PCE UPS SYSTEMS Inc. is an advanced uninterruptible power system (UPS) consisting of a battery source, a converter, and control equipment. Its main purpose is to prevent spikes, surges, sags, transients and blackout from damaging your equipment and data.
When AC power is present, UPS continuously filters small fluctuations. And when AC power fails, it employs its internal maintenance-free battery to supply backup power without interruption.
There are two classifications of UPS - Rotary and Static
A rotary UPS is a generator converting fuels into electrical energy.
A static UPS uses an electronic inverter to convert chemical energy in battery into electrical energy.
Power quality can be worse than ever in certain areas of the world. Problems such as blackouts, brownouts, surges and noises are happening with increased frequency. According to a study, conducted by Bell Labs, blackouts have increased by 150% since 1972. Further, IBM says that a typical computer is subjected to more than 120 power problems per month. The effects from power problems range from subtle keyboard lockups and minor system crashes-to the dramatic-complete data loss or permanent hardware damage. And most of these problems can be avoided with the use of a good quality UPS.
A UPS traditionally can perform the following functions:
- Absorb relatively small power surges.
- Smooth out noisy power sources.
- Continue to provide power to equipment during line sags.
- Provide power for some time after a blackout has occurred.
In addition, some UPS or UPS/software combinations provide the following functions:
- Automatic shutdown of equipment during long power outages.
- Monitoring and logging of the status of the power supply.
- Display the Voltage/Current draw of the equipment.
- Restart equipment after a long power outage.
- Display the voltage currently on the line.
- Provide alarms on certain error conditions.
- This is the topology used by PCE Yuppie and IP series. The AC line is the primary power source. The battery/inverter circuitry supplies the load in case of a power failure for fluctuation. Any drop in the voltage or current is detected by the UPS, which automatically switches the battery into the circuit, cutting of the main power line-thus allowing the battery to supply the required power. The transfer time should not take more than 4 milliseconds, as this is the tolerance limit of a typical computer power unit.
- This is the topology used by the PCE UPS XP, and SP series. The AC line power is the primary source and is being constantly filtered. In case of a brownout condition the automatic voltage regulation circuitry is activated to correct the problem. The battery and inverter circuitry supplies the backup power in case of a blackout
- This is the topology used by the PCE UPS VPM, Modu6,Modu8, HP, and NP series. This UPS operates with the inverter as the primary power source supplying the load and therefore there is no transfer time in case of power failure. This type of "on-line" power eliminates any interruptions in the flow of electricity. And since it uses more electronic wizardry than offline UPS, it is priced higher. Besides the higher price, on-line UPS also has the disadvantage of high running costs and temperature. Since the battery acts as the primary power source to the system, an on-line UPS battery charger has to be powerful enough to generate enough power to compensate for the battery's power drain. This conversion from AC mains to DC for the battery and back to AC through the inverter results in a 25 to 30 percent power loss. The heat generated as a consequence of the power loss shortens the life of electrical components and reduces battery life.
Connected equipment category
- Resister Load:
- Capacity Load:
(95% of electric equipment belongs to this kind of load)
PC, Monitor, TV
- Inductor Load:
Equipments should run on the best approximation of sinusoidal input, as deviations produce harmonics which may either be interpreted as signal if they get through a power supply, or may actually damage the equipment. UPS output waveform can be either pure sinewave or simulated sinewave. Choosing the UPS output wave depends on the load type:
- Pure Sinewave output is required only for inductive load like motors, water pumps and fans.
- Computers and monitors are quite satisfied with approximated sinewave since almost all computers use switching-type power supplies, which only draw power at or near the peaks of the waveforms, in this case, the shape of the input power waveform is not important.
Using a simulated sinewave for inductive load will generate some noise and heat.
Besides choosing a UPS design, there are 2 key ratings to be aware of when choosing a UPS unit. The first is the volt amp (VA) and power (watt) ratings. Both the ratings represent the maximum amount of load that the UPS can support and the connected load typically should not exceed 80% of either. Special considerations must be made when connecting certain equipment such as printers or any type of motorized load. The second factor in deciding which unit to purchase is the amount of runtime the unit will be able to provide when the power fails. This number will vary with the load amount that is plugged into the UPS. For example, a unit may run a single computer for 30 minutes, but with 2 computers it may only last half that time or less. Larger units typically can provide more runtime for the same load than smaller units, however that is not always the case. Some UPS units are designed to provide extended runtime or have the ability to have external battery packs connected such as our long back up models (SPL,VPML,etc..).
Another consideration is the anticipated usage. If the UPS is only intended to provide enough power to gracefully shut down the computers, serial or USB ports on the UPS and support software are essential. If the purpose of the UPS is to provide power until a standby generator kicks in (typically under a minute), the UPS input capabilities should be matched to the generator outputs so as to handle frequency fluctuations well. A UPS with a wide "frequency window" is essential is such cases.