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Bad Power can be a Big Problem

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November 01, 2009
Electric Power
Geoff Griswold - theomnigroup@mindspring.com

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© 2009 Hospitality Upgrade. No reproduction without written permission.

Many managers and even some ITfolks may not be fully aware of the issues undependable electric power can cause with high-tech equipment.

While most of us take electricity for granted except when there is a long power outage, the quality and consistency of electric power can have a large impact on the performance of technology equipment.  This is especially important to those devices that use some type of memory configuration. 

Almost all hotels receive power from a local power company that is transmitted over power lines (www.howstuffworks.com).   Power companies have a series of electrical generators that can be powered in a number of different ways.  Hydro-electric plants harness the power of rushing water to spin the wheels of the generators.  A diesel engine or gas turbine can also be used.  The most prevalent way to generate power is with a steam turbine that can be fired with natural gas, coal or oil.  A nuclear power plant uses a reactor to heat steam turbines.

Power plants produce what is called three phase power.  They are produced simultaneously and are offset 120 degrees from each other.  The current produced is alternating (AC) meaning it can be reversed, positive to negative.  Power produced by generators enter a transmission substation near the power plant.  The voltage is then amplified to very high levels for long distance transmission.

The power grid is a system of interconnecting transmission lines, broken down into the transmission grid and the distribution grid (see below). Main transmission lines have four wires, one each for each phase of electricity, and one for a ground wire.  The ground wire is mainly used to attract and ground lightning strikes.

Power over transmission lines is between 150,000 and 750,000 volts.  Obviously, this level of voltage would destroy any piece of high tech equipment, but it is reduced significantly as the power is converted from “transmission” to “distribution” in a power substation through a transformer.  This conversion lowers the voltage to fewer than 9,000 volts.

From there, transformer drums, visible on power poles, or buried under the ground if underground cables are used, step down the power to 240 volts.  These drums occasionally malfunction and rupture, causing a sound similar to a cannon shot.
There are several power conditions or “power events” (APC Web site www.apc.com) that can occur that will affect the condition of high tech equipment.  A brownout or sag occurs when the voltage level of the power drops enough to affect the operation of equipment.  This can occur when there are many motors, elevators, kitchen equipment, etc. used in the hotel simultaneously.  They are also caused by the power company using “rolling brownouts” to control demand during peak cooling season.

Total blackouts can be caused by an accidental downed power pole, excessive demand along the power grid, storms, ice on power lines, and other natural disasters.
In the case of total blackouts, many hotels have emergency generators that activate automatically.  In situations where the generator(s) do not cover the entire hotel, all high tech equipment should be on the generator(s), especially server rooms, telephone equipment, PMS and the POS.

Power spikes are the reverse of power brownouts.  Spikes are a dramatic increase in voltage.  The main cause of spikes are lightning strikes and when power comes back online from a blackout.  Spikes can seriously damage any type of equipment, but especially high-tech gear.

Computers, routers, DSL modems, smart switched hubs all have settings stored in some type of memory such as a BIOS or other types of storage.  Power conditions can alter these settings to the point that the device will not function properly, even though the device still appears to be operating.  For example, after a power spike a network router can revert to the factory settings, which may not be correct for that network’s configuration.  Even though the router is still operating, the settings will have to be corrected for it to function properly on that particular network.

It is important to have on file the settings of all routers, switched hubs and DSL modems used in the hotel.  These settings should be printed out and stored in a safe place.

The need for proper power protection cannot be overemphasized.  Surge protection is a must for all high tech equipment, with backup power supplies (UPS) installed on the most critical equipment.

A good surge protector can be purchased for as little as $10.  The device can detect voltage above a certain level and divert the excess to the outlet’s grounding wire.
A UPS (uninterrupted power supply) contains batteries that feed current through an inverter (converts DC power to AC power) if the power goes down.  UPS have a volt/amperage rating.  It is important that devices attached to the UPS fall below the VA rating.  In other words, the UPS has sufficient capacity to support the devices should the power fail.

Geoff Griswold is a hardware and wiring specialist for The Omni Group. He can be reached at (888) 960-8787 or theomnigroup@mindspring.com.

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