Transformer Applications
POWER TRANSFORMERS
TRANSFORMERS (GENERALLY) FALL INTO TWO CATEGORIES: DRY-TYPE TRANSFORMERS AND LIQUID OR OIL-FILLED TRANSFORMERS.
Even though the primary components are similar between dry and oil-filled transformers (core, coil, leads, etc.), the insulation can be quite different. Dry-type transformers utilize safety-certified CSA and UL-recognized high-temperature insulation systems, whereas oil-filled transformers use oil and high dielectric strength wood-based insulation materials.
The Gund Company manufactures a wide range of insulation components for various types of transformers. Our application engineering expertise can help our customers understand their insulation material selection and component design options, from large oil-filled transformers to dry-type distribution transformers or low-voltage electronics transformers.
OIL-FILLED TRANSFORMERS
Oil-filled transformers use dielectric oil to insulate and cool the windings of the transformers.
With the dielectric oil’s benefit to cool the transformer winding, relatively low-temperature insulation materials can be used in these designs. Typical insulation materials are cellulose-based products such as pressboard and laminated wood with relative temperature indices range from 80°C to 105°C. Oil-filled transformers are most commonly classified as power or distribution, depending on their size and application. The Gund Company supplies a range of insulating materials and components for each type of transformer.
POWER TRANSFORMERS
Power transformers are large, oil-filled transformers and are commonly divided by their rated power.
The small power transformer classification typically starts around 10 MVA with a maximum service voltage of 145 kV. Medium power transformers range from about 30 MVA to about 100 MVA and commonly work as network and generator step-up transformers. The large power transformer classification includes transformers with ratings greater than 100 MVA and voltages greater than 345 kV. The Gund Company supplies a wide variety of insulation components for the full range of power transformer designs and ratings:
- Core Insulation Kits
- Step Blocks
- Core Blocks
- Fletch Plates
- Core Filler Rods
- Lead & Cleat Structure
- Support & Yoke Beams Insulation
- Fasteners (Rods & Nuts)
- Winding Forms
- Dovetail Strips
- Key Spacers
- Camping Rings
- Coil Support Blocks
- Washer Assembly
- Tap Changer Boards
- Tap Changer, Filament-Wound Housings
- Lead Clamps
- Lead Conduit Tubes
- Tap Changer Enclosure Gaskets
- Bushing Gaskets & O-Rings
- Radiator Gaskets
- Hand-hole and Man-hole Gaskets
| Common Rigid Insulation Materials in Dry-Type Transformers | ||
|---|---|---|
 Rigid Insulation |
||
| GPO-3, UPGM 203 | Class F GPO-1 (N155) | |
| Class H GPO-1 (N180) | Class R GPO-1 (N220) | |
| Convolute Wound Tubing | Filament Wound Tubing | |
| Flexible, High-Temp GPO | NEMA GPO-1, UPGM 201 | |
| GPO-3 Angles & Chanels | NEMA G-10, EPGC 201 | |
| NEMA G-11, EPGC 203 | SG-200 & HST-II | |
| Standoff Insulators | Threaded Rods & Nuts | |
| UPGM 205, U205 | and more… | |
| Common Elastomeric Materials in Power Transformers | ||
|---|---|---|
 Gasket & O-Ring Materials |
||
| Buna-N | Cork | |
| Cork-Nitrile | Cork-Rubber | |
| Fluorocarbon | Fluorosilicone | |
| Nitrile | Sponge | |
| Viton | and more… | |
| Click here to learn more about transformer gasket & sealing materials. | ||
DISTRIBUTION TRANSFORMERS
OIL-FILLED DISTRIBUTION TRANSFORMERS ARE MOST COMMONLY POLE-MOUNTED OR PAD-MOUNTED.
Pole-mounted distribution transformers are so named because they are mounted to utility poles in most older urban or rural areas.
In suburban areas, built within the last few decades, most distribution lines are buried underground, so transformers are mounted on concrete pads in residential, commercial, or light industrial applications. The Gund Company manufactures and fabricates a variety of insulation material solutions for distribution transformers:
- Layer Insulation
- Layer Insulation Tape
- Core Step Blocks
- Coil Supports
- Hardboard Coil Packing & Shims
- Phase Barriers
- Ground Barriers
- Sight Window Barriers
- Lead Supports, Spacers & Clamps
- Fuse Boards
- Fuse Tubes
- Tap Changer Boards
- Enclosure Gaskets
- Bushing Gaskets
- O-Rings
| Common Flexible Insulation Materials in Dry-Type Transformers | ||
|---|---|---|
 Flexible Insulation |
Nomex® Meta-Aramid Paper | G-Flex™ Meta-Aramid Paper |
| 3M Cequin® | 3M Tufquin® | |
| 3M Thermavolt® | Kapton® Polyimide Film | |
| DMD | PET Polyester Film | |
| NMN | Click here to view additional material datasheets. | |
| Common Rigid Insulation Materials in Dry-Type Transformers | ||
|---|---|---|
 Rigid Insulation |
||
| GPO-3, UPGM 203 | Class F GPO-1 (N155) | |
| Class H GPO-1 (N180) | Class R GPO-1 (N220) | |
| Convolute Wound Tubing | Filament Wound Tubing | |
| Flexible, High-Temp GPO | NEMA GPO-1, UPGM 201 | |
| GPO-3 Angles & Chanels | NEMA G-10, EPGC 201 | |
| NEMA G-11, EPGC 203 | SG-200 & HST-II | |
| Standoff Insulators | Threaded Rods & Nuts | |
| UPGM 205, U205 | and more… | |
| Common Elastomeric Materials in Power Transformers | ||
|---|---|---|
| Gasket & O-Ring Materials |
||
| Buna-N | Cork | |
| Cork-Nitrile | Cork-Rubber | |
| Fluorocarbon | Fluorosilicone | |
| Nitrile | Sponge | |
| Viton | and more… | |
| Click here to learn more about transformer gasket & sealing materials. | ||
TRANSFORMER PRODUCTS
G-Flex™ is The Gund Company’s brand of flexible insulation products. G-Flex™ product line includes aramid paper, flexible laminates, wire sleeving, felts, cordage and surge ropes, and insulating tapes.
The G-Flex™ is used in a variety of electrical applications. Some specific examples are transformer coil layer insulation, motor slot insulation, lead wire protection, insulation barriers, and numerous other applications.
G-Flex™ Markets
- Motors & Generators
- Transformers
Ranprex® laminated densified wood manufactured by Rancan is a widely used material in the Oil Immersed Power & Distribution Transformer Industry.
End-User Applications- Clamping or pressure rings
- Core blocks
- Step blocks
- Cooling plates
- Lead and cleat structures
- Pressure beams
- Fasteners (threaded rod & nuts)
- Round spacers
- Coil supports
- Shield rings
