Application of permanent magnet motors in elevator traction machines

In the elevator industry, the use of permanent magnet (PM) motors in traction machines represents a significant technological advancement. These motors offer numerous benefits, including improved efficiency, compact design, and lower maintenance costs, which are crucial for modern elevator systems. This blog explores the application of PM motors in traction machines and the critical factors in selecting the appropriate magnets.

How do magnets work in elevators?

Permanent magnet motors have become a preferred choice for traction machines in elevators due to their high efficiency and performance. Unlike traditional induction motors, PM motors use permanent magnets to generate a magnetic field, eliminating the need for additional power sources to maintain magnetism. This inherent efficiency results in several operational benefits:

·  High Efficiency: PM motors typically achieve higher efficiency rates compared to their induction counterparts. This translates to lower energy consumption, which is vital for the overall cost-effectiveness of elevator operations.

·  Compact and Lightweight Design: The high power density of PM motors allows for a more compact and lightweight design, making them ideal for space-constrained applications like elevators.

·  Precise Control: PM motors provide excellent control over speed and torque, ensuring smooth and reliable elevator operation.

·  Reduced Maintenance: With fewer moving parts and no need for brushes or commutators, PM motors require less maintenance, leading to lower long-term operational costs.

Types of Magnets Commonly Used in Traction Machines

1. NdFeB Magnets:

Neodymium Iron Boron (NdFeB) magnets are currently the strongest permanent magnets available in the market, with high magnetic energy and high remanence. Their energy product can reach over 50 MGOe. Due to their superior performance, NdFeB magnets are widely used in permanent magnet motors in traction machines, providing a strong magnetic field that enhances motor efficiency and power output.

Newland Magnetics offers a full range of NdFeB magnets from H to SH, strictly meeting national standards. Our excellent magnetic performance curves make us a trusted manufacturer of magnetic solutions for our clients.

2. SmCo Magnets:

Samarium Cobalt (SmCo) magnets have high magnetic energy and excellent temperature stability, capable of operating at temperatures up to 350°C, making them suitable for extreme working conditions. They also have strong corrosion resistance. SmCo magnets are ideal for permanent magnet motors that need to operate in high-temperature environments, ensuring reliable motor performance in harsh conditions, including certain specialized traction machine applications.

3. Ferrite Magnets:

Ferrite magnets have lower magnetic performance but are cost-effective and corrosion-resistant, suitable for mass production. They are typically used in low-cost applications, making them appropriate for traction machines with lower performance requirements.

4. AlNiCo Magnets:

Aluminum Nickel Cobalt (AlNiCo) magnets offer good temperature stability and corrosion resistance, though their magnetic performance is lower compared to NdFeB and SmCo magnets. AlNiCo magnets are used in applications that require high-temperature stability but do not demand high magnetic performance.

These magnets provide a range of options to meet different needs in traction machine applications, from high-performance motors to cost-effective solutions.

How to Choose the Type of Magnet for Permanent Magnet Motors?

The performance of permanent magnet motors in elevators largely depends on the quality and characteristics of the magnets used. The most commonly used type of magnet in these applications is Neodymium Iron Boron (NdFeB) magnets, known for their strong magnetic properties and durability.

Key Considerations for Magnet Selection:

Magnetic Strength: NdFeB magnets have very high magnetic strength, which is crucial for generating the required torque in traction machinery. Their ability to maintain a strong magnetic field ensures efficient motor performance.

Thermal Stability: Elevators operate under various temperature conditions, so the magnets must retain their magnetic properties over a wide temperature range. NdFeB magnets offer excellent thermal stability.

Corrosion Resistance: Exposure to environmental factors can lead to corrosion, affecting the magnet’s performance. NdFeB magnets are usually coated with protective layers such as nickel, zinc, or epoxy to enhance their corrosion resistance.

Cost-Effectiveness: Although NdFeB magnets are more expensive than other types, their superior performance justifies the investment. The overall benefits of NdFeB magnets in terms of efficiency, reliability, and maintenance savings outweigh the initial costs.

The application of permanent magnet motors in traction machines represents a significant advancement in elevator technology. By choosing the right magnets, particularly NdFeB magnets, manufacturers can achieve exceptional performance, efficiency, and reliability. As the demand for efficient and reliable elevator systems continues to grow, the role of permanent magnet motors in traction machines will become increasingly important. At Newland Magnetics, we are dedicated to providing high-quality magnetic solutions to meet the evolving needs of the elevator industry.