Uninterruptible Power System 800 Guía de instalación descargar pdf (Pagina 20)

PROPERTY OF SOLIDSTATE CONTROLS, INC. 7/1998

2. Ventilation

All stationary batteries produce hydrogen gas while they are being charged. Gassing does not

become a problem until approximately 70% of the charge has been returned to the cells. The

battery room must have adequate ventilation, preferably to the outside, to prevent the build-up

of hydrogen gas in the room.

The size of the room and the size of the battery bank will determine the amount of ventilation

required. As a general rule, ventilation should be adequate to provide from one to four air

exchanges per hour.

Batteries do not gas when they are being discharged, only when they are being charged.

Consequently, loss of ventilation during a power outage is not a problem, unless a critical

operating temperature is reached in the room as a result.

The end voltage is the minimum voltage that the cell will be allowed to reach during discharge. In

general, with lead acid batteries, it is recommended that the per cell end voltage not be allowed to

go below 1.75 volts per cell for long-term discharge batteries (those over 60 minutes), and 1.67

volts per cell for short-term discharge batteries (those 60 minutes and below). The UPS DC voltage

windows will also need to be compatible and should first be consulted. This is necessary to prevent

possible damage to the batteries. To accomplish this, the UPS should be equipped with a low DC

disconnect feature to disconnect the UPS from battery when this level is reached.

This is a standard factor on all UPS systems, but if not, this feature should be requested.

Batteries can provide many years of safe, reliable service. However, the use and handling of batteries

does pose some hazard, unless safety precautions are exercised. Before removing batteries from the

pallet, the customer must read and become familiar with the personal safety precautions regarding

battery handling. In addition, since batteries can be damaged due to incorrect handling, the customer

should also read all the general equipment precautions and handling instructions.

Briefly, be aware that batteries can contain residual gas in the cells, even during shipping. Do not

smoke or otherwise introduce flames, sparks or other potential sources of ignition into the battery area.

Batteries are usually shipped wet, filled with sulfuric acid electrolyte for lead acid types or potassium

hydroxide for nickel cadmium types. Both are caustic. Be careful to keep them upright at all times.

Batteries can supply very high short circuit currents. Remove all rings and jewelry. Use only insulated

tools. Keep all metal tools or metal parts which could be dropped across the battery terminals away

from the batteries.

Before stationary batteries are installed, the battery room should be equipped with an emergency eye

wash and the customer should become familiar with its operation. He should also have available full

eye protection, rubber gloves, and apron to protect eyes and skin from contact with the sulfuric acid

electrolyte. These items can be ordered with the battery, or the customer can order from his preferred

source and have available before the batteries arrive.

For further information regarding batteries, refer to Selection and Sizing of Batteries for UPS Back-

up, by Kenneth E. Eppich, Sales Engineer.

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Uninterruptible Power System 800 Guía de instalación Pagina 20