Traction Motor Lamination Manufacturer in India

Traction Motors: The Heart of Every Electric Vehicle

Every electric vehicle on the road — from 2-wheeler scooters and 3-wheeler autos to passenger cars and city buses — depends on a traction motor to convert electrical energy into motion. The traction motor is the primary drive motor. It replaces the internal combustion engine entirely in battery electric vehicles (BEVs) and works alongside it in hybrid electric vehicles (HEVs).

India's EV market is growing rapidly. With government policies such as FAME II and state-level EV subsidies, manufacturers across the country are scaling up production of electric 2-wheelers, 3-wheelers, passenger cars, and buses. This growth is driving strong demand for high-quality traction motor laminations — the stamped silicon steel cores that form the magnetic circuit of these motors.

SNV Stamping Solutions Pvt Ltd is an emerging manufacturer of traction motor laminations based in Bengaluru. Our facility is equipped with a Yadon 220T high-speed press with Yaskawa servo feeder, set up specifically for precision stamping of motor laminations in thin-gauge CRNO silicon steel.

What Makes Traction Motor Lamination Stamping Different?

Traction motor laminations have tighter requirements than laminations for industrial motors or home appliance motors. Here is why:

Thin Gauge for Low Core Loss

Traction motors operate at high rotational speeds and high electrical frequencies — often 400 Hz and above, compared to 50 Hz in a standard industrial motor. At these frequencies, eddy current losses increase sharply with lamination thickness. That is why EV traction motors typically use 0.2mm to 0.35mm thick silicon steel, much thinner than the 0.5mm commonly used in industrial motors.

Stamping thin-gauge material demands precise press control. The Yadon 220T at our facility features a double-plunger press design that delivers consistent stroke accuracy even at high speeds, making it well-suited for thin-gauge traction motor lamination stamping.

Tight Dimensional Tolerances

Traction motors are compact and operate at high speeds. The air gap between stator and rotor is kept very small — sometimes as low as 0.5mm — to maximise magnetic flux and motor efficiency. This means the lamination dimensions must be accurate and consistent. Any variation in inner diameter (stator bore) or outer diameter (rotor) will affect the air gap uniformity, leading to unbalanced magnetic pull, vibration, and noise.

Low Burr Height

Burr on the stamped edges of laminations creates problems in two ways: it reduces the effective stacking factor (meaning fewer laminations fit in a given stack height), and it can cause short circuits between adjacent laminations, increasing eddy current losses. For traction motor applications, burr height must be controlled below 0.03mm, and ideally below 0.02mm.

High Stacking Factor

The stacking factor — the ratio of actual steel in a core stack to the total stack height — directly affects motor performance. A higher stacking factor means more magnetic material per unit length, which improves torque density. Traction motor cores typically require a stacking factor of 95% or higher. At SNV, we consistently achieve 97-98% stacking factor through tight burr control and in-die auto stacking.

IPM Rotor and Stator Laminations for Traction Motors

Most modern EV traction motors use the Interior Permanent Magnet (IPM) motor design. This design offers a good balance of torque density, efficiency, and field-weakening capability — all important for vehicle applications.

IPM Rotor Laminations

IPM rotor laminations have precisely shaped slots or pockets where permanent magnets are inserted after the core is assembled. The geometry of these magnet slots is critical — it determines the magnetic flux path, the reluctance torque contribution, and the mechanical strength of the rotor at high speeds.

Key requirements for IPM rotor laminations:

• Accurate slot dimensions for proper magnet fit and retention
• Thin bridges between slots and rotor OD for magnetic performance, while maintaining mechanical strength
• Consistent OD for uniform air gap
• Low core loss material (grades such as 50C470 or lower) to minimise rotor iron losses
• Auto skewing during stacking to reduce cogging torque and torque ripple

Stator Laminations

Traction motor stator laminations feature slots for the copper winding. The slot geometry affects the winding fill factor, the slot leakage inductance, and the thermal performance of the motor. Common configurations include distributed winding (for smoother torque) and concentrated winding (for simpler manufacturing).

Key requirements for stator laminations:

• Accurate slot dimensions and positioning for proper winding insertion
• Consistent bore diameter for uniform air gap
• Good surface insulation between laminations to prevent inter-lamination shorts
• Tight OD tolerance for press-fit into the motor housing

Material and Quality Specifications

SNV Stamping Solutions works with CRNO (Cold Rolled Non-Oriented) silicon steel across a range of grades suited to different traction motor performance requirements.

Parameter	Specification
Material	CRNO Silicon Steel
Grades	50C1300, 50C800, 50C600, 50C470, 50C330
Thickness Range	0.2mm to 1.0mm
Max Strip Width	400mm
Burr Height	Within 0.02mm
Stacking Factor	97-98%
Stacking	In-die auto stacking with auto skewing
Stack Height Control	Separate cams for stator and rotor stack heights
Certification	ISO 9001:2015

For traction motor applications, we recommend grades 50C470 or lower (such as 50C330) in 0.2mm to 0.35mm thickness. These grades offer low core loss at high frequencies, which directly translates to better motor efficiency and longer vehicle range.

Manufacturing Capabilities

High-Speed Press

Our Yadon 220T high-speed press with double-plunger design provides the tonnage and precision needed for traction motor lamination stamping. The double-plunger configuration ensures that the press force is evenly distributed across the die, reducing deflection and maintaining dimensional accuracy — especially important when stamping thin-gauge material.

Servo Feeder

The Yaskawa servo feeder ensures accurate and consistent strip feed, which is critical for maintaining pitch accuracy across the lamination profile. It handles strip widths up to 400mm and thicknesses from 0.2mm to 1.0mm, with the decoiler and straightener line feeding material smoothly into the press.

CNC Turning for Rotor Shafts

In addition to lamination stamping, SNV offers CNC turning for rotor shafts on our Ace Designers Super Jobber 500 LM lathe. This machine delivers 10-15 micron accuracy, suitable for the shaft tolerances required in traction motor rotor assemblies. Having lamination stamping and shaft machining under one roof simplifies the supply chain for motor manufacturers.

Quality Infrastructure

SNV Stamping Solutions is ISO 9001:2015 certified. Our quality process includes incoming material inspection, in-process dimensional checks, burr measurement, and stacking factor verification. Every batch of traction motor laminations is inspected to ensure it meets the agreed specifications before dispatch.