Q1: What Is an Oil Duct Spacer in a Transformer?
Answer:
An oil duct spacer is an insulating component inserted between winding layers of a transformer. It helps maintain a uniform cooling channel, allowing transformer oil to circulate efficiently, remove heat, and preserve dielectric integrity.
You may also hear these called:
➡️ Oil duct strips, transformer cooling duct spacers, or channel spacers
Q2: What Are Oil Duct Spacers Made Of?
Answer:
The most commonly used materials include:
- Pressboard (conforming to IEC 60641)
- Pre-compressed pressboard for added rigidity
- Epoxy-laminated paper for bonded structural stability
- FRP (Fiberglass Reinforced Plastic) — often used in duct spacer for dry-type transformer builds
✅ These materials offer excellent dielectric strength, oil resistance, and mechanical stability.
Q3: Where Are Duct Spacers Used Inside Transformers?
Answer:
Duct spacers are placed in various insulation-critical zones:
- Between LV and HV winding layers
- In radial and axial oil channel insulation pathways
- Between phase coils in dry-type transformers
- Inside core clamp insulation packages
They ensure both structural integrity and fluid/air flow across coil structures.
Q4: What Properties Define a Good Oil Duct Spacer?
Answer:
- Uniform thickness across the entire batch
- Chamfered or rounded edges to reduce oil flow blockage
- Certified materials (IEC 60641, SGS-tested, or RoHS-compliant)
- Precision-matched with CNC processing and insulation layout drawings
✅ These features ensure consistent performance and safe integration into transformer windings.
Q5: Can I Get Custom-Cut or CNC-Shaped Spacers?
Answer:
Yes. Many suppliers offer custom insulation spacer strips that are CNC-cut to match your winding geometry. Capabilities include:
- Support for DXF, DWG, and PDF drawing inputs
- Grooving, slotting, corner rounding, and multi-tabbed profiles
- Pre-kitted packaging per transformer model
📌 See our CNC Spacer Capabilities
Q6: What’s the Typical MOQ and Delivery Time?
Answer:
For transformer OEMs and repair service providers:
- ✅ MOQ: 100 pcs per size
- ⏱️ Lead Time: 5–12 working days for CNC-processed batches
- 📦 Sample Support: Drawing-based samples available for test fitting
Many oil duct spacer suppliers offer low-volume support for design validation or repair use.
Q7: What’s the Difference Between Oil Duct Spacer Strips and Spacer Blocks?
| Feature | Spacer Strip | Spacer Block |
|---|---|---|
| Shape | Long, thin insulating strip | Short, thick, often grooved |
| Function | Maintains consistent oil gap | Adds mechanical support |
| Application | Radial/vertical flow paths | Core clamps, structural layers |
📌 Compare strip vs block applications here
Q8: Can I Use Duct Spacers in Dry-Type Transformers?
Answer:
Absolutely. In dry-type transformers, airflow replaces oil, but duct spacers are still vital for maintaining cooling gaps.
Materials should be:
- Flame-retardant (FRP or thermal-grade laminated board)
- Mechanically rigid under heat
- Safe for class F/H thermal environments
✅ These are critical in high-efficiency dry-type coils with natural or forced air cooling systems.
Final Takeaway
Oil duct spacers are important parts of transformer insulation systems. They keep oil or air channels open, reduce heat buildup, and stabilize winding shape.
Choosing the right material, shape, and supplier is important for both oil-immersed and dry-type transformers. This choice affects their performance and lifespan.
Contact Section (CTA)
📩 Need help selecting duct spacers for your transformer coil layout?
We support OEM designs with engineering evaluation, CNC layout review, and IEC-compliant materials.
🔘 [Request a Factory Quote + Lead Time]
🔘 [Download Our CNC Spacer Catalog PDF]
Phone: +86-15958243831
Email: jessie.feng@sidanm.com
Whatsapp: https://wa.me/8615958243831
