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Showing posts with label data-center. Show all posts
Showing posts with label data-center. Show all posts

Watt and Volt-Amp (VA) Rating Notes

1. Definition and Purpose

  • Watt is the real power drawn by the equipment.  The Watt rating to determine the actual power purchased from the utility company and the heat loading generated by the equipment.
  • The VA rating is used for sizing wiring and circuit breakers.

2. IT Equipment Switching Power Supply Types

  • Power Factor Corrected supply (PFC)
  • Capacitor Input supply

3. Computer Equipment Watt and VA Rating

  • Large computer equipment such as routers, switches, arrays, and servers made after 1996 use the PFC supply. Watt rating = VA rating
  • PCs, small hubs, PC accessories, and larger computer equipment made prior to 1996 typically use Capacitor Input supply. Watt rating = 0.55 ~ 0.75 * VA rating

4. UPS Watt an VA Rating

  • Small UPS: Watt rating = 60% * VA rating (a de-facto standard in the industry)
  • Larger UPS: Watt rating = VA rating

5. Conclusion

  • Neither the Watt nor the VA rating of a UPS may be exceeded
  • Sizing the VA rating of a load to be no greater than 60% of the VA rating of the UPS ensures the Watt rating of a load not to exceed the Watt rating of the UPS.  This conservative sizing approach will typically oversize the UPS and provide additional run time.

Source: APC White Paper #15 “Watts and Volt-Amps: Powerful Confusion”

Use WinSCP to Transfer Files in vCSA 6.7

This is a quick update on my previous post “ Use WinSCP to Transfer Files in vCSA 6.5 ”. When I try the same SFTP server setting in vCSA 6.7...