CrossNodes Checklist: You've Got the Power!

By Elizabeth Ferrarini | Nov 7, 2001 | Print this Page
http://www.enterprisenetworkingplanet.com/netsysm/article.php/919051/CrossNodes-Checklist-Youve-Got-the-Power.htm

Depending on its severity, any type of a power outage can wreak havoc with just one server or a building. This type of disruption can impair security systems, damage equipment, and lose data. An Uninterruptible Power Supply (UPS), on the other hand, can ensure a steady flow of power during the time the traditional electric power source isn't operational.

Each of the three types of UPS's handles a specific type of power outage. A standby UPS guards against brownouts and blackouts by pulling power form the battery. A line-interactive UPS provides battery power during blackouts and protects against surges and brownouts with an inverter for automatic voltage regulation. An online UPS isolates equipment from any type of a power disturbance by converting incoming back from AC to DC and then back to AC before exiting the UPS.

The following checklist provides what you should look for in each one of the UPS types, how to determine your overall costs, what questions you should ask potential vendors, what questions you need to ask vendors' customers, what points you better double check, and how you can make sure you don't get a shock.

What you should look for
First of all, look for vendors with engineering capabilities to meet your special needs. They should provide around-the-clock field service and should be able to respond to any emergency you might have. Definitely look for products with the UL certification in the United States, CSA in Canada, and CE and TUV in Europe. Consider the capabilities of the management software that comes with the UPS. Does the software provide you with the status of the UPS or page you if there is a power outage? Note the capabilities of the battery management system, which will increase the battery life and run time. Also look for adjustable option switches that allow you to tailor voltage transfer levels to site specifications, disable alarms, and change low battery warning settings.

Other features to consider include the following: Warning methods, such as paging and network broadcast message, which you can tailor. Site fault indicators and front-panel indicators, including low battery, replace battery, and load meter.

  • Communications that fit user applications, such as RS-232 and contact closures.
  • Tight output voltage regulation.
  • Ability to correct for surges and sags.
  • Superior noise attenuation addressing load and line-generated harmonics.
  • Versatile and sufficient output connections.
  • Unattended shutdown software and bypass system.
  • Magnetic isolation.
  • Optional run-time availability and sine wave output to battery.

Cost Considerations

  • You can uncover any hidden costs by doing a detailed analysis of all your costs. Some of the things to consider include:
  • Prices for UPS's depend on what type you're purchasing. For example, a single-station UPS, which provides five to 10 minutes of backup power, can cost between $100 to $200. A UPS with extended run time can cost from $800 to $2,000. An online UPS can cost up to 20 percent more for comparable sizes.
  • Consider the cost advantages of buying a UPS that comes loaded with a lot of features versus the cost of adding features to a less expensive model.
  • Determine if purchase price includes the installation, as well as any management software.

What information should you be prepared to give vendors?
To bid for your business, vendors will want to know as much as possible about your network environment. Be prepared to provide them with the following information:

  • Specific application, installation location - office, data center, or industrial.
  • Input/output voltage requirements and KVA rating.
  • Battery time desired.
  • Look at your load requirements. What equipment will the UPS support and how much power will it need to draw? You can find this information on equipment labels. Also examine the mission critical load priorities.
  • Obtain the aggregate electrical load by taking ammeter readings of electrical distribution boxes at peak operating times, from listings on electrical distribution boxes, or as peak demand readings on your electrical bill.

What questions should you ask potential vendors?

  • What's the unit's time, and voltage range?
  • Does the unit include visual and audible alarms, and have battery capabilities?
  • Is noise filtering technology used?
  • Is the UPS compatible with power management software, as well as compatible with a UPS generator?
  • Do you have a battery and preventative maintenance program?
  • Do you employ factor-training field service engineers?
  • Do you offer dedicated service?
  • Has the unit met IEEE 587 or IEC 664 test requirements for surge suppression?
  • Does the unit include a modem, a fax, and some type of network protection to safeguard against surges coming through phone lines or network data lines?
  • Will you repair or replace equipment damaged due to a UPS malfunction?
  • What are the specifics of your warranty and or extended warranty?

What questions should you ask the vendor references?

  • Did the vendor deliver the unit on time to you?
  • Did the installation go smoothly?
  • Are you satisfied with performance, service?
  • What are the products strengths and or weaknesses?
  • Did you have any problems with activating the unit? Results?
  • Describe your experiences testing the devices? Results?
  • Why did you select the vendor and the particular device? What other vendors' devices did you consist?
  • What did your selection process entail?
  • Did you get a good deal or were you sold a bill or goods?

What things should you double check?

  • A UPS should supply the load with an ideal sine wave or stepped wave output. Square sine waves can damage loads or cause malfunctions.
  • Determine the transfer time when switching to battery power. Although most UPS's have transfer times of two milliseconds or less, transfer time of even half a second can cause computer failure.
  • If you're getting extended battery run time, make sure you're not over-buying in terms of kVA.
  • Don't mistake TVSS surge suppression for power conditioning.

What steps should you take before you seal the deal?

  • Involve the appropriate operations and facilities management personnel in equipment evaluation and selection.
  • Create a features matrix accounting for all possible offering, for at-a-glance comparison of all models being considered.
  • Once you have narrowed your choices, get a demonstration of each unit.