
This calibration factor tunes the total resistance between the rotor yoke and the shaft. This total resistance is composed of two resistances in series:
  • The conduction through the rotor yoke until its border, computed by finite elements.
  • The conduction through the imperfect interface between the rotor magnetic circuit and the shaft
9 Bearings

This calibration factor tunes the resistances existing across the Connection Side bearing and the Opposite Connection Side bearing.

These resistances are the resistances computed directly from the bearing equivalent airgap thickness set by the user in Interface settings.
Table 4. Internal cooling – Calibration factors input table – SMPM machines


1 Magnetic circuit-magnet (only for SMPM machines)
For every existing magnet, this calibration factor tunes the total resistance existing between this magnet and every component of the rotor magnetic circuit around it. Each of these resistances is composed of three resistances:
  • The conduction through the rotor yoke until the magnet border, computed by finite elements.
  • The conduction through the imperfect interface between the rotor magnetic circuit and the considered magnet.
  • The conduction through the magnet until its border, computed by finite elements.
Table 5. Internal cooling – Calibration factors input table – IMSQ machines


1 Magnetic circuit-bar
For every existing bar, this calibration factor tunes the total resistance existing between this bar and every component of the rotor magnetic circuit around it. Each of these resistances is composed of three resistances:
  • The conduction through the rotor yoke until the bar border, computed by finite elements.
  • The conduction through the imperfect interface between the rotor magnetic circuit and the considered bar.
  • The conduction through the bar until its border, computed by finite elements
Table 6. Internal cooling – Calibration factors input table – SMWF-ISP machines


1 Magnetic circuit-bar
For every existing bar, this calibration factor tunes the total resistance existing between this bar and every component of the rotor magnetic circuit around it. Each of these resistances is composed of three resistances:
  • The conduction through the rotor yoke until the bar border, computed by finite elements.
  • The conduction through the imperfect interface between the rotor magnetic circuit and the considered bar.

    The conduction through the bar until its border, computed by finite elements

2 Magnetic circuit-field winding
This calibration factor tunes each of the thermal resistances linking the rotor core to the field winding. Each of these resistances consists of several resistances in series:
  • The conduction through the rotor core until the field winding border, computed by finite elements.
  • The conduction through the imperfect interface between the magnetic circuit and the insulation region.

The conduction through the coil (using the equivalent conductivity defined in the settings “Field winding model” of the “Internal cooling” panel).
3 Connection Side field end winding – field winding

This calibration factor tunes the conduction resistance between the field winding (meaning In-coil winding) and the Connection Side end winding.
4 Opposite Connection Side field end winding – field winding

This calibration factor tunes the conduction resistance between the field winding (meaning In-coil winding) and the Opposite Connection Side end winding.