Specifying POWER CONDITIONING Transformers


Power Conditioning refers to restoration of a 60 (or 50) Hz fundamental power wave by removal of the non-sinusoidal components that were not present at the time of generation.

Power Conditioning Has Become a Necessity

None of the power grids in use today were planned, intended, nor are they qualified to carry the vast myriad of noise, spikes, transients, and harmonic rich distortion superimposed onto the fundamental power wave.

Plitron solution for power line noise.

Graphical Representation of Noise on the power grid.

Though the hydro utilities generate and distribute clean pure sinusoidal sine waves at the source, the combined downstream noise emitted en route pollutes the grids and the sends low-grade power to every user. It is a growing problem, somewhat unforeseen, referred to as ‘the new pollution’ by some, has grown exponentially in the last three decades, and there is no widespread accepted solution.

The source of the noise is non-linear and switching power supplies – which are common in every household and every computer – that spawns and feeds destructive harmonics back into the grid where they are shared by all. It is not an industrial issue any more, it is a household concern.

Effects of Distorted Waveforms

Being a recent phenomena, there is no definitive information available regarding the long-term health risks of allowing dirty power to circulate in our power grids and in our homes. Harmonics can range in frequency into the RF band, thus are carried in the air and their electromagnetic energy envelopes our rooms.

Low frequency harmonics can consume power, which just circulates and has no practical purpose. There is however much information on consequences to machinery and productivity. HD TV’s lose sharpness and picture quality. Sound systems’ noise floor increases, and your home theatre audio loses definition and clarity.

In brief, electrical fire hazard risks are increased due to the heating effect of harmonics; voltage sags mean equipment draws more current and runs hotter, which means usable life is shortened; power consumption and energy costs increase; and more.

Common Solutions to Cleaning the Mains

The general industry mentality is to introduce external components into the line to filter the unwanted portion of the signal. Power conditioners are commercially available with various degrees of efficiency, which are basically capacitors and inductors used as tuned filter networks to pass the fundamental and roll off to block unwanted frequencies.

Plitron’s Patented NBT (Narrow Bandwidth) Technology

Based on original research, Plitron offers transformer NBT solutions to power quality problems without the requirement for external components. By harnessing the L, C, and R – which are present in every transformer – Plitron has developed technology that allows the transformer to function as a filter. NBT transformer technology is a revolutionary patented (US. Patent #6,087,822) transformer development, with many potential applications in power supply and power conditioning products. The technology solves the problem of electromagnetic noise present in the power supply, while eliminating the need for other external devices.

NBT transformer technology offers significant improvements in bandwidth reduction for power transformers. The frequency bandwidth of most power transformers is always far too broad (it can exceed 200 kHz). The inability of most power transformers to exclude frequencies beyond their operational frequency allows high frequency signals to enter or leave the device. NBT is a transformer-based solution that effectively reduces the electromagnetic noise transferred to and from a sensitive load.

NBT attenuation curves are shown at left, compared to other technologies. NBT transformers are built in toroidal shape, thus offering all the advantages of toroidal technology: more efficient, lighter, gap less, less audible hum and lower stray fields than the standard designs. NBT transformers are the only electromagnetic noise reduction transformers designed in toroidal cores.

Balanced Power

Although Balanced power has gained mainstream acceptance in the audio/video market in the last decade, the concept is not new, and Plitron has built and supplied this technology since our inception in 1984.

The Balanced Power concept consists of a 1:1 isolation transformer (ie 120 VAC In/Out) with a centre tapped secondary winding. The ‘Balance’ refers to a Bifilar wound secondary – meaning both secondary halves are wound simultaneously, turn for turn – thus each of the 60 Volt sections are mirror imaged and matched to the theoretical limit for resistance, capacitance, and inductance. Electrical theory would decree that noise mains noise referred to the secondary halves would be accurately 180 degrees opposed, offsetting, and thus self-canceling and delivered to ground.

The ground reference created is 60 VAC, so this system must operate independently of other electrical circuits. The configuration is covered by electrical codes, and should be installed to comply with regional hydro safety regulations. Balance power attenuation slope is depicted in Slope B on the above graph.