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Magnetic Slot Wedges

Magnetic Slot Wedges Manufacturer in India Epoxy Magnetic Wedge

Harnawa Inc. manufactures magnetic slot wedges — epoxy magnetic wedge & magnetic conductive wedge for high efficiency motors. Class B/F/H. Pan-India supply.
Magnetic Slot Wedges | Epoxy Glass Fabric Magnetic-Conductive Insulation

Magnetic Slot Wedge Manufacturer in India

Every slot wedge does not only act as an insulator. The magnetic slot wedge is the highly specialized form of the regular slot wedge which performs the dual purpose in the motor; one to secure the winding coil physically and another to design the magnetic circuit of the motor in such a manner that will increase efficiency.

As an expert manufacturer of magnetic slot wedges in India, Harnawa Inc. provides the high precision made epoxy based magnetic wedge parts for motors aiming at improved efficiency, all of which are internationally certified and delivered throughout India out of our manufacturing facility located in Mumbai, as a part of our services as the established manufacturer of Electrical Insulation Materials in India.

How a Magnetic Slot Wedge Differs From a Standard Wedge

The regular slot wedge is purely meant to serve as an insulator and mechanical support device since its sole purpose is to close off the slot and hold the coil in place. The magnetic conductive wedge, on the other hand, is purposely designed to have magnetic conductive qualities inherently incorporated into the laminate construction of the wedge. This makes the wedge part of the motor magnetic circuit, thus ensuring that the air-gap flux is well distributed at the slot opening without the usual harmonics losses found in ordinary non-magnetic wedges.

It is for this reason that motors designed with magnetic slot wedges exhibit lesser cogging torque, fewer harmonics losses, and increased efficiency than those with regular insulating wedges, hence their increasing application in efficient motor wedge designs.

Structure & Materials

The magnetic slot wedges used in Harnawa Inc. are made using E-Glass fabric along with epoxy resin, which together form an epoxy glass fabric magnetic-conductive laminate. Such a laminate performs two different roles:

  • The mechanical strength, dimensional stability and dielectric properties of the E-glass fabric + epoxy resin composition make it a natural fit for a slot component
  • The composite material makes possible active influence on the flux path of the motor by the wedge, rather than a simple passivation of the slot opening with an insulating layer

This dual-function design is what separates a true magnetic wedge from a standard epoxy slot wedge finished in a similar form factor.

Insulation Class Coverage — Class B / F / H

Harnawa Inc.’s magnetic slot wedges can be used in motors that have insulation classes of either B, F, or H. In other words, the motor designer has flexibility in selecting the magnetic slot wedge depending on the heat resistance of the motor’s application, ranging from Class B to H, including EV traction motors.

Function — More Than Just Retention

The core function of a magnetic slot wedge is best understood as two jobs in one component:

Optimization of Magnetic Circuit – The magnetic circuit can be optimized because of the magnetic circuit offered by the magnetic slot wedge for the slot opening and minimizing flux leakage and harmonic distortion.

Securing of Coil Winding – Similarly, the magnetic slot wedge holds the coil windings within the slot just like the standard slot wedge through mechanical means to avoid movement of the windings due to vibration, electromagnetic forces, and centrifugal force.

Customization

Each magnetic slot wedge is customized according to your needs when it comes to size, material, and thickness of the magnetic slot wedge. This is because the efficiency of a magnetic wedge depends on geometry and magnetic conductive materials used.

Where Magnetic Slot Wedges Are Used

  • High-efficiency industrial motors – IE3/IE4-rated motors where each efficiency percentage point is critical
  • EV drive motors – where efficiency improvements have direct impacts on range and heat management
  • Premium efficiency generators – improving efficiency by minimizing harmonic losses from generator winding assembly
  • Applications requiring precision control of motors – where cogging torque minimization helps in improving control and precision

Completing the Motor Insulation System

A magnetic slot wedge is typically specified alongside the same family of insulation materials used with standard slot wedges, ensuring compatibility across the full winding assembly:

Sourcing the magnetic slot wedge alongside these complementary materials from a single certified supplier keeps quality consistent across the entire winding insulation system.

Certifications & Quality Assurance

All magnetic slot wedges sold by Harnawa Inc. are produced and tested in line with international quality standards, which include:

  • UL certification
  • Compliance with CE marking
  • Compliance with RoHS
  • Manufacturing that complies with ISO 9001:2015
  • Compliance with

Magnetic Slot Wedge Manufacturer in India — Why Choose Harnawa Inc.

Harnawa Inc. is a leading supplier of magnetized slot wedges in India, which manufactures epoxy magnetized wedges specifically made for motor manufacturers who want to achieve actual efficiency levels — along with all kinds of electrical insulation materials used in the manufacture of motors, generators, transformers, and switchgears.

What sets us apart:

  • Custom-made epoxy fiberglass magnetic-conductive laminate design
  • Single product range with Class B/F/H insulation
  • Designed specifically for the coil-holding and magnetic circuitry aspects
  • Can be customized in terms of size, material, and thickness as per motor design
  • Wide Pan India distribution across Mumbai, Delhi, Pune, Ahmedabad, and elsewhere
  • Quality management systems certified (UL, CE, RoHS, ISO 9001:2015, REACH)

Frequently Asked Questions

1.What is the use of magnetic slot wedge?

Magnetic slot wedges hold winding turns of motor within the slots while also providing an optimal magnetic circuit through the slot openings which reduces harmonic losses.

2.How does a magnetic conductive wedge differ from an ordinary epoxy slot wedge?

An ordinary slot wedge is only a mechanical and insulating one while the magnetic conductive wedge has special magnetic-conducting features which form part of flux path of motor and increase its efficiency.

3.What kinds of insulation classes do magnetic slot wedges come in?

Harnawa Inc. provides magnetic slot wedges in class B, class F and class H insulation classes.

4.Do magnetic slot wedges increase motor efficiency?

Yes, magnetic slot wedges reduce flux losses and harmonics within the slot opening thereby increasing motor efficiency.

5.Can magnetic slot wedge be custom made with respect to its size and base material?

Yes, the size, base material and thickness are all customizable.

Products image

Available Material Options
Material Grade Description
FR4 Glass epoxy laminate suitable for general electrical insulation applications
G11 High-temperature glass epoxy laminate designed for elevated thermal performance
3240 Epoxy phenolic cotton cloth laminate offering good mechanical strength and machinability
GPO-3 Polyester glass mat laminate with excellent arc resistance and flame retardancy
EPGC308 High-strength epoxy glass cloth laminate for demanding electrical and mechanical conditions
Magnetic Slot Wedge Loss-reducing magnetic composite designed to improve motor efficiency

Each material is selected based on thermal class, voltage level, mechanical stress, and overall efficiency requirements.

Product Name

Magnetic Slot Wedge

Product Type

Motor Slot Insulation & Retention Component

Base Materials

E-glass fabric + Epoxy resin

Structure

Epoxy glass fabric magnetic-conductive laminate

Insulation Class

Class B / F / H

Function

Magnetic circuit optimization & coil retention

Customization

Size, material, thickness as per motor design

NEMA, IEC, Mil Spec Material Comparative Table
NEMA IEC Mil Spec Resin Substrate
NEMA G-10EPGC 201, 21*MIL-I-24768/2 GEEEpoxyGlass Cloth
NEMA FR4EPGC 202, 23*MIL-I-24768/27 GEE-FEpoxyGlass Cloth
NEMA G-11EPGC 203, 22*MIL-I-24768/3 GEBEpoxyGlass Cloth
NEMA FR5EPGC 204MIL-I-24768/28 GEB-FEpoxyGlass Cloth
EPGC 205EpoxyGlass Cloth
EPGC 306EpoxyGlass Cloth
EPGC 307EpoxyGlass Cloth
EPGC 308EpoxyGlass Cloth
EPGC 309EpoxyGlass Cloth
EPGC 310EpoxyGlass Cloth
EPGC 311EpoxyGlass Cloth
EPGM 203EpoxyGlass Mat
EPPC 301EpoxyPolyester Cloth
NEMA G-5MFGC 201, 20*MIL-I-24768/8 GMGMelamineGlass Cloth
NEMA G-9MFGC 201MIL-I-24768/1 GMEMelamineGlass Cloth
NEMA CPFCC 201, 23*MIL-I-24768/16 PBMPhenolicCotton Cloth
NEMA CEPFCC 202, 22*MIL-I-24768/14 FBGPhenolicCotton Cloth
NEMA LPFCC 203MIL-I-24768/15 FBIPhenolicCotton Cloth
NEMA LEPFCC 204, 21*, 24*MIL-I-24768/13 FBEPhenolicCotton Cloth
NEMA XPFCP 201, 21*MIL-I-24768/12 PBMPhenolicCellulosic Paper
NEMA XPPFCP 201MIL-I-24768/19 PBM-PPhenolicCellulosic Paper
NEMA XXXPFCP 204MIL-I-24768/10 PBEPhenolicCellulosic Paper
NEMA XXPFCP 202, 23*MIL-I-24768/11 PBGPhenolicCellulosic Paper
NEMA XXPPFCP 203MIL-I-24768/21 PBG-PPhenolicCellulosic Paper
NEMA XXXPPFCP 204MIL-I-24768/22 PBE-PPhenolicCellulosic Paper
NEMA XPCPFCP 207MIL-I-24768/20 PBM-CPhenolicCellulosic Paper
NEMA G-3PFGC 201, 21*MIL-I-24768/18 GPGPhenolicGlass Cloth
NEMA GPO-1UPGM 201MIL-I-24768/4PolyesterGlass Mat
NEMA GPO-2UPGM 202MIL-I-24768/5PolyesterGlass Mat
NEMA GPO-3UPGM 203MIL-I-24768/6PolyesterGlass Mat
UPGM 205PolyesterGlass Mat
PIGC 301PolyimideGlass Cloth
NEMA G-7SIGC 201, 21*MIL-I-24768/17 GSGSiliconeGlass Cloth
Note:
1 – Comparable grades can vary slightly in specification based on test methods and thickness.
* Indicates IEC tube standard.

Applications of our Products

Main Application Areas
  • Industrial Motors – Slot insulation for pumps, fans, and compressors
  • New Energy Vehicles (EVs) – Rotor slot wedges for traction motors
  • Wind Turbines – Stator slot fixation in large generators
  • High-Efficiency Motors (IE4 / IE5) – Magnetic slot wedges for loss reduction
  • High-Voltage Motors – GPO-3 and EPGC308 for enhanced insulation safety
Material Selection Guide
  • FR4 / G11 – Recommended for standard industrial motor applications
  • GPO-3 / EPGC308 – Suitable for high-voltage or humid operating environments
  • Magnetic Slot Wedge – Ideal for energy-efficient and premium motor designs
Applications - PVC coated fiberglass sleeve

Key Features

Excellent Electrical Insulation

Superior Thermal Resistance

High-performance Protection

Industries We Serve

Explore the Wide Range of Industries We Proudly Serve

Providing reliable and high-performance insulation solutions across various sectors.
Certification

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Certifications

ISO 9001:2015
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REACH Compliant
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Electrical Research
and Development
Association
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Inquiries and Custom Solutions

Find your right electrical insulation materials with us!

You have questions according to our insulating or want to send an inquiry? Our sales representative will be happy to help you.
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