Transformer, Busduct & Busway Flexible Links
Carsai manufactures custom bus duct flexible link and transformer flexible connector products for transformers, switchgear, busduct systems, busways and industrial power-distribution equipment.
These connectors provide an electrical path between rigid conductors while accommodating vibration, thermal expansion, equipment movement and minor terminal misalignment.
Available constructions include:
- Laminated copper foil connectors
- Braided copper flexible links
- Stranded copper connectors
- Multilayer flexible busbars
- Transformer palm connectors
- Busduct expansion links
- Insulated flexible connectors
- Bare and tin-plated copper assemblies
- Custom single-hole and multi-hole terminals
Each product is manufactured according to the customer’s drawing, current requirement, terminal arrangement and installation conditions.
For our complete range of conductor structures, visit our Flexible Busbar Manufacturer page.
What Is a Busduct Flexible Link?
A busduct flexible link connects rigid busbar sections or joins a busduct system to another item of electrical equipment.
Related search phrases include:
- Busduct flexible bar
- Flexible link busduct
- Flexible link for busduct
- Flexible link busway
- Busway flexible link
- Copper flexible for bus duct
The flexible section helps reduce mechanical stress at the connection point.
It may accommodate:
- Thermal expansion of long busbar runs
- Transformer vibration
- Installation tolerance
- Differences in terminal height
- Minor equipment movement
- Expansion and contraction during operation
A flexible link does not replace correct system alignment or mechanical support. The connected equipment and rigid busbars should still be installed within the permitted dimensional tolerances.
Transformer Flexible Busbars
A transformer flexible busbar connects transformer terminals to switchgear, busducts, breakers or rigid copper busbars.
The phrases flexible busbar for transformer, transformer flexible link, transformer flex link and flexible link for transformer generally describe closely related products.
Transformer connections may experience:
- Continuous vibration
- Heating and cooling cycles
- Terminal movement
- Installation misalignment
- Mechanical force from rigid busbars
- High continuous current
A flexible connector helps prevent these forces from being transferred directly to the transformer terminal.
Applications include:
- Dry-type transformers
- Oil-filled transformers
- Rectifier transformers
- Distribution transformers
- Industrial transformers
- Transformer-to-switchgear connections
- Transformer-to-busway connections
Main Flexible-Link Constructions
Laminated copper foil links
A transformer laminated flexible link uses multiple thin copper foils stacked together.
The center section remains flexible, while the terminal ends are compressed or welded into solid connection areas.
Related product names include:
- Laminated copper transformer connector
- Transformer copper foil flexible connector
- Laminated flexible link for transformer
- Busduct laminated flexible link
- Busway laminated copper connector
Laminated copper links provide:
- A broad, flat current path
- Controlled bending direction
- Compact installation
- Large terminal contact areas
- Custom layer count and foil thickness
- Easy partial insulation
They are especially suitable when the connected terminals are broad and flat.
Braided copper connectors
A flexible braided connector bus duct product uses fine copper wires woven into a flexible conductor.
Braided construction provides:
- High multidirectional flexibility
- Good vibration absorption
- Easy accommodation of misalignment
- Bare or tinned copper options
- Different terminal shapes
- Custom flexible lengths
Braided links may be fitted with solid copper terminal plates or manufactured with press-welded ends.
Stranded copper connectors
Stranded connectors use multiple round copper ropes arranged between terminal plates.
They may be selected when the connection requires:
- A relatively long flexible section
- Greater movement
- Several parallel conductors
- Large multi-hole terminal plates
- Heavy-duty transformer connections
Transformer Flexible Jumpers
A transformer flexible jumper is normally a shorter flexible connection bridging two nearby terminals.
The term flexible jumper for transformer may refer to a connection between:
- A transformer terminal and rigid busbar
- Two terminal palms
- A transformer and circuit breaker
- A transformer and busduct
- A winding terminal and output conductor
Flexible jumpers may be straight, curved or preformed.
Possible designs include:
- Flat laminated jumpers
- Braided copper jumpers
- Parallel stranded copper links
- U-shaped flexible connections
- Offset terminal designs
- Unequal terminal widths
- Different hole patterns at each end
The installed orientation should be shown on the drawing so the connector is formed in the correct direction.
Transformer Palm Connectors
A transformer palm connector is the terminal section used to connect the flexible conductor to a transformer or mating busbar.
The similar phrase palm connector for transformer generally refers to the same terminal form.
Palm connectors may include:
- One mounting hole
- Two-hole terminal patterns
- Four-hole or multi-hole patterns
- Slotted holes
- Rounded or chamfered corners
- Wider terminal sections
- Tinned or silver-plated contact faces
- Different terminal angles
A transformer palm should provide enough contact area for the required current.
Important dimensions include:
- Palm width
- Palm thickness
- Hole diameter
- Hole spacing
- Edge distance
- Contact length
- Surface flatness
- Plating coverage
The conductor itself may contain sufficient copper, but an undersized or uneven terminal can increase contact resistance and temperature.
Busway Flexible Connections
A busway system uses rigid conductive bars inside an enclosure. Flexible links may be installed at equipment interfaces, expansion locations or sections where vibration must be isolated.
A busway flexible link may connect:
- Busway to transformer
- Busway to switchboard
- Busway to generator
- Busway to rectifier
- Two busway sections
- Busway to a rigid busbar assembly
A busway laminated copper connector can be designed to match the busway conductor width and terminal-hole pattern.
Busway and busduct terms are sometimes used interchangeably, although the exact system construction can vary by supplier and region. A drawing is therefore required for accurate quotation.
Materials and Surface Finishes
Bare copper
Bare electrical copper is suitable for many protected indoor transformer and busduct applications.
Tinned copper
Tin plating can help protect copper surfaces from oxidation and provide a consistent bolted-contact finish.
It may be applied to:
- The entire flexible link
- Only the terminal palms
- Individual copper foils before assembly
- Completed press-welded terminal areas
Silver-plated terminals
Silver plating can be applied selectively where required by the switchgear, transformer or busway specification.
Aluminum
Flexible aluminum links can be manufactured for systems using aluminum conductors, subject to the required structure and terminal design.
Copper-to-aluminum connections require an appropriate transition method.
Insulated Flexible Links
Transformer and busduct connectors may be supplied bare or partially insulated.
Available insulation options include:
- Heat-shrink tubing
- PVC sleeves
- Epoxy coating
- Powder coating
- Custom protective covers
The terminal contact areas normally remain exposed.
Insulation boundaries should be shown on the drawing, including:
- Exposed terminal length
- Covered flexible section
- Phase color
- Required material
- Operating voltage
- Operating temperature
Insulation may affect heat dissipation, so it must be considered when the conductor cross-section is selected.
Current Capacity and Thermal Design
A flexible link should not be selected only from a generic current table.
Important inputs include:
- Copper cross-sectional area
- Number and thickness of foil layers
- Braid or strand construction
- Flexible-section length
- Continuous current
- Peak or fault current
- Duty cycle
- Ambient temperature
- Enclosure temperature
- Ventilation
- Terminal contact resistance
- Insulation coverage
- Allowable temperature rise
For laminated copper connectors, the nominal cross-section can be calculated from:
Layer quantity × foil width × foil thickness
For braided and stranded products, conductor size should be based on the total metallic copper area rather than the visible outside dimensions.
Terminal and Geometry Options
Carsai can manufacture flexible links with:
- Single-hole terminals
- Two-hole terminals
- Multi-hole palms
- Round or slotted holes
- Different terminal widths
- Unequal terminal thicknesses
- Offset terminal planes
- Preformed curves
- L-shaped and Z-shaped ends
- Straight or angled palms
- Customer-defined outlines
A three-dimensional drawing is useful when the two terminal ends are positioned on different planes.
Manufacturing and Inspection
A typical custom project includes:
- Reviewing the application and drawing
- Confirming copper grade and conductor structure
- Preparing copper foil, braid or rope
- Forming the flexible section
- Press welding or attaching terminal palms
- Drilling or machining mounting holes
- Producing bends and offsets
- Deburring and cleaning
- Applying plating
- Adding insulation when required
- Inspecting dimensions and terminal surfaces
- Packing the finished products
Inspection may cover:
- Overall length
- Flexible-section length
- Copper cross-section
- Terminal dimensions
- Hole diameter and spacing
- Bend direction and offset
- Palm flatness
- Plating coverage
- Insulation location
- Surface condition
Information Needed for a Quotation
Please provide:
- Transformer, busduct or busway application
- 2D or 3D drawing
- Copper or aluminum material
- Flexible-link construction
- Continuous and peak current
- Conductor dimensions
- Flexible-section length
- Palm dimensions
- Hole quantity and spacing
- Installed terminal orientation
- Bare or plated finish
- Insulation requirement
- Prototype quantity
- Production quantity
A sample or installation photograph with dimensions can support an initial review when a formal drawing is unavailable.
Frequently Asked Questions
Why are flexible links used on transformer terminals?
They help reduce the vibration, thermal-expansion and alignment forces transferred from rigid busbars to the transformer terminals.
Which is better for transformers: laminated foil or copper braid?
Laminated foil provides a broad, flat conductor with controlled bending. Copper braid provides greater multidirectional flexibility. The correct structure depends on current, movement and terminal layout.
Can busduct flexible links have different terminal patterns at each end?
Yes. Each end can have a different width, thickness, hole pattern and mounting orientation.
Can the flexible link be tin or silver plated?
Yes. Full or selective plating can be applied according to the drawing.
Can transformer flexible connectors be insulated?
Yes. Heat-shrink, PVC, epoxy and other insulation options are available with exposed contact palms.
Can you manufacture from an existing connector sample?
Yes. A sample can support initial review, but an approved dimensioned drawing is recommended for repeat production.
Request a Transformer or Busduct Flexible Link Quotation
Carsai manufactures custom transformer flexible connections, laminated copper links, braided connectors and busway expansion links.
Send your application drawing, current, conductor dimensions, terminal palms, hole pattern, finish, insulation and required quantity.
Request a custom transformer, busduct or busway flexible-link quotation from your drawing or sample.
