Magnetizing Equipment for EVs

In line with global trends toward decarbonization, the automotive industry (including automobile and motorcycle manufacturers and parts suppliers) is rapidly shifting from the "reciprocating engine + gasoline" of conventional vehicles to the "motor + battery" of electric vehicles (EVs).

In response to trends in EV motorization, Nihon Denji Sokki Co., Ltd. (NDK) proposes our EV magnetizing solution for automobile manufacturers and automotive parts suppliers.

NDK offers a full range of magnetization-related products that are indispensable for the development and production of drive motors for vehicles. We are contributing to the improvement of EV development and production by automobile manufacturers and their parts suppliers to help drive the EV adoption worldwide.

Magnetizers' Role in Commercializing EVs.

Provides strong and stable magnetization
for EV motor magnets

Size & weight reductions coupled with higher efficiencies and better output for the drive motors at the heart of EVs will be the key for their further commercialization.

In order for a motor to meet the strict technical requirements of EVs, the characteristics of the "magnet," a part that determines performance, must be maximized (Photo 1). Since the magnetic materials from which the magnets are to be produced are not magnetized to begin with, they must be magnetized by magnetizers capable of applying a strong magnetic field.

NDK provides magnetizers and other peripheral equipment which are indispensable for motor-related products of automotive parts (Figure 1). NDK is also actively working to address the new challenges related to magnetization of the EV age, such as higher magnet performance and more complex magnet layouts to offer higher motor performance and improved products.

Photo 1: The rotor and stator
Photo 1: The rotor and stator that make up the motor. Behind the stator is an inverter that converts direct current to alternating current and adjusts the frequency and amount of current during the conversion.
  • Traction motor
  • MG motor generator, etc.
  • ETB electronic throttle
  • Compressors for
    air conditioners
  • EOP electric oil pump
  • Power steering
  • High power alternator
  • e-4WD Motor
  • ESC anti-skid device
  • In-wheel motor

Figure 1: Major parts of EVs, HEVs (Hybrid Electric Vehicles), FCEVs, etc. incorporate a myriad of motors, most of which contain magnets magnetized by magnetizers.

Global Support System Established by Overseas Locations

Getting out the performance and functionality of EVs based on
our rich experience of many domestic and overseas installations

Located in Tokyo (Tachikawa) Japan, NDK is a manufacturer specialized in magnetic application equipment with 70 years of technical experience in research, development and manufacturing.

We are proud to have introduced many of our products to major Japanese automobile manufacturers and other domestic & overseas automobile suppliers who are globally expanding.

In fact, NDK is a sole supplier for one of the largest major domestic automakers (Figure 2)

NDK has approx. 50% share of the entire domestic automotive industry, including reciprocating engine vehicles (gasoline-powered vehicles).

As manufacturers are shifting their focus to EVs, our product deliveries for EVs is rapidly accelerating as well.

In addition, we can offer not only magnetizer and yoke, but also peripheral equipment and various systems.

We specialize in the development and manufacture of customized products that meet customer needs and have developed our overseas business from hubs in Shanghai, China and Bangkok, Thailand (Figure 3).

We provide extensive support for automotive and parts manufacturers in Asia.

We have a wide range of magnetic application products including magnetizer and demagnetizer and can offer total solutions including hardware, software and automation (Figure 4).

Figure 2: 100% share of magnetizer delivery to Japan's largest automaker!
Figure 2: 100% share of magnetizer delivery to Japan's largest automaker!
Figure 3: Global business development with overseas hubs
Figure 3: Global business development with overseas hubs
  • 1 Made in Japan
  • 2 Support capability
  • 3 Numerous achievements
  • 4 High quality
  • 5 Comprehensive capability

Figure 4: NDK's five strengths.
Proud of our core strength, which include technical leadership, product quality and customer support

Advantages & Disadvantages of Magnetization Before and After Assembly

Brings high quality and stable
4 features of NDK's EV magnetization solution

NDK's "EV Magnetizer Solution" is developed, manufactured and inspected entirely in Japan.In particular, we are proud of our quality and product strength that far exceed competitors in the following four areas (Figure 5).

  1. Magnetizing yoke with unrivaled durability
  2. Low power consumption design while maintaining the required magnetic field
  3. Possesses magnetization know-how for any shape of motor parts for EV
  4. Provide both "pre-assembly magnetization" and "post-assembly magnetization" .*

In "pre-assembly magnetization," the magnet is magnetized before being attached to the rotor.Post-assembly magnetization" refers to magnetizing the magnet after the unmagnetized magnet has been attached to the rotor. Pre- and post-assembly magnetization have their own advantages and disadvantages and they should be used differently depending on the manufacturing process and the characteristics of the parts to be magnetized (Table).

Figure 5: Four features of EV magnetizing solution + α
Figure 5: Four features of EV magnetizing solution + α
  • Pre-assembly magnetization

    Advantage: 100% magnetization of magnets possible
    Disadvantage: Magnet damage and worker injury due to sticking when being attached to rotor, etc.
    Required machines and equipment: magnetizing power supply, magnetizing coils
  • Post-assembly magnetization

    Advantage: Installation of magnets on rotor is easy. Productivity increases as the number of magnets increases.
    Disadvantage: 100% magnetization is possible. However, the magnetization ratio may be lower than 100% depending on the magnet position.
    Required machines and equipment: magnetizing power supply, magnetizing yoke

Table: Advantages and disadvantages of pre- and post-assembly magnetization
and equipment required such as magnetizing power supply and magnetizing coils

In addition to capacitor-type "Magnetizing Power Supply" and "Magnetizing Yoke-coils" (Photo 2) that support high voltage and large capacity, we offer diverse products including "magnetizing system," "super multi-pole magnetizing equipment" and "measuring instruments".

In addition to product customization, we have the established support systems both in Japan and overseas.NDK will realize "post-assembly magnetization" as much as possible based on analysis, experience and yoke material selection. There have been many cases where NDK was able to realize post-assembly magnetization that others weren't. Please feel free to contact us.

Photo 2:magnetizing power supplies, magnetizing yokes and magnetizing coils

Photo 2: As we have produced many magnetizing power supplies, magnetizing yokes and magnetizing coils,
we can propose products that satisfy every customer's requirement in magnetizing performance.

Need for Magnetic Field Analysis

The latest computer analysis has led our product
performance to "0" (zero) trouble after purchase.

NDK performs analytic simulations in advance to ensure the best possible magnetization of the rotor in which the customer's magnets are used.

Using the rotor brought to us, we perform the latest computer analysis, and based on the data obtained, we propose the shape and size of the yoke and coil that will enable the most stable magnetization as well as all required system equipment (Figure 6).

Since the effectiveness of the "post-assembly magnetization" can be verified based on analysis data prior to the purchase of the product, we can propose a magnetizer that satisfies the performance required of the customer. Our technological capabilities, spanning many years experience and know-how in the development of magnetically applied equipment and the latest computer analysis technology, enable us to realize the customers' ideal magnetization performance.

Using the magnetizing power supplied by the magnetizing yoke and our proprietary CU1/CU3 charge/discharge control unit  (developed in-house), fine adjustments can be done to meet the customer's requirements, enabling us to offer a highly maintainable product.

Figure 6: On the left is a diagram of the vectors generated in the magnet when the magnetizing yoke is energized (direction of the magnetic field).On the right, the strength of the magnetic field generated is color-coded.
Figure 6: On the left is a diagram of the vectors generated in the magnet when the magnetizing yoke is energized (direction of the magnetic field). On the right, the strength of the magnetic field generated is color-coded. Made possible to produce in the sequence of "prototype → mass production" from the simulation

Full Range of Magnetic Application Equipment

A pioneer in magnetic application equipment
Neodymium magnet molding equipment is also under development

In addition to "Capacitor-type Magnetizer" for high voltage and large capacity, we offer a full line of products including "Super Multi-pole Magnetizer," "Magnetizing Yokes and Coils," "Magnetizing System" and "Measuring Instruments".
We are also working with Dr. Masato Sagawa, the inventor of the neodymium magnet, to develop a "neodymium magnet molding equipment" using a new molding method. Most traction motors, that require high torque including EVs, use neodymium magnets and the demand for molding equipment for these magnets is expected to increase.

Not relying solely on our track record, we are engaging in the development of new products that derive from our unique strengths.

  • Tesla meter

    [Tesla meter]

    Measurement of magnetization of magnets, residual magnetism of steel and pulse magnetic field

  • Flux meter

    [Flux meter]

    Measure the total magnetic flux. Check the magnetization state after magnetization of magnet.

  • Flux separator

    [Flux separator]

    Protects the flux meter from high currents in the search coil

  • Analyzer


    Measure magnetic flux density and magnetic flux quantity distribution on magnet surface and display them in 2D/3D

  • Demagnetizer


    Equipment to remove magnetism generated in metallic substances

  • NdFeB magnet molding equipment

    [NdFeB magnet molding equipment]

    Neodymium has multiple applications in automobiles, robotics, sensors, medical devices etc.

  • Thickness Gauge

    [Thickness Gauge]

    Device to measure the wall thickness of a material. Check if the material is in compliance with the industrial standards and regulations.

  • Impregnation


    Sealing treatment prevents leakage of gases and liquids and ensures part strength before plating and painting.

Customer Service Flow (steps till the delivery)

Even customers who are new to magnetization are at ease
Full support by experienced technical sales staff

NDK has established a complete customer support system tailored to your needs, specifications and convenience. Our experienced technical sales staff is dedicated to fulfill your requirements and can provide information on purchase, analysis data, yoke prototyping and delivery(Figure 7). Our testing room is fully capable of performing a wide range of tests. Your workpiece is quickly analyzed and the most appropriate specifications and designs are determined.

Since our service area covers all of Japan, customers who have offices, factories and other sites throughout the country can feel secure when requesting our services. We also support our overseas customers through our local offices and trading companies.

Figure 7: NDK's customer support flow
Figure 7: NDK's customer support flow

70 years of supporting Japan's motorization.
NDK contributes to decarbonization
through its contribution to EV deployment.


Brushless motor,
Rotor and stator

A motor called a "brushless motor" is mainly used to drive EVs (Figure 8). It consists of two parts: 1. the rotor, which rotates when an electric current is applied, and 2. the stator, which rotates the rotor. In the rotor, neodymium magnets are mainly used. When power is supplied to an electromagnet, a repulsive magnetic field is generated around the magnet which has a rotation axis at its center. The interaction of the forces of attraction between N and S poles and the forces of repulsion between the same poles causes a magnet to rotate.

Figure 8: Cross-sectional view of the brushless motor
Figure 8: Cross-sectional view of the brushless motor. The rotor is placed in the center and when electric power flows into the stator, which incorporates an electromagnet, the rotor begins to rotate.

EV (Electric Vehicle)
Eco car

An EV is an electric vehicle (Figure 9), which runs on power obtained by rotating an electric motor. The advantages of these vehicles are that they do not use gasoline nor emit carbon dioxide while running and thus their share in the global market is rapidly increasing, helping in eliminating fossil fuels and combating global warming. Other types of eco-cars include

  • Hybrid Vehicles (HV): Utilize two types of power, an electric motor and an engine (to achieve low fuel consumption)
  • Plug-in Hybrid Vehicles (PHVs): HVs that can be charged from an external power supply
  • Fuel Cell Vehicles (FCVs): Powered by electricity generated from hydrogen and oxygen
  • Natural Gas Vehicles (e.g., CNG): Powered by Natural Gas as fuel

*Rare-earth magnets are mainly used in the motors for driving and power generation in EVs and various eco-cars.

Figure 9:  EVs consist of three major parts
Figure 9: EVs consist of three major parts: a drive motor, a battery and a power control unit. The number of motors used is increasing in other parts as well.


To magnetize a permanent magnet, it is necessary to provide a magnetic field strong enough to reach the saturation point of the maximum magnetic flux density of the magnet material (magnetic material substance). The energy supply device that produces this high magnetic field is the "Magnetizer". Magnetizers are used to magnetize magnets in combination with magnetizing yokes and coils (Figure 10). The internal capacitor is charged from a commercial power supply and the energy is used to generate a high magnetic field by energizing the magnetizing yoke with a pulsed current that in turn magnetizes the permanent magnet.

Figure 10:  Configuration of magnetizer
Figure 10: Configuration of magnetizer

Neodymium magnet

A neodymium magnet is one of the rare-earth magnets whose main constituents are neodymium, iron and boron (Figure 11). It is the most powerful permanent magnet, surpassing the samarium-cobalt alloys that existed before it. Since the material was inexpensive and could be mass-produced, it played a decisive role in the dawn of the personal computer age. It is also used as a core material in eco-energy technologies such as wind power generators and electric vehicles. It was invented by Dr. Masato Sagawa in 1984. Nihon Denji Sokki Co., Ltd. is also working with Dr. Sagawa to develop a neodymium magnet molding system.

Figure 11: Industrial neodymium magnet
Figure 11: Industrial neodymium magnet. A wide variety to accommodate the size and shape of motors and other equipment
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