Electrical insulating varnish МЛ-92

For the processing of transformer windings, electrical parts and apparatus, a special electrically insulating varnish is used. Such funds can be of three types:

• Impregnating, which are used to improve the electrical conductivity. They fill all the free space between the wires, connecting them together.

• Coverslips, which are used as an additional protection of already treated surfaces.

• Adhesive. Connect several electrical insulating elements among themselves.

One of the impregnating agents for electrical insulation is the ML-92 varnish.

Characteristics and basic properties

This means due to its electrical insulation properties withstand the effects of current, electric arc, electrical stress. The varnish has good insulation characteristics, which does not change in any way when exposed to moisture or steam.

Features of the film formed on the surface after using a varnish:

• Oil resistant.
• Has good electrical strength at various temperatures
• Resistant to heat
• Thermoplastic (withstands more than two days at a temperature of 148-152 degrees).

Under normal conditions (temperature 20 degrees), the conditional viscosity is 25-50 s. The hardness of the film under the same conditions is more than 0.4 standard units.

ML-92 varnish after drying forms a protective coating on the winding surface, which is resistant to various weather conditions. It can withstand temperatures of up to plus 130 degrees. According to GOST-8865 this product belongs to the class "B" for heat resistance.

Apply lacquer outdoors under the open sky or under a canopy. In closed spaces where the conditions are similar to street temperatures and humidity, fresh air is supplied, exhaust ventilation works, it is also permissible to use ML-92 varnish.

The price of the money is 100-600 rubles per 1 kilogram. The cost varies depending on the manufacturer, class, packaging.

The electroinsulating varnish is a homogeneous liquid without mechanical inclusions, consisting of glyptal varnish and melamine-formaldehyde resins. Dilute the lacquer with organic solvents (toluene, xylene or their mixture with white spirit). The content of non-volatile substances is 50-55%.

The surface treated with varnish becomes homogeneous, glossy, smooth, brown (the shade can vary from light to dark).

The consumption of the agent is estimated as 40-50 g / m ² when applying one layer 20-30 μm thick.

The electrical strength of the medium depends on the temperature. Under normal conditions (18-22 degrees plus sign), this value is 70 megawatts / m. With an increase in temperature to 130 degrees, the electrical strength is reduced to 40 MV / m. When the varnish is in a humid environment for 24 hours at a temperature of 20 degrees, the electrical strength will be 30 MV / m.

Application

Apply an insulation compound on a dry, dust-free and dirt-free surface.

Before use, the lacquer is thoroughly mixed. It is used at an air temperature from minus 60 to plus 130 degrees.

ML-92 varnish is applied by two methods:

• In bulk;
• Dipping.

Lacquer layer should be uniform, without streaks.

It is recommended to apply 1-2 layers. Between application it is maintained for 15-20 minutes (at 20 degrees). The same interval is maintained between the last layer and hot drying. Dry for an hour at 105-110 degrees. In multi-layer application, the ML-92 varnish is dried at a temperature of 120 degrees for about 16 hours.

Packing and Storage

Electro-insulating lacquer ML-92 is produced in industrial containers weighing 15 (flask), 25 (drum), 57 kg (barrel).

It is allowed to store the product in a tightly closed container in places where moisture does not penetrate, direct sunlight and there is no exposure to high temperatures. If the necessary conditions are met, the shelf life is one year from the production date.

Safety precautions

The ML-92 varnish emits into the air the volatile chemicals present in its composition. Therefore, when used indoors, good ventilation should be provided. At the end of work, the room must be thoroughly ventilated.

When working with an electrical insulator, personal protective equipment (rubber gloves) should be used.

Do not use near an open flame. Observe the rules of fire safety.