A new approach to field modelling

Language:


RSS Twitter YouTube Blogger Facebook Linkedin

Main > Application > Sample problems

Thermal issues in the design of permanent magnet based electrical motors

36 poles brushless DC motor with NdFeB permanent magnets.

Problem Type:

Plane problem of DC magnetics and heat transfer.

Geometry:

Electric DC motor model

Stator

Name

Parameter

Value

Stator internal diameter

D

400 mm

Stator tooth zone external diameter

DS

430 mm

Stator external diameter

DE

446 mm

Stator axial length

LE

300 mm

Rotor

Name

Parameter

Value

Rotor shaft diameter

DH

355 mm

Rotor core diameter

DN

386 mm

Rotor external diameter

DR

398 mm

Rotor axial length

LX

300 mm

Given:

DC motor power P = 12 kW
Voltage U = 600 V;
Speed Nn = 200 rpm;
Torque Mn = 573 N·m;
Insulation class: F (155°C);
Steel power loss (50 Hz, 1.6 T) pf = 5 W/kg;
Air temperature T = 40°C.

Problem:

Which temperature will afford the magnets under the following working conditions:
Cooling: natural / forced
Load: permanent / periodic (50%)

Results:

Rotor final temperature.

 

Natural convection
Periodic load

Natural convection
Permanent load

Forced convection
Periodic load

Forced convection
Permanent load

Winding

335°C

375°C

142°C

155°C

Magnets

335°C

385°C

125°C

140°C

Hub

342°C

395°C

133°C

147°C

DC motor inductionDC motor temperature

One has to keep in mind the use of forced air circulation as a normal procedure. The controller could offer additional options to pose a limit to currents and/or temperatures.

Download Download simulation files