The Material & Thermal section in Motor Wiz allows users to define and manipulate the electromagnetic and thermal characteristics of the motor. These parameters are crucial for accurate simulation, performance optimization, and real-world validation. Proper selection of materials and thermal considerations directly impacts efficiency, reliability, and motor lifespan.
From a user’s perspective, this section bridges the gap between theoretical motor design and practical implementation. Engineers can experiment with material grades, thermal limits, and insulation strategies to meet design goals such as high torque density, low losses, or thermal stability.
i. Material Selection
Motor Wiz provides a comprehensive library for stator lamination, rotor lamination, magnets, shafts, wires, frames, and insulation materials. Each material selection comes with pre loaded properties such as electrical resistivity, thermal conductivity, saturation flux density, and mechanical strength.
Stator Lamination Material
Stator lamination materials are high-permeability electrical steels that minimize core losses and improve motor efficiency. These materials are selected based on factors such as thickness, electrical resistivity, and performance under varying frequencies. Common materials include:
M19: High-grade silicon steel with low core loss and high permeability.
M400-50A, M800-50A: Standard electrical steels with different loss characteristics for industrial applications.
M19_29Ga: Variant of M19 with thinner gauge, reducing eddy current losses.
M270-35A, M235-35A: Low-loss electrical steels for improved efficiency.
M530-65A: Higher thickness variant, used for cost-effective solutions.
Rotor Lamination Material
Rotor lamination materials are similar to stator materials but optimized for mechanical and electromagnetic performance. Common types:
M19, M400-50A, M800-50A, M19_29Ga: Silicon steels with varying thickness and loss characteristics.
M270-35A, M235-35A: Low-loss steels for high-performance applications.
M530-65A: Thicker grade for cost-effective rotor designs.
Magnet Material
Magnet materials determine the strength and temperature resistance of the motor. Neodymium magnets are commonly used for high-performance applications. Key variants:
Magnet_42H to Magnet_52M: High-energy neodymium magnets with varying coercivity and remanence.
Magnet_40SH to Magnet_52SH: High-temperature neodymium magnets (SH = Super High Temp).
Magnet_45M, Magnet_48M, Magnet_50M, Magnet_N50: Medium coercivity grades for balanced performance.
MagnetPrius: Specialized magnet used in Toyota Prius motors.
N42UH: Ultra-high-temperature neodymium magnet for extreme conditions.
Shaft Material
Shaft materials provide mechanical strength and fatigue resistance:
M19 to M530-65A: Electrical steels with varying magnetic properties for applications where flux conduction is required.
M400-50A_Jaguar: High-performance steel designed for EV applications.
Wire Material
Wire materials affect electrical resistance and heat dissipation in windings:
Copper1, Copper2: High-purity copper wires with slight variations in conductivity and mechanical properties to optimize efficiency.
Frame Material
Motor frames must be strong, thermally conductive, and resistant to environmental conditions:
M19 to M530-65A: Different electrical steels used based on cost, weight, and thermal performance.
Insulator Material
Insulator1: High-grade electrical insulation to prevent short circuits and improve thermal resistance in motor windings.
ii. Thermal Parameters
Thermal properties in Motor Wiz allow users to predict and manage temperature rise, ensuring safe operation without degrading material or reducing efficiency.
Slot Paper Thickness
Refers to the insulation material between stator slots and copper windings.
Typically ranges from 0.1 mm to 0.3 mm; too thick reduces slot space for copper.
Influences thermal resistance—thicker paper slows heat transfer from winding to core.
Must withstand high temperatures and electrical stress without degradation.
Ambient Temperature
The surrounding temperature where the motor operates, typically set between 25°C–45°C.
Directly affects cooling efficiency and the initial thermal condition of the system.
Higher ambient temperatures require better heat dissipation to avoid overheating.
It’s a key input for thermal simulations and real-world motor performance estimation.
Assumed Winding Temperature
Estimated operating temperature of the copper winding during peak performance.
Usually assumed between 120°C–180°C depending on insulation class (Class F or H).
Critical for calculating resistance variation and copper losses.
Impacts motor lifetime, as excessive temperatures degrade insulation and copper quality.
Convective Heat Transfer Coefficient (HTC)
The convective heat transfer coefficient affects how fast the heat is transferred from the motor to the surrounding environment. It depends on the process of transfer as follows:
Natural convection: 5 – 25 W/m²-K
Forced convection: 25 – 250 W/m²-K
Fin Area Factor
Represents the enhancement of surface area due to fins in motor housing.
A factor greater than 1 implies fins are present, increasing heat dissipation capacity.
Example: A fin area factor of 2 means twice the surface area compared to a plain surface.
Helps achieve better passive cooling, especially useful in air-cooled motors.
Yoke-Housing HTC
Describes thermal conductance between the stator yoke and motor housing.
Important when heat flows from the stator core to the external environment.
Typical values range from 200–1000 W/m²K, depending on bonding quality and materials.