**TECHNICAL TERMS DEFINED**

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__1 kHz Forward Transfer Impedance__ “Lower is Better”

Computer and similar power supply electronic loads are really AC to DC converter loads. All AC to DC converters draw current in a single pulse during each half cycle of the 60 cycle sine wave. This pulse of current does not resemble the 60Hz sine wave at all. If the average (RMS) current value is 5 amps, the peak of each current pulse may be 20 amps. Also, these current pulses have substantial frequency components in the area of 1 kHz. (The basic repetition frequency of these pulses is still 60 Hz, but the shape of the pulse while it is transferring energy contains the 1 kHz frequencies.) If a power conditioner is to deliver energy to the converter it must transfer this energy from the utility company (wall socket) to the load as efficiently as possible. Any impedance in the power conditioner at the 1 kHz frequency will impede that transfer.

__Distortion__ “Lower is Better”

This is a measure of the change in the waveform introduced by the power conditioner or UPS. Ideally, the output waveform should exactly match the input wavform, a distortion of 0%. ONEAC products introduce less than 1% THD (total harmonic distortion) when measured with a resistive load.

__Efficiency__ “Higher is Better”

Energy wasted as heat or audible noise reduces efficiency from the ideal of 100%. No electronic equipment is 100% efficient, but some can get very close. The cost of this wasted energy can be calculated and used to justify the higher cost of a more efficient unit.

For example, assume that energy costs 7¢/kilowatt-hour and a 10kVA unit is being considered. At 90% efficiency, 10% or 1kVA is being wasted. 1kVA x .07/kilowatt-hour x 24 hours/day x 365 days/year = $613.20/year Increasing the efficiency to 95% will reduce the wasted energy to 5% or ½kVA. ½kVA x .07/kilowatt-hour x 24 hours/day x 365 days/year = $306.60/year.

__Inrush and Surge Current Rating__ “Higher is Better”

Electronic loads generally draw several times steady state current immediately after they are turned on. During the 1st ½ cycle of operation, many loads require an inrush of current up to 20 times their steady state current. A surge current is then drawn that falls off to the steady state value during the following several cycles up to several hundred cycles, depending on the characteristics of the load. (For example, rotating machinery such as pumps and large disc drive motors tend to draw significant current for several seconds as the motor comes up to speed.) The inrush rating specifies the peak current that can be delivered to the load during the 1st ½ cycle. The surge current rating specifies the maximum RMS current that can be delivered to the load during the following 1 second (60 cycles) and 5 seconds (300 cycles). These current levels are available at any time during system operation. If these ratings are exceeded, the unit's circuit breaker will turn the unit off with no adverse effects.

__Load Current Rating__

The maximum steady state RMS current that can be supplied to the load. Operation up to this rating is both safe and reliable; oversizing is NOT required. If the unit is overloaded, the circuit breaker will turn the unit off with no adverse effects. Drawing less than the rated current has no effect on performance.

__Load Power Factor__ “Wider **Range is Better”**

Power factor is a measure of how a piece of equipment uses electrical power. A pure resistive load has a power factor of 1.0 and will not stretch the capabilities of a power conditioner or UPS. A power factor of .5 leading or .5 lagging can severely strain some power conditioners or UPS systems. ONEAC systems can handle a range of from .3 leading to .3 lagging.

__Load Regulation__ “Lower is Better”

The average (RMS) output voltage of a power conditioner will usually change with a large change in the load. This specification promises that the power conditioner output will change by no more than the stated % when a resistive load suddenly changes from 10% to 100% of the rated load.

__Load Regulation Response Time__ “Lower is Better”

For a power conditioner or UPS to not distort the output sine wave it must respond rapidly to changes in the load and its response must not create any additional electrical noise. A response time of 2 msec to a change in the load of 50% is fast enough for almost all applications. Furthermore, the ONEAC output will not overshoot or undershoot as a result of the load change.