FrictionModel of angular velocity dependent friction losses 
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
Fig. 1: Friction loss torque versus angular velocity for power_w = 2 
If it is desired to neglect friction losses, set frictionParameters.PRef = 0
(this is the default).
useHeatPort 
Value: false Type: Boolean Description: =true, if heatPort is enabled 

frictionParameters 
Value: Type: FrictionParameters Description: Friction loss parameters 
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 
frictionParameters 
Type: FrictionParameters Description: Friction loss parameters 

Modelica.Electrical.Machines.Interfaces Partial model for all machines 

Modelica.Magnetic.FundamentalWave.Interfaces Partial model for induction machine 

Modelica.Magnetic.QuasiStatic.FundamentalWave.BasicMachines.BaseClasses Partial model for quasi static multi phase machines 