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Are Permanent Magnet Motors AC or DC?


The electric motor makes it feasible to generate motion by using electricity as the driving force. They are a broad class of machines that provide power to a startling number of applications. Today, they reign supreme in automation, manufacturing, commercial items, and other domains. This article will look at the permanent magnetic motor, the permanent magnet motor types, and many more which contribute to the adaptability of these motors, which originate from the fact that many different kinds of electric motors are accessible. 

Even though it was created early, this motor is rapidly becoming a competitive alternative to industry standards owing to the developments that have occurred in the 21st century. This article will study this motor, its operating principles, and its applications. Our findings will demonstrate why this motor has garnered such a great deal of interest in recent years.

What are Permanent Magnet Motors?

Interestingly, permanent magnet motors are sophisticated motor that, in terms of design, is comparable to induction motors and servo motors. They are made up of a rotor, the moving component linked to the motor’s output shaft, and a stator, which is the exterior housing of the motor. Permanent magnet motors, like other AC motors, generate torque by exploiting the physics of electromagnetism. However, unlike other AC motors, permanent magnet motors incorporate permanent magnets (typically rare earth magnets such as neodymium magnets) into the motor’s rotor.

This design differs from most conventional electric motors, in which the rotor either creates its magnetic field by induction or using a DC power source or is made up of a ferromagnetic metal. When a permanent magnet motor’s magnets are correctly placed around the stator, they can deliver speeds equal to the excitation current frequency. As a result, this kind of motor is known as a synchronous motor or permanent magnet AC motor. Because these motors need to be combined with an electrical component that evens out the torque produced by this motor, the design of these machines has only lately begun to mature into something that might be considered a realistic option.

How do Permanent Magnet Motors Work?

The basic workings of a permanent magnet motor are very similar to those of most electric motors. The outer stator of the motor contains windings of coils supplied with power by an external source. Then the rotor freely rotates based on the forces imparted by the stator coils. Permanent magnet motors are based on many fundamental ideas as induction motors. This does not mean that they are just AC motors; throughout their existence, they have been used as permanent magnet DC motors (PMDCM) for a variety of quite modest applications.

On the other hand, PMDCMs have a relatively low amount of power. These motors come in larger sizes, have higher horsepower ratings, and can compete with induction motors equally in terms of their power, efficiency, and several applications.

The stator windings’ rotational magnetic field (RMF) acts onto the permanent magnets inside the rotor of PMACMs, which causes them to be repelled into rotational motion. This characteristic is what distinguishes PMACMs from other types of AC motors. This is a departure from the design of other rotors, in which the magnetic force has to be induced or created inside the rotor housing, necessitating a higher current. PMACMs are typically more efficient than induction motors since the rotor’s magnetic field is permanent and requires no power source to be utilized for its creation. On the other hand, induction motors require a power source to generate the magnetic field. Because of this, for these motors to function, they need to be paired with a variable frequency drive, also known as a permanent magnet drive (PM drive), which is a kind of control system that evens out the torque generated by the motors.

The PM drives regulate torque and current by switching the current on and off to the stator windings at key periods of rotor rotation. It then utilizes this data to compute rotor position and, therefore, the speed of the shaft output. They are known as synchronous machines because the speed at which they rotate is identical to that of the RMF. As a result of the fact that these machines are continually being improved upon and are still relatively new, the particular functioning of every given PMACM is, for the time being, virtually unique to each design.

Are Permanent Magnet Motors Alternating Current or Direct Current?

Permanent magnets may be used in both AC and DC equipment. Permanent magnets are used as field excitation in a variety of motor types. Permanent magnet synchronous motors (PMSM) are also permanent magnet AC motors. Permanent magnets are utilized in the rotor of alternating current motors. The goal is to align (and generate torque) with the revolving MMF created by the stator winding. Permanent magnets are used to produce a magnetic field in DC motors. There exist no rotational MMF. Therefore, net torque is generated by an alternating current at the armature formed by the commutator.

The Benefits of PMDC Motors

Smaller in Size

As previously said, PMDC motors are often smaller in size than other motors, but this does not imply that they are less functional. They are, in fact, ideal for tiny applications such as air conditioning units, windshield wipers, and even electric toothbrushes. This also aids mobility, making them easier to carry throughout the world.

Permanent magnet motors may be utilized in various sectors because they can be configured to satisfy various criteria, such as size and power. A PMDC motor is just as likely to be found in a computer drive as in a child’s toy.

High Starting Torque

PMDC motors, like other DC motors, have a high starting torque, making them ideal for various applications. Despite their lower speed, these motors are very dependable. When paired with one of our gearboxes, they provide the perfect geared motor option.


Permanent magnet motors are a dependable and cost-effective solution for your application due to their smaller size and absence of field windings. We can build a great magnetic solution for your application at ROBO Magnetic, guaranteeing you have a long-lasting motor that operates to your exact specifications.

Any ROBO magnetic permanent magnet DC motor may be constructed to meet your power needs, whether you use it as a stand-alone motor or in conjunction with parts.

Magnets Used in Permanent-Magnet Motors

Rare-earth elements are the 30 metals in the periodic table’s sometimes overlooked lengthy center two rows; they are employed in a wide range of current applications, such as the case of permanent magnet motors. Rare-earth magnets are extremely strong alloys with crystalline structures that exhibit high magnetic anisotropy – that is, they easily align in one direction but resist alignment in others.

Permanent magnets are utilized in MRI machines, portable electronic hysteresis clutches, gadgets, accelerometers, and rotary and linear motors using permanent magnets.

Sintered and bonded magnets are two types of permanent magnets extensively utilized in permanent magnet motors. AlNiCo, ferrite, samarium cobalt, neodymium iron boron, and more common kinds are listed below. 

Neodymium Magnets

NdFeB magnets are neodymium and iron oxide alloys. NdFeB permanent magnets have been extensively employed in contemporary industrial and electronic technology due to their extraordinarily high magnetic energy product and coercive force, as well as the benefits of high energy density. This allows for smaller, lighter, and thinner equipment such as permanent magnetic motors, instruments, electroacoustic motors, magnetic separation, and magnetization. Because neodymium magnets have a high concentration of neodymium and iron, they rust easily. One of the greatest remedies for neodymium magnet corrosion is surface chemical passivation.

Permanent Magnet DC Motor Applications

PMDC motors are utilized in various applications, from fractions to several horsepowers. They are designed to provide up to 200 kW of power for usage in various industries. The applications listed below are examples.

PMDC motors are mostly used in vehicles to power windshield wipers and washers, raise lower windows, and drive blowers for heaters and air conditioners, among other things.

They’re also found in hard disks.

These motors are also employed in the toy industry.

Electric toothbrushes, portable vacuum cleaners, and food mixers employ PMDC motors.

Used in portable electric tools, including drills and hedge trimmers.

Permanent Magnet Synchronous Motor Applications

The benefits of permanent magnet synchronous motors are their simple construction, compact size, great efficiency, and high power factor. It has been widely used in the rubber industry (internal mixer), the metallurgical industry (ironmaking plant & sintering plant), the ceramic industry (ball mill), the textile industry (double twist machine, spinning frame), the petroleum industry (pumping unit), and other industries that require a medium or low voltage motor.


Thank you for taking the time to read this article. We hope our article is great and has given you a better knowledge of the benefits and uses of permanent magnet motors. We believe you know that permanent magnet motors can be either DC or AC. If you are interested in learning more about permanent magnets, we recommend you visit ROBO Magnetic.

ROBO Magnetic, a global magnet provider, has been active in magnet manufacture and sales for over 16 years. We offer consumers high-quality permanent neodymium magnets at a low cost.


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ROBO Magnetic Product Team

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