UPS (uninterruptible power supply system) Part03

Uninterruptible Power System

TOPAZ POWER MAKER

THEORY OF OPERATION 

1- GENERAL

The Topaz Power maker Mini is an uninterruptible power system (UPS) that is installed between the utility AC line and the critical load. It can be operated either as an on-line, bypass mode UPS. The primary function of a UPS is to maintain a regulated output to a critical load regardless of blackout or brownout conditions.

The Topaz Power maker Mini is an uninterruptible AC power source that connects to an AC power line between the utility power source and the equipment to be protected. It includes batteries, a rectifier/battery charger, an inverter, a static transfer switch, and an isolation transformer with a transient suppresser and filter network.

The Topaz Power maker Mini can be operated as either a bypass (off-line) type or an on-line type of UPS. In bypass operation, under normal conditions when utility power is available, the battery charger keeps the batteries fully charged while the load is powered by the utility line through the isolation transformer. If the utility line voltage should drop below 85% of its nominal value, the load is switched to the inverter which, powered by the battery, immediately begins delivering AC power to the critical load with no discernible interruption. When the utility AC line voltage returns to approximately 90% of its normal value, the load is switched back to the output of the isolation trans­former and the inverter shuts off.

In on-line operation, the load is powered by the inverter, which operates continuously, drawing power either from the utility AC line through the rectifier or, if the AC line voltage drops too low from the battery. When the AC line voltage is present, the battery charger keeps the batteries charged.

The user selected bypass mode of operation has advantages in that it provides full protection against power failures while maximising system efficiency and reliability as well as minimising operating costs, audible noise and heat dissipation.

2- TERMINOLOGY

The following terms are frequently used in describing UPS operations:

1.Backup Time The duration of time that a UPS is specified to maintain output voltage after a blackout (typically specified at full load and half load).

The backup time provided by fully-charge d batteries will vary depending on the rating of the UPS and the magnitude of the load. However, at least 10 minute of backup time at full rated load is provided in all cases. This is more than adequate for an orderly shutdown of the load. If more backup external batteries may be connected to the system.

2-Bypass Line - The AC input line that is arranged to be used as an alternative to the UPS Inverter as a source of power. In the Topaz Power maker Mini, it is isolated and filtered to provide noise free power to the load.

3-Bypass Mode -A mode of UPS operation during which the load is connected to the bypass line. in the Topaz Power maker Mini, the load voltage is continuously monitored during this mode of operation, and the Inverter can promptly become active and maintain power. to the critical load. Better efficiency and reliability is inherent in the by bypass mode of operation

4-On-line Mode‑A mode of UPS operation during which the load is continuously supplied by the UPS inverter.

5-The inverter receives power either from the AC line through the rectifieror, should the AC line fail, from the battery.

6-Transfer The process of changing the source of load power from the inverter to the bypass line or vice versa.

7-Efficiency - Power delivered to the load by the UPS, divided by the power delivered by the AC line (usually expressed as a percent).

 

3- BATTERIES

Batteries are shipped separate from the UPS to ensure safe transport of the equipment and to en­sure that the user receives fully-charged batteries.

They are assembled in the battery trays and inter connected ready to be installed in the UPS by the user. The 3 kVA and 5 kVA ratings each have two battery trays; the 10 kVA rating has four trays. Batteries are lead-acid, maintenance free type.