Toroidal O-Core Power Transformers
Picture shows a regular toroidal and an O-core toroidal transformer with the same power rating.
CUSTOM DESIGNS for 60Hz or 50/60Hz
O-Core power transformers are the preferred choice for applications when a lowest possible profile is a design priority. O-Core transformers have a diameter to height ratio of around 3:1 compared to 2:1 for our regular toroidal transformers.
Since O-Cores have no sharp edges they require less insulation and can be wound with less fill factor resulting in a lighter and smaller transformer than a regular toroidal core transformer.
The grain oriented silicon steel properties of O-Cores are the same as in our regular toroidal cores giving the O-Core transformers the same electrical benefits. They can be used in designs for the same applications.
If your design requires a small footprint our regular toroidal core is a better choice as it offers flexible dimensions.
O-Cores are wound from a steel strip which is continuously pointed towards each end to produce a circular cross section. The circumference of a circle is about 12% less than that of a square with same area and 18% less than a rectangle with the same area and a diameter to height ratio of 2:1 as in the typical regular toroidal core transformer.
Please refer to the chart below for the physical sizes of power ratings up to 2,000VA 60Hz, or 1600VA for 50/60Hz frequencies.
O-Core Transformers
Size and weight of different power ratings
| Power VA @ 60Hz | Power VA @ 50/60Hz | Dimensions * | Weight * |
|---|---|---|---|
| 45 | 36 | 3.0 x 1.0 in (76 x 24 mm) | 1.2 lbs (0.5 kg) |
| 65 | 52 | 3.2 x 1.0 in (80 x 26 mm) | 1.4 lbs (0.6 kg) |
| 90 | 72 | 3.4 x 1.1 in (86 x 28 mm) | 1.7 lbs (0.8 kg) |
| 115 | 92 | 3.7 x 1.2 in (93 x 30 mm) | 2.2 lbs (1.0 kg) |
| 175 | 140 | 3.9 x 1.3 in (99 x 32 mm) | 2.7 lbs (1.2 kg) |
| 220 | 176 | 4.2 x 1.4 in (105 x 34 mm) | 3.2 lbs (1.5 kg) |
| 275 | 220 | 4.5 x 1.4 in (113 x 36 mm) | 3.8 lbs (1.7 kg) |
| 320 | 256 | 4.6 x 1.5 in (116 x 38 mm) | 4.2 lbs (1.9 kg) |
| 425 | 340 | 4.9 x 1.6 in (124 x 41 mm) | 5.2 lbs (2.4 kg) |
| 550 | 440 | 5.2 x 1.7 in (131 x 43 mm) | 6.1 lbs (2.8 kg) |
| 650 | 520 | 5.4 x 1.8 in (138 x 45 mm) | 6.8 lbs (3.1 kg) |
| 800 | 640 | 5.7 x 1.9 in (144 x 49 mm) | 8.5 lbs (3.9 kg) |
| 1000 | 800 | 6.0 x 2.05 in (152 x 52 mm) | 9.8 lbs (4.5 kg) |
| 1300 | 1040 | 6.3 x 2.1 in (159 x 54 mm) | 12.5 lbs (5.7 kg) |
| 1600 | 1280 | 6.7 x 2.3 in (169 x 57 mm) | 15.0 lbs (6.8 kg) |
| 2000 | 1600 | 7.0 x 2.4 in (179 x 61 mm) | 17.5 lbs (7.9 kg) |
