Non Grain Oriented Electrical Steel (NGOES)
Arnold Rolled Products' Non Grain Oriented Electrical Steel (NGOES) is manufactured in thicknesses of 0.005” and 0.007” (0.127 mm and 0.178 mm) under the trade names ArnonTM 5 and ArnonTM 7. It is produced by rolling a heavier gauge 3% silicon steel Grain Oriented Electrical Steel (GOES) to the required thickness and then “unorienting” it. This unique proprietary processing creates a thin gauge steel with superior properties for use in many applications in the Industrial, Aerospase & Defense, Semiconductor, and Medical markets.
Arnon is frequently used as laminations in motors and generators. A common lamination thickness (gauge) is 0.014" to 0.032” (0.356 mm to 0.813 mm) where Arnon 5 and Arnon 7 are 0.005" and 0.007" (0.127 mm and 0.178 mm) thin respectively. The laminations are located in either the rotor or the stator depending on the design because the laminated structure can be either rotating or stationary. The laminations are generally made from a NGOES since they are circular and the magnetics are equal in all directions. For lower frequency applications, below 400 Hz, there is no known great advantage to using the thinner material; however, as we go higher in frequency, the eddy currents increase and the use of a thinner material will offset this effect.
Heat build up is a major problem in motors and the use of thin laminations reduces the heat build up due to reduced eddy current losses. This also means that the motor uses less energy (heat is wasted energy) so we have a more efficient unit. This may allow for a fully enclosed motor with no external cooling required which can be very important in critical designs.
Although it has been on the market for over twenty years, Arnon has recently received more attention due to the need for materials that can be used at higher frequencies. The thin Arnon benefits from both its thickness as well as lower inherent core loss to give a material that provides low heat build up and allows for higher efficiency. In testing, Arnon has proven to offer as much as 45% lower core loss than other NGOES. This translates into significantly higher efficiency. Some motors using Arnon have been tested at in excess of 97% efficiency.
Benefits and Advantages
- Thin gauge Arnon provides efficiency improvements particularly at higher frequencies. Below 400 Hz the
loss differential is minimal. But as the frequency increases, the loss differential becomes exponentially greater.
- Arnon is usable at higher frequencies than cobalt-iron (Hiperco 50) materials. The Co-Fe materials are not
recommended for over 1200 Hz whereas Si-Fe is the preferred material to at least 10 KHz.
- Arnon is significantly less expensive than Co-Fe (Hiperco 50) (about 1/3 of the cost of Hiperco 50). Hiperco 50
is the Carpenter trade name for a 50% cobalt material similar to Vanadium Permendur. It is used for motor laminations
and for transformer cores where improvements in magnetic properties outweigh higher core loss.
- Low coercivity coupled with the hysteresis curve shape of Arnon provide reduced hysteresis loss in rotating machinery.
This means a motor or generator will run more efficiently and with less heat buildup and that leads to better performance
(e.g. improved torque density) and/or the ability to maintain constant RPM’S under load. Core loss is energy lost to heat.
- Arnon exhibits up to 50% lower core loss than competitive non-oriented silicon steel when driven by the same field.
This confirms the importance of the lower coercivity of Arnon coupled with improved hysteresis curve shape.
- Low loss Arnon is especially useful in totally enclosed motor designs where heat cannot be easily removed.
More information can be found on the benefits and advantages of using Arnon in the following presentations:
Capabilities Information
Hysteresis Curves
Magnetization Curves
Core Loss Curves
