WOLFRAM SYSTEMMODELER

Friction

Model of angular velocity dependent friction losses

Wolfram Language

In[1]:=
SystemModel["Modelica.Electrical.Machines.Losses.Friction"]
Out[1]:=

Information

This information is part of the Modelica Standard Library maintained by the Modelica Association.

The friction losses are considered by the equations

   tau / tauRef = (+w / wRef) ^ power_w    for w > +wLinear
 - tau / tauRef = (-w / wRef) ^ power_w    for w < -wLinear

with

  tauRef * wRef = PRef

being the friction torque at the reference angular velocity wRef. The exponent power_w is approximately 1.5 for axial ventilation and approximately 2.0 for radial ventilation.

For stability reasons the friction torque tau is approximated by a linear curve

  tau / tauLinear = w / wLinear

with

  tauLinear = tauRef*(wLinear/wRef) ^ power_w

in the range -wLinear ≤ w ≤ wLinear with wLinear = 0.001 * wRef. The relationship of torque and angular velocity is depicted in Fig. 1

frictiontorque.png
Fig. 1: Friction loss torque versus angular velocity for power_w = 2

See also

FrictionParameters

If it is desired to neglect friction losses, set frictionParameters.PRef = 0 (this is the default).

Parameters (2)

useHeatPort

Value: false

Type: Boolean

Description: =true, if heatPort is enabled

frictionParameters

Value:

Type: FrictionParameters

Description: Friction loss parameters

Connectors (3)

flange

Type: Flange_a

Description: Shaft end

support

Type: Flange_a

Description: Housing and support

heatPort

Type: HeatPort_a

Description: Optional port to which dissipated losses are transported in form of heat

Components (1)

frictionParameters

Type: FrictionParameters

Description: Friction loss parameters

Used in Components (3)

PartialBasicMachine

Modelica.Electrical.Machines.Interfaces

Partial model for all machines

PartialBasicInductionMachine

Modelica.Magnetic.FundamentalWave.Interfaces

Partial model for induction machine

PartialBasicMachine

Modelica.Magnetic.QuasiStatic.FundamentalWave.BasicMachines.BaseClasses

Partial model for quasi static multi phase machines