In a recently pubished Whitepaper Uninterruptible Power Supplies Ltd (UPSL Ltd,) a Kohler Company provides not only valuable insights on the upsides and downsides of dual bus power. (Download here), in this paper we also find an infographic that we want to share with you. It shows the differences in efficiency, at all loads, between a legacy North American machine and an IGBT/IGBT transformer-less UPS design:
As you can see, modern UPS designs have daramatically improved in recent years, and the change in part load efficiency of static UPS has also overtaken that of rotary UPS in all ist variants.
Therefore, the authors of the white paper give the following advice:
- Use high-efficiency IGBT/IGBT transformer-free UPS that has high partial load efficiency
- Apply it in a scalable way that suits the anticipated initial load and anticipated load growth profile – with the aim of maintaining as high a system load as is possible by turning ‘off’ any over-redundant capacity.
- In one (or even both) bus turn ‘on’ the UPS’s eco-mode capability and virtually halve the system losses (ability to start the UPS inverter in static bypass if mode conditions dictate)
- Try to restrict the installed battery capacity on each module to under 10 minutes.