Precision clamping for oil-immersed and dry-type distribution transformers
What a core clamp does
The core clamp is the frame that holds a transformer's laminated iron core rigidly in place. It keeps the core stacked and square, clamps it against vibration and short-circuit forces, and gives the core a solid mechanical seat inside the tank or dry-type enclosure. It is a small part with an outsized job: if the core moves, losses rise, noise rises, and the transformer's life shortens.
We fabricate core clamps for oil-immersed transformers up to 500 kV, dry-type transformers, power transformers and reactor cores - always to the customer's drawing and order configuration.
Product range & where clamps are used
| Type | Applied to | Notes |
|---|---|---|
| Oil-immersed transformer clamp | Oil-immersed distribution and power transformers, up to 500 kV | Fabricated steel clamp frames, painted |
| Dry-type transformer clamp | Cast-resin and dry-type distribution transformers | Matched to the dry-type core and enclosure |
| Power transformer clamp | Larger power-transformer cores | Heavier section, higher clamping force |
| Reactor core clamp | Reactor (choke) cores | Clamping matched to the reactor's core stack |
Material & specification
| Item | Specification |
|---|---|
| Structural steel | Q235B (GB/T 700) - general clamp frames, good weldability, economical |
| High-strength steel | Q345B (GB/T 1591) - higher-yield clamp frames for larger, heavier cores |
| Core interface | Flat, burr-free clamping faces that protect CRGO silicon-steel laminations |
| Fabrication | Cut, formed and welded to drawing; jig-controlled hole positions |
| Finish | Shot blast + anti-rust primer + high-temperature baked paint (colour to spec) |
| Customisation | Full - machined to CAD (DWG/DXF) or PDF drawings |
Surface treatment & corrosion resistance
Clamps live in humid, oily transformer environments, so the finish is part of the product, not decoration:
Shot blasting - removes mill scale and rust, gives a uniform, anchor-profile surface for coating adhesion.
Anti-rust primer - base corrosion protection before topcoat.
High-temperature baked paint - a hard, durable, heat-resistant finish that holds colour and protects in service.
Pickling & passivation - for stainless or specialist surfaces, giving a clean, corrosion-resistant skin.
Dimensional tolerance & custom machining
Every clamp is made to drawing, with the tolerances that matter for a clean core fit:
| Control point | What we inspect |
|---|---|
| Clamping-face flatness | Against the drawing, so the core seats without gaps |
| Hole pitch & position | Jig-controlled and inspected, so bolts align first time |
| Overall dimensions | To drawing, before dispatch |
| Drawing input | CAD (DWG/DXF) or PDF accepted for quotation and production |
If you have a sample instead of a drawing, send it and we will work
Quality control
Quality-management system - production runs under a certified quality-management system, with material certificates on request.
FMEA-based process control - process risk is reviewed up front (failure-mode approach), so critical dimensions and welds are controlled before they become defects.
Dimensional inspection - flatness, hole pitch and overall dimensions checked against the drawing.
Weld quality - welding to an agreed standard, with non-destructive testing (NDT) available on request.
Trusted by global transformer manufacturers
Our clamps, tanks and radiators are supplied into the transformer-manufacturing supply chain, including TBEA, DAQO Group, AUX, CREAT, YiDEA and DOMAIN Electric Group. For export orders we supply with material certificates, dimensional inspection records and export packing to suit the destination.
Made for repeat orders
Core clamps are a regular, repeating order for transformer manufacturers - the same families are built again and again. That is where our process earns its keep:
Regular order configuration - built to a fixed, repeatable configuration, so each batch matches the last.
Simple, stable processing - controlled tooling keeps quality consistent and cost predictable.
Reliable supply - stable capacity behind steady repeat orders, so your line is never held up waiting for clamps.
To quote accurately, we need:
Transformer type - oil-immersed, dry-type, power transformer or reactor
Core dimensions and clamp drawing (CAD/PDF) or sample
Material - Q235B, Q345B or specified grade
Surface finish and paint colour
Order quantity and expected repeat schedule
Inspection, NDT and packing requirements
Standards
Fabricated to the customer's drawing and order specification, with dimensional inspection before dispatch; material to GB/T 700 (Q235B) and GB/T 1591 (Q345B) or as specified.
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