Types of Electric Motors — A Complete Guide from Induction to BLDC to Axial Flux

Published: 9 October 2026 · 12 min read · By Venugopal K N, Director, SNV Stamping Solutions Pvt Ltd

If you work anywhere in the motor industry — whether you make fans, pumps, mixer grinders, EVs, or industrial drives — you deal with electric motors every day. But how many of us really understand the full range of motor types available in the market today? And more importantly, how the choice of motor type decides what kind of stator laminations, rotor laminations, and materials go inside it?

This article is a practical, engineer-to-engineer guide. We will walk through every major type of electric motor — from the century-old induction motor to the latest axial flux designs. For each type, we explain the construction, the rotor and stator design, the winding type, the magnet type (if any), and what kind of laminations it needs. Whether you are a motor designer, a procurement engineer sourcing laminations, or a business owner exploring which motor segment to enter — this guide covers it all.

1. AC Induction Motors — The Workhorse of Industry

The induction motor was invented by Nikola Tesla in the 1880s and is still the most widely used motor in the world. It runs on AC power and uses electromagnetic induction to spin the rotor — no magnets, no brushes, no commutator.

How It Works

The stator carries copper or aluminium windings in its slots. When AC current flows through these windings, it creates a rotating magnetic field. This rotating field induces current in the rotor bars, which creates its own magnetic field. The interaction between these two fields makes the rotor spin. The rotor always turns slightly slower than the stator field — this difference is called "slip."

Rotor Types: Squirrel Cage vs Wound Rotor

Squirrel cage rotor: This is the most common type. The rotor has aluminium or copper bars cast or inserted into slots in the rotor lamination stack. The bars are short-circuited at both ends by rings, forming a cage shape. There is no external electrical connection to the rotor — it is completely self-contained.

Wound rotor: Instead of bars, the rotor has actual copper windings in its slots, connected to slip rings on the shaft. External resistors can be connected through the slip rings to control starting torque and speed. Wound rotors are used in cranes, hoists, and large compressors where high starting torque is needed.

Copper Rotor vs Aluminium Rotor — Why It Matters

This is one of the most important decisions in induction motor design:

Aluminium rotor bars are the standard choice for most applications. Aluminium is easy to die cast, cheaper than copper, and lighter. The casting process is well-established — molten aluminium is injected into the rotor lamination stack at high pressure, filling every slot and forming the end rings in one shot. Most single-phase induction motors in India — ceiling fans, table fans, pedestal fans, mixer grinders — use aluminium rotors.

Copper rotor bars give 15–20% lower rotor losses than aluminium, because copper has about 60% higher electrical conductivity. This translates directly to higher motor efficiency. The challenge is that copper melts at 1085°C compared to aluminium's 660°C, so die casting copper requires special tooling and higher energy. Copper rotors are used where efficiency matters more than cost — premium industrial motors (IE3 and IE4 class), some EV motors, and applications where the motor runs continuously (like HVAC compressors).

Winding Types: Copper Winding vs Aluminium Winding

The stator windings also come in two materials:

Copper winding is the standard for most quality motors. Copper has lower resistance, so the motor runs cooler and more efficiently. It is also easier to wind and solder.

Aluminium winding is used in cost-sensitive applications. In India, many mixer grinder motors and economy ceiling fans use aluminium stator windings to bring down the price. The trade-off is slightly higher resistance, more heat, and lower efficiency. If you have used a mixer grinder that heats up quickly during extended grinding, chances are it has aluminium windings.

Lamination Requirements

Induction motor laminations are stamped from CRNO (Cold Rolled Non-Oriented) silicon steel or plain CRCA (Cold Rolled Close Annealed) steel. The stator lamination has slots around its inner diameter for the windings. The rotor lamination has slots for the squirrel cage bars. Both are stamped together in progressive dies, stacked, and welded or interlocked to form cores. For economy applications like mixer grinders, 0.5mm CRCA (CR2 grade to IS 513) is common. For higher efficiency motors, thinner CRNO grades like 50C600, 50C400, or 50C330 are used — the thinner the sheet and the lower the core loss number, the more efficient the motor.

Where Induction Motors Are Used

Ceiling fans, table fans, pedestal fans, wall fans, mixer grinders, washing machines, pumps, compressors, conveyor drives, CNC spindle motors, and practically every factory in India. The single-phase induction motor dominates home appliances. The three-phase version runs industrial machinery.

2. Universal Motors — High Speed from AC or DC

The universal motor is a special type that works on both AC and DC power. It is actually a series-wound DC motor, but its construction allows it to run on AC as well.

Construction

Unlike the induction motor's squirrel cage, the universal motor has a wound rotor (called an armature) with a commutator. Carbon brushes press against the commutator to feed current into the armature. The stator has field windings (not permanent magnets) connected in series with the armature.

Armature Laminations

The armature lamination is the rotor lamination in a universal motor. It has slots around its outer diameter for the armature windings and a central hole for the shaft. These laminations are stamped from CRCA or CRNO steel, stacked with a slight skew (to reduce noise), and pressed onto the shaft. The stator lamination (field lamination) has larger slots for the field coils.

Where Universal Motors Are Used

Mixer grinders, hand blenders, vacuum cleaners, angle grinders, drills, and power tools. Any application where you need very high speed (10,000 to 30,000 RPM) in a compact package. The mixer grinder in your kitchen is almost certainly a universal motor — it is the reason the mixer can spin the blade fast enough to grind spices.

3. Permanent Magnet DC (PMDC) Motors

A PMDC motor is like a universal motor, but instead of field windings on the stator, it uses permanent magnets. This simplifies the construction — no field coils, no field lamination — but the rotor still has an armature with a commutator and brushes.

Ferrous Magnets vs Rare Earth Magnets

The type of permanent magnet used makes a huge difference in performance:

Ferrite (ferrous) magnets are cheap, widely available, and easy to manufacture. They produce a moderate magnetic field. Ferrite magnets are the standard choice for automobile starter motors, windshield wiper motors, power window motors, and door lock motors. In India, almost every two-wheeler and four-wheeler starter motor uses a PMDC design with ferrite magnets. The performance is adequate for short-duration, high-torque applications.

Rare earth magnets (Neodymium Iron Boron — NdFeB, or Samarium Cobalt — SmCo) produce 5–10 times stronger magnetic fields than ferrite in the same volume. This means you can make a much smaller, lighter motor with the same power output. The trade-off is cost — rare earth magnets can be 10–20 times more expensive than ferrite. They are used in applications where size, weight, and efficiency are critical: defence equipment, aerospace actuators, surgical robots, industrial robots, servo motors, and precision instruments.

Armature Laminations for PMDC Motors

Since the stator is just a magnet housing (no lamination needed), only the armature (rotor) needs laminations. These are stamped from CRNO or CRCA steel, with slots for the armature windings and a central bore for the shaft. The laminations are typically skewed during stacking to reduce cogging torque and noise.

4. Brushless DC (BLDC) Motors — The Efficiency Revolution

The BLDC motor is, in many ways, a PMDC motor turned inside out. Instead of magnets on the stator and windings on the rotor, a BLDC motor has windings on the stator and permanent magnets on the rotor. This eliminates the commutator and brushes entirely — hence "brushless."

Why BLDC Is Taking Over

BLDC motors typically achieve 85–92% efficiency compared to 60–75% for comparable induction motors. With no brushes to wear out, they last longer. With no rotor losses (because magnets do not dissipate energy the way rotor windings do), they run cooler. Electronic commutation (using a controller and Hall sensors or back-EMF detection) gives precise speed control.

India's BEE star rating program has been a major driver. When the government mandated higher efficiency standards for ceiling fans, the industry had to move from induction motors to BLDC motors. A BLDC ceiling fan draws 28–35 watts compared to 70–80 watts for a conventional induction fan. The same shift is happening in pumps, refrigerator compressors, washing machine drives, and air conditioner blower motors.

Inner Rotor vs Outer Rotor

Inner rotor BLDC: The rotor (with magnets) sits inside the stator. This is the standard configuration for most industrial BLDC motors, EV hub motors, and pump motors. The rotor is smaller, so it has lower inertia and can accelerate faster.

Outer rotor BLDC: The rotor (with magnets on its inner surface) surrounds the stator. The stator is the stationary inner part. This design is common in ceiling fans and computer cooling fans, where the outer rotor directly drives the blade or impeller without a separate shaft coupling.

Stator and Rotor Laminations for BLDC Motors

BLDC stator laminations have concentrated winding slots — typically fewer, wider slots compared to an induction motor stator. Common configurations are 9 slots/6 poles, 12 slots/8 poles, 12 slots/14 poles, and so on. The rotor lamination has pockets for the permanent magnets — either surface-mounted or interior (IPM — Interior Permanent Magnet). IPM designs are preferred for high-speed applications because the magnets are protected from centrifugal forces. The lamination material is CRNO silicon steel, typically 50C600 to 50C330 grade for good efficiency. For high-performance BLDC motors in EVs, thinner grades (0.2–0.35mm) with lower core losses are specified.

5. Permanent Magnet Synchronous Motors (PMSM)

A PMSM is closely related to a BLDC motor — both have permanent magnets on the rotor and windings on the stator. The key difference is in the back-EMF waveform and control strategy. BLDC motors have a trapezoidal back-EMF and are driven by square-wave (six-step) commutation. PMSM motors have a sinusoidal back-EMF and are driven by sinusoidal (FOC — Field Oriented Control) commutation.

Why PMSM Matters for EVs and Industry

PMSM motors deliver smoother torque with less vibration and noise. They achieve higher efficiency at partial loads. Most modern EV traction motors — in cars, buses, and two-wheelers — are IPM-PMSM types. Tesla's Model 3, Tata Nexon EV, and Ather 450X all use some variant of PMSM technology.

Non-Magnetic PMSM — An Emerging Concept

Researchers are experimenting with PMSM designs that reduce or eliminate rare earth magnets. Some approaches use a combination of reluctance torque and a smaller quantity of magnets (called PMa-SynRM — Permanent Magnet Assisted Synchronous Reluctance Motor). Others use ferrite magnets with clever rotor geometry to match the performance of rare earth designs. This is driven by the cost and supply-chain risk of rare earth materials, which are largely controlled by China.

Lamination Requirements

PMSM laminations are similar to BLDC laminations but often demand tighter tolerances. The rotor laminations have precisely shaped magnet pockets, flux barriers, and bridges that must be stamped with minimal burr. The stator slots are designed for distributed windings (unlike BLDC's concentrated windings). Material is typically thin CRNO — 0.2mm to 0.35mm — with very low core loss grades (35C250 to 50C400) to handle the high electrical frequencies in EV traction motors running at 10,000–15,000 RPM.

6. Switched Reluctance Motors (SRM)

The SRM is the simplest motor in terms of rotor construction. The rotor has no magnets, no windings, no bars — it is just a stack of laminations with salient poles (projections). The torque is produced by the rotor's tendency to align itself with the energised stator poles (reluctance torque).

Advantages

SRMs are extremely rugged and cheap to build. The rotor is just a shaped piece of steel — no copper, no magnets, no die casting. They tolerate high temperatures because there is nothing on the rotor that can demagnetise or melt. They are used in some mining equipment, textile machines, and experimental EV designs.

Challenges

SRMs produce significant torque ripple and acoustic noise. They need sophisticated electronic controllers. The power density is lower than BLDC or PMSM motors of the same size.

Laminations

Both stator and rotor laminations are stamped from silicon steel. The rotor lamination is a simple shape — just poles projecting outward from a central hub. The stator lamination has poles pointing inward, with concentrated windings on each pole.

7. Axial Flux Motors — The Future of Compact Design

Most motors we have discussed so far are "radial flux" motors — the magnetic flux flows radially (outward from the centre). In an axial flux motor, the flux flows along the shaft axis — parallel to it, not perpendicular.

Construction

Instead of cylindrical stator and rotor cores, an axial flux motor uses flat, disc-shaped stator and rotor assemblies facing each other. The magnets sit on a flat rotor disc, and the stator coils are arranged on a flat disc opposite to it. Some designs have two rotors sandwiching one stator (dual-rotor), or two stators sandwiching one rotor.

Why Axial Flux Is Gaining Attention

Axial flux motors are significantly shorter and more compact than radial flux motors of the same power. They have a higher torque-to-weight ratio. Companies like YASA (now owned by Mercedes-Benz) and Magnax have demonstrated axial flux motors for EV drivetrains, drones, and aircraft propulsion. In India, several EV startups are evaluating axial flux designs for in-wheel motors.

Lamination Challenges

Traditional stamping produces ring or disc-shaped laminations, which wastes a lot of material when making axial flux stator cores. Some manufacturers use segmented stator cores — individual tooth segments that are stamped separately and assembled into a ring. Others use soft magnetic composites (SMC) or wound strip cores instead of stamped laminations. The rotor in most axial flux designs does not need laminations — it is just a disc with magnets.

8. Stepper Motors

Stepper motors are designed for precise position control rather than continuous rotation. They move in discrete "steps" — typically 1.8° per step (200 steps per revolution). They are used in 3D printers, CNC machines, textile machines, ATM currency dispensers, and medical equipment.

Construction

The stator has multiple poles with concentrated windings. The rotor has teeth (in a variable reluctance type) or a permanent magnet (in a PM stepper) or both (hybrid stepper). The hybrid stepper is the most common — it combines a permanent magnet with fine-toothed rotor laminations for high resolution.

Laminations

Stepper motor laminations have very fine teeth — often 50 teeth on a small rotor. The stamping needs to be extremely precise, with tight slot-width tolerances and minimal burr. The material is typically 0.35mm or 0.5mm silicon steel.

9. Servo Motors

Servo motors are high-performance motors designed for precise control of position, speed, and torque. Most modern servo motors are PMSM or BLDC types with high-resolution encoders (optical or magnetic) mounted on the shaft.

Applications

Industrial robots (each joint has a servo motor), CNC machine tool spindles and feed axes, packaging machines, semiconductor manufacturing equipment, and defence systems (gun turrets, missile fin actuators, radar antenna drives).

Why Defence and Aerospace Prefer Rare Earth Magnets

In defence and space applications, the motor must deliver maximum power in minimum volume and weight. A servo motor for a missile fin actuator might need to deliver 5 Nm of torque in a 50mm diameter package, operating at -40°C to +150°C. Only rare earth magnets (NdFeB or SmCo) can produce the magnetic field density needed for this. SmCo is preferred over NdFeB in extreme temperature applications because it has better thermal stability — it does not demagnetise even at 300°C. The cost premium is justified because failure in a defence system is not an option.

10. Drone Motors — A Special Case

Drone motors are essentially small, high-speed BLDC motors optimised for the unique needs of unmanned aerial vehicles. A typical quadcopter drone has four motors, each driving a propeller directly.

Design Requirements

Drone motors need to be extremely light, run at 10,000–30,000 RPM, and have very fast response times for flight stability. Most drone motors use an outer-rotor BLDC design — the rotor bell (with magnets on its inner surface) spins around a fixed stator. This puts the mass at the outside, creating a flywheel effect that smooths out rotation.

Laminations for Drone Motors

Drone motor stator laminations are small — typically 15mm to 40mm outer diameter. They are stamped from thin silicon steel (0.2mm to 0.35mm) to minimise core losses at high electrical frequencies. The slot count is typically 9 or 12 slots with 12 or 14 magnet poles. Because volumes for individual drone designs can be small (a few thousand per year), tooling cost and flexibility matter as much as per-piece cost.

11. Traction Motors for EVs — Where Everything Comes Together

The traction motor is the main drive motor in an electric vehicle — car, bus, truck, two-wheeler, or three-wheeler. It converts electrical energy from the battery into mechanical torque at the wheels.

Types Used in EV Traction

Most EV traction motors today are IPM-PMSM (Interior Permanent Magnet — Permanent Magnet Synchronous Motor). Some use induction motors (Tesla Model S and X originally used induction; the Model 3 and later switched to PMSM). A few use SRM (switched reluctance). The trend globally is towards PMSM for its superior efficiency and power density.

Lamination Requirements

EV traction motor laminations are among the most demanding applications for a stamping company. The requirements include thin material (0.2–0.35mm CRNO), tight burr limits (under 0.02mm), precise magnet pockets in the rotor, high stacking factor (97%+), and very low core loss grades (35C250 to 50C400). The outer diameters can range from 150mm for a two-wheeler motor to 250mm+ for a car motor. Production volumes for successful EV models can reach millions per year.

Summary: Motor Types at a Glance

What Does This Mean for Laminations?

Every motor type listed above needs stamped laminations — whether it is a stator lamination, a rotor lamination, or an armature lamination. The material, thickness, slot geometry, and tolerances change with the motor type, but the fundamental need remains: precision-stamped silicon steel or CRCA laminations, stacked and assembled into cores.

At SNV Stamping Solutions, we stamp stator and rotor laminations for all these motor types at our ISO 9001:2015 certified plant in Bengaluru. Our 220-ton Yadon high-speed press line with Yaskawa servo feeding handles CRNO silicon steel from 0.2mm to 1.0mm thickness and up to 400mm strip width. Whether you need laminations for a BLDC ceiling fan, an EV hub motor, a mixer grinder armature, a drone motor, or an industrial servo — we stamp to your drawing and deliver stacked or welded cores, ready for winding.

Send us your lamination drawing and annual volume at sales@snvstampings.com or call +91 9980668620.

Frequently Asked Questions

What are the main types of electric motors?

The main types are AC Induction Motors (single-phase and three-phase), Permanent Magnet DC (PMDC) Motors, Brushless DC (BLDC) Motors, Switched Reluctance Motors (SRM), Permanent Magnet Synchronous Motors (PMSM), and advanced designs like Axial Flux Motors. Each uses different rotor, stator, and magnet configurations suited to specific applications.

What is the difference between copper rotor and aluminium rotor in induction motors?

Copper rotors offer 15–20% lower rotor losses and higher efficiency because copper has better electrical conductivity. However, copper die casting is harder and more expensive. Aluminium rotors are cheaper, lighter, and easier to cast, making them dominant in cost-sensitive applications like mixer grinders and economy fans.

Why are BLDC motors replacing induction motors?

BLDC motors offer 85–92% efficiency versus 60–75% for induction motors. They have no rotor losses, deliver better speed control, produce less heat, and last longer. Energy efficiency norms (BEE star ratings, IE3/IE4 standards) are pushing the shift across fans, pumps, appliances, and EVs.

What kind of laminations do different motor types need?

Induction motors need stator and squirrel-cage rotor laminations. BLDC and PMSM motors need stator laminations with concentrated or distributed winding slots and rotor laminations with magnet pockets. Universal motors need stator field laminations and armature laminations. EV traction motors need thin (0.2–0.35mm) low-loss silicon steel laminations.

What is an axial flux motor?

In a conventional radial flux motor, the magnetic flux flows radially outward. In an axial flux motor, the flux flows along the shaft axis. This makes axial flux motors flatter and more compact — ideal for drones, EVs, and robots. They use disc-shaped laminations instead of cylindrical ones.