UPS Calculation and Diversity Factor

As you state 50Hz supply I guess you are in the UK, so please find a copy of the electrical regs and study..... also as you are a student, you may want to wait until the subject is covered in the next lecture, but until then here is a few pointers for you...

Diversity describes the situation in an electrical installation in which (1) not all loads connected to the system are operating simultaneously, or (2) loads are not simultaneously operating at the maximum rating. Diversity is used when determining the current loading on an electrical system in order to determine appropriate conductor sizes.

Allowable diversities are usually specified in the relevant electrical code or wiring regulations. For example, the 'On-Site Guide' supplement to the UK's BS 7671:2008 Wiring Regulations specifies how demand is to be determined for a household cooking appliance (range) as follows:

"The first 10 A of the rated current, plus 30% of the remainder of the rated current, plus 5 A if a socket outlet is incorporated in the control unit."

Also.......to help remove your confusion!!

A volt-ampere (VA) is the unit used for the apparent power in an electrical circuit, equal to the product of root-mean-square (RMS) voltage and RMS current.[1] In direct current (DC) circuits, this product is equal to the real power (active power) in watts. Volt-amperes are useful only in the context of alternating current (AC) circuits (sinusoidal voltages and currents of the same frequency).

KVA

Apparent power is the vector sum of real (P) and reactive (jQ) AC power vectors While both the volt-ampere (abbreviated VA) and the watt have the dimension of power (time rate of energy), they do not have the same meaning. Some devices, including Uninterruptible Power Supplies (UPSs), have ratings both for maximum VAs and maximum watts.

The VA rating is limited by the maximum permissible current, and the watt rating by the power-handling capacity of the device. When a UPS powers equipment which presents a reactive load with a low power factor (e.g., a computer), neither limit may safely be exceeded.

Kilowatt

The kilowatt is equal to one thousand (103) watts. This unit is typically used to express the output power of engines and the power consumption of electric motors, tools, machines, and heaters. It is also a common unit used to express the electromagnetic power output of broadcast radio and television transmitters.

One kilowatt of power is approximately equal to 1.34 horsepower. A small electric heater with one heating element can use 1.0 kilowatt. The average annual electrical energy consumption of a household in the United States is about 8,900 kilowatt-hours (cf the average UK household's approx 4,700 kilowatt-hours for example), equivalent to a steady power consumption of about 1 kW for an entire year.[4] Also, kilowatts of light power can be measured in the output pulses of some lasers.

Confusion of watts, watt-hours, and watts per hour

The terms power and energy are frequently confused. Power is the rate at which energy is generated or consumed.

For example, when a light bulb with a power rating of 100W is turned on for one hour, the energy used is 100 watt-hours (W•h), 0.1 kilowatt-hour, or 360 kJ. This same amount of energy would light a 40-watt bulb for 2.5 hours, or a 50-watt bulb for 2 hours. A power station would be rated in multiples of watts, but its annual energy sales would be in multiples of watt-hours. A kilowatt-hour is the amount of energy equivalent to a steady power of 1 kilowatt running for 1 hour, or 3.6 MJ. Terms such as watts per hour are often misused.[15] Watts per hour properly refers to the change of power per hour. Watts per hour (W/h) might be useful to characterize the ramp-up behavior of power plants. For example, a power plant that reaches a power output of 1 MW from 0 MW in 15 minutes has a ramp-up rate of 4 MW/h. Hydroelectric power plants have a very high ramp-up rate, which makes them particularly useful in peak load and emergency situations.

Major energy production or consumption is often expressed as terawatt-hours for a given period that is often a calendar year or financial year. One terawatt-hour is equal to a sustained power of approximately 114 megawatts for a period of one year.

The ampere (symbol: A) is the SI unit of electric current (symbol: I) and is one of the seven SI base units. It is named after André-Marie Ampère (1775-1836), French mathematician and physicist, considered the father of electrodynamics. In practice, its name is often shortened to amp.

In practical terms, the ampere is a measure of the amount of electric charge passing a point per unit time. Around 6.241 × 10(18) electrons, or one coulomb, passing a given point each second constitutes one ampere.

Thanks given to Wikipedia.... side question, do they not teach students how do do "research" these days??