__
GOSS O-Cores
GOSS O-Cores with true circular cross-section provide higher power density and a lower profile than standard toroids. We supply high-efficiency grain-oriented silicon steel O-cores in standard and large custom sizes (up to 1400mm OD / 800kg) for datacenters, BESS, renewable energy, and next-generation high-efficiency transformer designs.
Custom GOSS Toroidal O-Cores
Bridgeport Magnetics supplies high-efficiency GOSS O-Cores with true circular cross-section design for superior power density and lower profile compared to standard toroidal cores. Available in standard sizes and large custom configurations (up to 1400mm OD / 800kg), these grain-oriented silicon steel O-cores are ideal for space-constrained, high-performance applications in datacenters, BESS, renewable energy systems, and next-generation transformer designs
Why Choose GOSS Toroidal O-Cores for High-Power Applications
Grain-oriented silicon steel (GOSS) O-Cores feature a true circular cross-section design that delivers higher power density and a lower profile than standard toroidal cores. This geometry allows windings to follow the core curvature closely, resulting in excellent magnetic efficiency, lower core losses, and reduced electromagnetic interference.
For engineers designing compact or high-performance systems, this translates to:
- Higher power in a smaller, lower-profile package
- Improved efficiency and reduced heat generation
- Lower stray magnetic fields for dense installations
- Ideal solution for next-generation space-constrained transformer designs
Specifications
| Part Number | VA Range @ 60Hz | ID (in) | OD (in) | Cross Section Diameter (in) | Cross Section (square in) | Weight (lbs) |
|---|---|---|---|---|---|---|
| OA-10 | 12 – 24 | 1.26 | 2.52 | 0.65 | 0.33 | 0.57 |
| OA-20 | 24 – 48 | 1.38 | 2.83 | 0.73 | 0.42 | 0.81 |
| OA-30 | 36 – 72 | 1.50 | 2.95 | 0.79 | 0.49 | 0.92 |
| OA-40 | 48 – 96 | 1.57 | 3.15 | 0.85 | 0.54 | 1.12 |
| OA-50 | 60 – 120 | 1.65 | 3.39 | 0.93 | 0.60 | 1.43 |
| OA-80 | 96 – 192 | 1.77 | 3.62 | 0.98 | 0.76 | 1.74 |
| OA-100 | 120 – 240 | 1.89 | 3.86 | 1.04 | 0.82 | 2.09 |
| OA-120 | 144 – 288 | 1.97 | 4.13 | 1.08 | 0.93 | 2.53 |
| OA-150 | 180 – 360 | 2.05 | 4.25 | 1.14 | 1.04 | 2.79 |
| OA-200 | 240 – 480 | 2.17 | 4.53 | 1.24 | 1.21 | 3.45 |
| OA-250 | 300 – 600 | 2.28 | 4.80 | 1.32 | 1.35 | 4.05 |
| OA-300 | 360 – 720 | 2.28 | 5.04 | 1.38 | 1.48 | 4.47 |
| OA-400 | 480 – 960 | 2.44 | 5.28 | 1.48 | 1.71 | 5.57 |
| OA-500 | 600 – 1,200 | 2.56 | 5.55 | 1.56 | 1.91 | 6.42 |
| OA-600 | 720 – 1,440 | 2.68 | 5.83 | 1.63 | 2.09 | 7.41 |
| OA-800 | 960 – 1,920 | 2.83 | 6.18 | 1.73 | 2.41 | 8.78 |
| OA-1000 | 1,200 – 2,400 | 2.95 | 6.54 | 1.85 | 2.70 | 10.65 |
Toroidal O-Core Advantages Over Standard Toroidal Cores
GOSS O-Cores feature a true circular cross-section that provides higher power density and a lower profile than conventional toroidal cores. The rounded geometry allows windings to follow the core curvature perfectly, resulting in superior efficiency and material savings.
Key Product Features & Benefits:
- Compact Dimensions: The circular cross-section reduces circumference by ~12% vs. a square and ~18% vs. a 1:2 rectangle of the same area, delivering a lower height with only a modestly larger OD.
- Lighter & More Efficient: 30-40% lighter and more compact than E-I transformers; magnetic flux runs parallel to grain orientation throughout the core.
- Significant Wire Savings: Evenly distributed windings result in shorter mean turn length, saving 10-15% in magnet wire.
- Lower Manufacturing Cost: No need for epoxy coating (saves 20-30% vs. coated toroids); simple 50% overlap taping provides sufficient insulation due to the rounded shape.
- Improved Winding Quality: Eliminates barrel shape issues common with square cores and reduces stress on winding machines, especially with heavy wire.
These advantages make GOSS O-Cores the preferred choice for space-constrained, high-efficiency transformer designs in datacenters, BESS, and renewable energy systems.
Toroidal Transformer O-Cores shine in high power density, Compact Profile, highly efficient applications.
Battery Energy Storage Systems (BESS)
High-power density BESS inverters and converters
Data Center Power Systems
Compact high-density UPS and rack power supplies
Renewable Energy Inverters
Space-saving solar and wind power inverters
Industrial Compact Power Supplies
Low-profile industrial motor drives and UPS
Next-Generation Custom Transformers
High-efficiency new transformer designs and prototypes
Let's build yours to spec.
Custom magnetics engineered and manufactured in the USA. Tell us your requirements and our engineers will help.
Frequently Asked Questions
What are GOSS O-Cores and how do they differ from standard toroidal cores?
GOSS O-Cores feature a true circular cross-section that provides higher power density and a lower profile than conventional toroidal cores, while maintaining excellent magnetic efficiency.
What are the main advantages of O-Core toroidal transformers?
O-Cores excel in power density, compact profile, and material efficiency — delivering more power in a smaller package, saving 10-15% on magnet wire, and reducing overall height for space-constrained designs.
What industries benefit most from large GOSS O-Cores?
Data centers, BESS, renewable energy inverters, industrial power supplies, and next-generation high-efficiency transformer designs benefit most from the low-profile and high-density advantages of O-Cores.
How large can custom GOSS O-Cores be manufactured?
We supply O-Cores in large custom sizes up to 1400mm outer diameter and 800kg, ideal for high-power applications requiring superior efficiency and compact form factors.
Why choose O-Cores for new transformer designs?
Engineers choose O-Cores for their circular cross-section that enables higher power density, lower material costs, and better space utilization in modern compact and high-efficiency transformer projects.
Do O-Cores require epoxy coating like standard toroids?
No – simple taping with 50% overlap is sufficient due to the rounded shape, which eliminates edge cut-through risk and saves 20-30% compared to epoxy-coated toroidal cores.
