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 | Dual Conversion On-line Static |
| Line Interactive or Off-line |
Dual conversion: The UPS rectifier makes full power DC and inverts the DC to a new clean AC output waveform. For Dual Conversion we recommend Toshiba as the leader in this manufacturing segment. The technology Toshiba utilizes is considered state-of-the-art. Specific items considered in this analysis are 1) tighter output waveforms with lower distortion, 2) virtually no voltage sag even with 100% step loading, 3) transistorized rectifiers to match the needs of inverters to minimize battery use and extend battery life and 4) inherently low input distortion without adding efficiency robbing input filters and 5) Toshiba UPS is American made for sizes from 1 kVA to 300 kVA. Standard warranty of Toshiba UPS is three years. This industry has seen three of the four manufacturers strive for lowest cost producer status by using 1980s technology hidden by updated displays. Of the four major UPS manufacturers only Toshiba has been developing new state of the art technology for this market. This market is highly developed and pricing among the major manufacturers is generally within a 10% range despite the lowest cost producer goals. Given the tightness of industry prices we believe the best technologies should be implemented. Total ownership costs generally will be lower with the newer technology offered by Toshiba.
Line interactive: The UPS buffers utility power. It does not generate a new assured clean power output to the critical load. Manufacturers include APC, Tripplite and many others. We believe this technology use should be limited to home computers and non-critical business application. Although the technology is offered for three phase products the apparent cost savings of selecting line interactive technology is lost through lower protection levels and harder battery use (more frequent battery replacements required). Generally office supply stores and computer stores are the lowest cost source for line interactive UPS which is a commodity product. As our company specializes in more critical applications we generally do not provide line interactive UPS. Be aware that due to the lower quality reputation of line interactive UPS, manufacturers of this technology go to great lengths to state or infer their offering is not line interactive. Ask what action the UPS takes if utility or generator frequency sags 5% (3 HZ). If the unit switches to battery support it is line interactive.
Link to: Battery UPS Data, UPS Technical Articles
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Site Update 03/26/08 |