What is Electric Motor Laminations?

author: Zove

2026-10-10

Reenives: Electric Motor Laminations supplier. Custom stator cores, free samples, global shipping.

What Are Electric Motor Laminations? A Complete Engineering Guide for UAV and Brushless Motor Manufacturers

Your motor passes bench testing with acceptable efficiency, but at 6,000 RPM under continuous load the stator housing climbs past 90°C. Field returns show insulation breakdown at 200 hours instead of the expected 2,000. When failure analysis is completed, the verdict points back to the same place: the Electric Motor Laminations were not specified, stacked, or insulated to the standard the application demands.

Laminations are the thin electrical steel sheets that make up the stator and rotor cores of every brushless motor. Individually they look like simple stamped plates. Collectively they determine how much eddy current loss the motor generates, how uniformly the air gap is maintained, and how long the insulation system survives under thermal cycling. If you source laminations on thickness and price alone, you are accepting hidden losses that only appear in the field.

This guide explains electric motor laminations from the inside out: definition, classification, key parameters with test data, UAV application requirements, and a practical selection workflow. It is written for procurement managers and R&D engineers who need verifiable facts, not marketing copy.

What Are Electric Motor Laminations?
Electric Motor Laminations Classification
Key Lamination Parameters & Test Data
Application Scenarios & Lamination Requirements
Electric Motor Laminations Selection Steps
FAQ: Lamination Parameters Engineers Ask About
Summary & Get in Touch
About Dongguan Runlu Motor Technology Co., Ltd.

What Are Electric Motor Laminations?

Electric Motor Laminations are thin sheets of electrical steel — typically 0.10mm to 0.65mm thick — that are stamped, stacked, and bonded into the magnetic cores of electric motors. Each sheet carries a thin insulating coating on both faces to prevent current from circulating between layers. When stacked, the laminations form the stator core (stationary) and rotor core (rotating) that guide magnetic flux through the motor.

The reason motors use stacked laminations instead of solid steel is fundamental physics. A solid steel core would allow large eddy currents to circulate inside the metal as the magnetic field alternates. Those eddy currents produce heat and waste energy without contributing to torque. By slicing the core into insulated laminations, the circulating paths are broken, and eddy current loss drops dramatically. The thinner the lamination, the greater the loss reduction.

Each lamination performs three critical functions in a brushless motor:

Guides magnetic flux between the rotor magnets and the stator windings
Holds the winding slots in precise geometric relationship to the rotor
Dissipates heat generated by copper loss and core loss

In a typical 14-pole drone motor spinning at 6,000 RPM, the magnetic field inside the stator reverses direction hundreds of times per second. At this frequency, lamination thickness, material grade, burr height, and stacking pressure directly determine whether the motor runs cool and efficient or overheats and loses thrust.

Electric Motor Laminations Stamped Electrical Steel Stack - Reenives Drone Electric Motor Laminations Supplier

Precision-stamped electric motor laminations for drone stator and rotor cores. Source: Reenives

Electric Motor Laminations Classification

Electric motor laminations are classified by material grade, lamination thickness, and the core geometry they are stamped to produce. The table below maps the main categories to their characteristics and typical motor applications.

Classification	Typical Thickness	Core Loss (50Hz/1.5T)	Typical Motor
Standard Non-Oriented Silicon Steel	0.50mm / 0.35mm	≤ 3.0 W/kg	Cost-sensitive consumer motors
High-Grade Non-Oriented Silicon Steel	0.35mm / 0.20mm	≤ 1.5 W/kg	Industrial UAV, robotics, servo motors
Ultra-Thin High-Frequency Steel	0.20mm / 0.10mm	≤ 1.0 W/kg	High-KV FPV motors, high-frequency BLDC
Amorphous Alloy Laminations	0.025mm–0.05mm	≤ 0.5 W/kg	Extreme-efficiency, specialty high-frequency motors

Engineering note: Industrial multi-rotor UAVs commonly use high-grade 0.20mm laminations with C5 or C6 insulation coating. The thinner the lamination, the greater the stamping precision required — burr height and interlocking accuracy must be controlled to keep core loss at the finished stack level close to the raw material value.

Key Lamination Parameters & Test Data

The table below summarizes the parameters most commonly specified when sourcing electric motor laminations, together with the performance characteristic each parameter influences.

Lamination Parameters vs. Motor Performance

Lamination Parameter	Influences	Reference Value
Lamination thickness	Eddy current loss, efficiency, heat	0.20mm for high-performance UAV
Core loss (P1.5/50)	Motor efficiency, thermal rise	≤ 1.5 W/kg for industrial UAV
Concentricity tolerance	Air-gap uniformity, vibration, cogging	< 0.03mm preferred
Burr height	Interlaminar short circuits, hot spots	< 0.02mm for low-loss stacks
Insulation coating class	Interlaminar resistance, temperature rating	C5 / C6 for industrial UAV
Stack height consistency	Torque output, vibration	±0.05mm or tighter
Max flux density	Torque capability under load	≥ 1.9 T for heavy-lift motors

Source: Reenives electric motor lamination specifications and internal lab test data, 2025.

Lamination Thickness vs. Core Loss — Controlled Test Data

Reenives conducted a controlled bench test on a standard 14-pole BLDC motor, keeping all other components constant and swapping only the Electric Motor Laminations from 0.35mm standard silicon steel to 0.2mm low-loss steel.

Parameter	0.35mm Standard Silicon Steel	0.2mm Low-Loss Steel	Delta
Motor efficiency	Baseline	+1–2%	Longer flight time
Core + winding temperature rise	Baseline	−10°C+	Slower insulation aging
Eddy current loss reduction	Baseline	Up to 40% lower	Less heat at high RPM

Data source: Reenives internal lab tests, 2025. Test conditions: standard 14-pole BLDC motor, 6S LiPo, 5,000–7,000 RPM. Actual results may vary depending on motor design and assembly quality.

Lamination Specification Reference

Specification	Standard Range	High-Performance Range
Lamination thickness	0.35mm / 0.50mm	0.20mm / 0.10mm
Core loss	≤ 3.0 W/kg	≤ 1.5 W/kg (50Hz/1.5T)
Concentricity tolerance	±0.05mm	±0.02mm
Insulation coating	C3 / C4	C5 / C6
Burr height	< 0.05mm	< 0.02mm
Stack height tolerance	±0.10mm	±0.05mm or tighter

Source: Reenives electric motor lamination specifications. Tested per IEC 60404-2 for specific core loss at 50 Hz / 1.5 T.

Manufacturing Tolerances That Matter

Two motors can use the exact same 0.2mm low-loss electrical steel and still perform differently on the thrust stand. The finished lamination stack — after punching, stacking, and assembly — determines the actual magnetic performance. Key variables include:

Burr height: Large burrs pierce the interlamination insulating coating, creating local short circuits that increase eddy current loss and cause hot spots.
Punching stress: Mechanical stress near the stator teeth alters local magnetic permeability, increasing hysteresis loss. UAV motor teeth are often narrow, so the affected area represents a significant portion of total tooth width.
Stack height variation: Inconsistent stack height changes the effective magnetic circuit area, reducing torque output and introducing vibration.
Air-gap concentricity: Tight concentricity (<0.03mm) keeps the air gap uniform — critical for torque smoothness and noise reduction.

Application Scenarios & Lamination Requirements

Different mission profiles place different demands on electric motor laminations. The table below maps four common industrial applications to their lamination requirements.

Application	Motor Type	Lamination Priority	Key Metric
Agricultural spraying UAV	Low-KV outrunner (90–120 KV)	Thermal stability, coating durability	Continuous duty at high ambient temp
Industrial inspection UAV	Medium-KV outrunner (100–150 KV)	Concentricity, low vibration	Concentricity < 0.03mm
Logistics / heavy-lift UAV	Low-KV outrunner (< 90 KV)	High flux density capacity	Max flux density ≥ 1.9 T
FPV / surveying UAV	High-KV outrunner (1700–2700 KV)	Eddy current loss minimization	0.2mm or 0.1mm laminations
Robotics / servo BLDC	Inrunner, high pole count	Low cogging torque, tight slot geometry	Concentricity < 0.02mm

Electric Motor Laminations Applications - UAV, Robotics, Industrial BLDC

Electric motor laminations for UAV, robotics, and industrial brushless motor applications. Source: Reenives

For agricultural drones operating in high-temperature environments, the lamination coating must maintain its insulating properties even as ambient temperature approaches the motor's thermal limit. A core loss reduction of even 1% translates to extended operation cycles and slower insulation aging — directly impacting total cost of ownership for fleet operators.

Electric Motor Laminations Selection Steps

The workflow below follows the standard approach used by industrial motor manufacturers. Each step includes the lamination specifications you should verify with your supplier.

Define the motor's operating point.
Establish rated voltage, continuous current, target RPM, and duty cycle. The lamination stack must be sized so that magnetic flux density stays below saturation at the highest expected load.
Select the slot and pole configuration.
Common combinations in UAV motors: 12-slot/14-pole, 18-slot/16-pole, 24-slot/22-pole. Slot-pole combination determines cogging torque, winding factor, and harmonic content — all of which affect noise and vibration.
Choose lamination thickness and material grade.
0.35mm standard silicon steel for cost-sensitive applications; 0.20mm low-loss steel for high-efficiency industrial UAV; 0.10mm for high-frequency or extreme-efficiency designs.
Verify core loss and flux density.
Request core loss data at 50 Hz / 1.5 T for the finished stack. Confirm maximum flux density capability against the motor's peak torque requirement.
Audit manufacturing tolerances.
Ask these specific questions:
- What is the burr height limit on the finished lamination?
- What is the concentricity tolerance between stator inner diameter and rotor outer diameter?
- What insulation coating class is applied? (C3, C4, C5, or C6)
- What is the stack height tolerance?
- Can you provide interlamination resistance test results on the finished stack?
Validate thermal and vibration performance.
Target motor temperature rise below 80°C under continuous duty. For industrial drones, verify that the lamination stack maintains dimensional stability across the full operating temperature range and that the finished motor's vibration signature meets your platform's requirements.

Procurement tip: When evaluating lamination suppliers, request test data from the finished stack, not just the raw material datasheet. Processing stress, burr height, and stacking methods can reduce magnetic performance by 5–15% compared to the material's original specification.

FAQ: Lamination Parameters Engineers Ask About

Q1: Does 0.2mm lamination really make a measurable difference compared to 0.35mm?

Yes. In controlled testing on a standard BLDC motor, replacing 0.35mm standard silicon steel with 0.2mm low-loss steel reduced core and winding temperature by over 10°C and improved overall efficiency by 1–2%. Eddy current loss dropped by up to 40%. The difference becomes more pronounced at higher electrical frequencies — which is exactly the operating range of high-RPM drone motors.

Source: Reenives internal lab test data, 2025. Test conditions: standard 14-pole BLDC motor, 6S LiPo, 5,000–7,000 RPM.

Q2: What core loss value should I specify for electric motor laminations?

For high-performance applications, specify core loss ≤ 1.5 W/kg at 50 Hz / 1.5 T. Standard-grade laminations typically run at ≤ 3.0 W/kg. The lower the core loss at this reference point, the less heat the stator generates at high RPM — directly extending operation time and motor lifespan.

Source: Reenives electric motor lamination specification sheet, measured per IEC 60404-2.

Q3: Why does my motor overheat even though I specified low-loss electrical steel?

Material grade is only one variable. Burrs on the lamination edges can pierce the interlamination insulating coating during stacking, creating local short circuits between layers. This interlaminar short circuit generates additional eddy currents and local hot spots — even if the raw steel has excellent specifications. Ask your supplier for burr height control data and interlamination resistance test results on the finished stack.

Source: Motorneo, "How Core Manufacturing Errors Affect Motor Efficiency," industry analysis.

Q4: What concentricity tolerance is acceptable for electric motor laminations?

For BLDC motors, target concentricity < 0.03mm between the stator inner diameter and rotor outer diameter. Tighter tolerance keeps the air gap uniform, which is critical for torque smoothness and noise reduction. A non-uniform air gap causes uneven magnetic pull, leading to vibration, cogging torque, and accelerated bearing wear. Standard laminations often hold ±0.05mm; high-precision laminations achieve ±0.02mm.

Source: Reenives technical bulletin on lamination precision requirements for brushless motors.

Q5: Can stator and rotor laminations be supplied as a matched pair?

Yes. Matched stator and rotor laminations are produced with imported high-speed stamping lines and epoxy powder coating, engineered as a pair to ensure consistent air gaps and low core loss across the assembly. Supplying matched pairs eliminates the dimensional stack-up errors that occur when stator and rotor laminations come from different production runs.

Source: Reenives stator and rotor matched pair product documentation.

Q6: Are core loss test reports available with shipments?

Yes. Each production batch can include core loss test data measured on the finished lamination stack, not just the raw material mill certificate. This allows engineering teams to verify that the actual magnetic performance matches the design specification before integrating the motor into the end product.

Source: Reenives quality assurance documentation.

Summary: Specify the Laminations, Control the Motor

A brushless motor is only as reliable as its Electric Motor Laminations. Thickness, material grade, burr control, and stacking precision determine whether your motor delivers consistent torque or battles thermal degradation. For industrial motor manufacturers and UAV integrators, the lamination stack is the component that quietly defines the performance ceiling.

The numbers speak for themselves:

0.2mm laminations vs. 0.35mm: +1–2% efficiency, −10°C+ temperature rise
Concentricity < 0.03mm: smoother torque, lower vibration, quieter operation
Core loss ≤ 1.5 W/kg: longer operation time, slower insulation aging

Whether you are qualifying a new motor design or looking to reduce field failures, the conversation should start with the laminations. Reenives Drone Electric Motor Laminations Supplier provides matched stator and rotor cores, custom tooth geometry, and full test documentation for UAV and brushless motor manufacturers worldwide.

Ready to Discuss Your Electric Motor Lamination Requirements?

Website: www.reenives-bldcmotor.com

WhatsApp: +86-13377741885

Email: linda_reenives@163.com

Free samples available for qualified engineering evaluations. Global shipping with complete export qualifications.

Dongguan Runlu Motor Technology Co., Ltd.

Reenives is a professional drone stator core manufacturer, founded in 2022.

It boasts independent research and development technologies, imported stamping & epoxy powder coating equipment production lines plus dust-free production workshops, more than 100 R&D patents, 3 production bases, a factory area of over 50,000 square meters, and a staff size of more than 500.

From production to sales, we support bulk purchasing, private mould development, and sample making, and can provide tailor-made perfect solutions for your production and usage scenarios.

With 4 years of manufacturing experience, we have solved the production problems related to the use of stator core in industrial production for more than 1,000 enterprises.

We can ship globally (with complete export qualifications). Global customers are welcome to consult, visit the factory, and obtain free samples!

© 2026 Dongguan Runlu Motor Technology Co., Ltd. (Reenives). All rights reserved. Electric Motor Laminations manufacturer serving the UAV, robotics, and brushless motor industries worldwide. Search for "Reenives Drone Electric Motor Laminations Supplier" to learn more.