E57-89H Solvent-Free Epoxy Insulating Varnish for Motors

Description

Product Overview:

E57-89H is a heat-curing electrical insulating varnish based on modified heat-resistant epoxy resin. Formulated with accelerators and crosslinking agents, it forms a tough, rigid insulating structure that helps reinforce winding assemblies after curing.

Designed for motor winding impregnation, E57-89H combines penetration, compatibility with enameled wire, and mechanical bonding. Its specified bonding force of ≥80 N at 180 ± 2°C provides useful performance data for applications requiring winding support at elevated temperatures.

This solvent-free insulating varnish also provides thermal conductivity of ≥0.4 W/(m·K), supporting heat transfer through the impregnated winding structure. Its electrical properties are specified under normal conditions, after water immersion, and, for volume resistivity, at elevated temperature.

The TDS describes E57-89H as having 100% active content and a theoretical VOC content of zero. It identifies the heat-resistance grade as H–C (≥180°C). The thermal classification and operating temperature of finished equipment should be established through validation of the complete insulation system.

Key Features and Benefits：

  · Single-Component Epoxy Formulation: Simplifies preparation by eliminating the need to mix separate resin and hardener components before use.

  · Solvent-Free, Low-Odor Formulation: Described in the TDS as having 100% active content and theoretical zero VOC. These formulation statements do not replace process-specific emissions testing or ventilation requirements.

  · Winding Penetration and Wire Compatibility: Designed to penetrate winding assemblies and provide compatibility with enameled wire during impregnation and curing.

  · Bonding at Elevated Temperature: Specified bonding force is ≥120 N under normal conditions and ≥80 N at 180 ± 2°C, supporting mechanical reinforcement of windings.

  · Thermal Conductivity: A specified value of ≥0.4 W/(m·K) supports heat transfer within the impregnated assembly. Actual motor temperature rise depends on the motor design, impregnation quality, and operating conditions.

  · Electrical Performance After Water Exposure: Dielectric strength remains ≥22 MV/m after 24 hours of water immersion at 20 ± 5°C under the stated test conditions.

  · High-Temperature Electrical Insulation: Volume resistivity is specified at ≥1.2 × 10⁹ Ω·cm at 180 ± 2°C.

  · Resistance to Specified Oils: Following the listed 24-hour oil exposure test at 180 ± 2°C, the film remains smooth and even, without bubbles or cracking.

  · Vacuum and Trickle Impregnation Options: Supports two application methods for different winding designs and production requirements.

Typical Applications：

E57-89H motor winding insulating varnish is intended for impregnation of:

  · Three-Phase Induction Motors: Winding and stator insulation requiring electrical performance and mechanical reinforcement.

  · Permanent Magnet Motors: Impregnation of winding assemblies in permanent magnet motor designs.

  · Automotive Motors: Insulation and bonding of motor windings used in automotive applications.

  · Water Pump Motors: Impregnation of motor windings and applicable rotor coil assemblies.

  · Fractional-Horsepower Motors: Insulation treatment of smaller motor winding assemblies.

  · High-Power Electric Tools: Motor winding impregnation for power tool applications.

  · Round-Wire and Flat-Wire Coils: Impregnation of small and medium-sized coils and windings, including bare flat-wire rotor coils.

  · Electrical Reactors: Insulation treatment of small and medium-sized reactor windings made with round or flat conductors.

Physical Properties：

The following physical, electrical, thermal, and mechanical properties are reported in the TDS. Test methods reference GB/T 15022.2-2017 unless otherwise indicated.

Technical Notes:

  · Viscosity is expressed as cup flow time in seconds.

  · Volume resistivity values are reported in Ω·cm.

  · Bonding performance is reported as force in N, as specified in the TDS.

  · Oil resistance results apply to the listed test conditions and oils; compatibility with other fluids requires evaluation.

Application Guidance：

  · Preparation and Viscosity Adjustment

Check the varnish condition and working viscosity before application. The TDS notes that viscosity may increase during initial storage. Use the specified X-101 diluent to adjust the material to the required application viscosity according to the supplier’s instructions.

Do not mix E57-89H with other products. Establish the working viscosity through trials using the actual winding structure and impregnation equipment.

  · Vacuum Impregnation

Place the stator in the impregnation tank and introduce the varnish under negative pressure. The TDS gives a reference immersion or pressure-holding period of 30 minutes.

Confirm the vacuum setpoint and pressure convention with the supplier before setting up the process, as the supplied TDS does not clearly specify the unit for its stated vacuum value.

After impregnation, remove the workpiece and allow it to drain for more than 30 minutes before baking.

  · Trickle Impregnation

Preheat the workpiece to approximately 50°C before starting trickle impregnation, as recommended in the TDS. Adjust varnish delivery and processing time to achieve adequate impregnation of the actual winding assembly.

  · Thermal Curing

The performance table specifies curing at 135–145°C for at least 4 hours. The separate vacuum impregnation guidance describes baking at 135°C for 3–6 hours, or until the motor resistance reading stabilizes.

Confirm the appropriate production schedule with the supplier and validate curing on the actual component. Account for component size, thermal mass, oven loading, and the time required for the winding to reach the target temperature.

  · Ventilation

Provide ventilation and ducted exhaust during vacuum processing, pressure release, and baking. Maintain these controls when processing this solvent-free, low-odor formulation.

Precautions：

  · Determine the dilution ratio, baking temperature, and baking time experimentally based on product shape, size, and specific requirements. 

  · The product may absorb moisture and turn whitish under high humidity; performance remains unaffected after baking.

  · This product is flammable; keep away from fire and heat sources.

Packaging, Storage/Transport & Shelf Life：

  · Packaging: metal pails, 18 KG/pail

  · Storage & transport: flammable chemical — keep away from fire and heat; handle per regulations; store cool (RT), dark and dry.

  · Shelf life: stored sealed, 6 months at 5-25℃.