How to Use Virtual Desktops in Windows 10...???

Virtual desktops were finally added as a built-in feature in Windows 10. If you’ve used Linux or Mac, you know this can be a very useful feature. If you open a lot of programs at once, this feature allows you to keep them organized.

The virtual desktops feature in Windows 10 is called “Task View” and is located on the Taskbar.

Clicking the “Task View” button brings up the Task View interface, where you can see your open windows on virtual desktops you’ve added. When you open the Task View interface for the first time, or you only have one desktop, the “Add a desktop” button is available. Click it to add another virtual desktop.

Now, when you click the “Task View” button, all your desktops display on the Task View interface. In the example below, there are no windows open on either of the desktops.

If you have program windows open on your desktops, they show on the thumbnails of the desktops on the Task View interface. When you move your mouse over a desktop on the Task View interface, the open programs on that desktop display as large thumbnails above the Task View interface. Click on one of the large thumbnails to make that program (and the corresponding desktop) active. It’s similar to the old Alt + Tab feature from previous versions of Windows. Click on a desktop on the Task View interface to make that desktop active.

You can switch desktops using the keyboard, as well. To do this, press the Windows key + Tab. The programs on the currently active desktop display as large thumbnails, as discusses above and the thumbnail for the currently active program on that desktop is outlined. Now, press Tab again. This removes the outline from the active program thumbnail and Task View interface active. Use the arrow keys to move among the desktops on the Task View interface. When you have highlighted the desktop to which you want to switch, press Enter.

Windows indicates when a program is open on other desktop be putting a line under that program’s icon on the Taskbar. Clicking the icon not only activates the program, but also the desktop on which it is open.

You can move programs among the different desktops you’ve set up. To do so, switch to the desktop containing the program you want to move. Click the “Task View” button on the Taskbar. Right-click on the large thumbnail for the program you want to move, select “Move to,” and then select the desktop number to which you want to move the program.

The program now displays on the other desktop.

To close a desktop, click the “Task View” button on the Taskbar to bring up the Task View interface. Move your mouse over the thumbnail for the desktop you want to close. Click the X button that displays in the upper-right corner of the thumbnail.

NOTE: If you close a desktop that has open programs on it, those programs are transferred to the next desktop to the left of the one you’re closing.

If you’re using a touch screen computer or device, you can access the Task View, or virtual desktops, by swiping in from the left. This feature replaces the old application switcher for both touch and non-touch screen devices.

What are the Causes of Poor Power Factor ???

                       Induction motors are a prime cause of low power factor for many customers. Poor power factor is an issue especially for customers with large numbers of small fractional horsepower motors, those who purchase cheap or poorly made motors, and those having oversized, under-loaded motors.

            Most small fractional horsepower motors have low power factors in the 50 to 60 percent range. As the rated horsepower of the motor increases, in general, the power factor of the motor at full load increases. Therefore, larger horsepower motors have better power factors than small horsepower motors if each motor is properly loaded.

          Power factor may vary significantly between two motors of the same size made by different manufacturers. It is important to select motors from reputable manufacturers and consider the power factor ratings of the individual motors. Generally, if a motor has a high power factor, it is constructed of better materials, will last longer, and may have a longer warranty.

          Under loaded or extremely lightly loaded motors are a prime cause of low power factor in many installations. Power factor varies significantly with motor load. This figure illustrates how power factor is affected by the total loading of a typical motor. The power factor is near its maximum at the motor's rated load. The power factor falls significantly if the motor is only partially loaded. Installations may still exhibit low power factors even though they have high power factor motors when the motors are only partially loaded.

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Active, Reactive, Apparent and Complex Power. Simple explanation with formulas ...

Real Power: (P)

 Alternative words used for Real Power (Actual Power, True Power, Watt-full Power, Useful Power, Real Power, and Active Power)

In a DC Circuit, power supply to the DC load is simply the product of Voltage across the load and Current flowing through it i.e., P = V I. because in DC Circuits, there is no concept of phase angle between current and voltage. In other words, there is no Power factor in DC Circuits.

But the situation is Sinusoidal or AC Circuits is more complex because of phase difference between Current and Voltage. Therefore average value of power (Real Power) is P = VI Cosθ is in fact supplied to the load.

In AC circuits, When circuit is pure resistive, then the same formula used for power as used in DC as P = V I. 

You may also read about Power Formulas in DC, AC Single Phase and and AC Three Phase Circuits.

Real Power formulas:

P = V I                                  (In DC circuits)

P = VI Cosθ                          (in Single phase AC Circuits)

P = √3 V_L I_L Cosθ         or     (in Three Phase AC Circuits)

P = 3 V_Ph I_Ph Cosθ 

P = √ (S² – Q²)^or

P =√ (VA² – VAR²) or  

Real or True power = √ (Apparent Power²– Reactive Power²) or

kW = √ (kVA² – kVAR²)

Reactive Power: (Q)  

Also known as (Use-less Power, Watt less Power)

The powers that continuously bounce back and forth between source and load is known as reactive Power (Q)

Power merely absorbed and returned in load due to its reactive properties is referred to as reactive power

The unit of Active or Real power is Watt where 1W = 1V x 1 A.

Reactive power represent that the energy is first stored and then released in the form of magnetic field or electrostatic field in case of inductor and capacitor respectively.

Reactive power is given by Q = V I Sinθ which can be positive (+ve) for inductive, negative (-Ve) for capacitive load.

The unit of reactive power is Volt-Ampere reactive. I.e. VAR where 1 VAR = 1V x 1A.

In more simple words, in Inductor or Capacitor, how much magnetic or electric field made by 1A x 1V is called the unit of reactive power.

Reactive power formulas:

Q = V I Sinθ

Reactive Power=√ (Apparent Power²– True power²)

VAR =√ (VA² – P²)

kVAR = √ (kVA² – kW²)

Apparent Power: (S)

The product of voltage and current if and only if the phase angle differences between current and voltage are ignored.

Total power in an AC circuit, both dissipated and absorbed/returned is referred to asapparent power

The combination of reactive power and true power is called apparent power

In an AC circuit, the product of the r.m.s voltage and the r.m.s current is called apparent power.

It is the product of Voltage and Current without phase angle

The unit of Apparent power (S) VA i.e. 1VA = 1V x 1A.

When the circuit is pure resistive, then apparent power is equal to real or true power, but in inductive or capacitive circuit, (when Reactances exist) then apparent power is greater than real or true power. 

Apparent power formulas:

S = V I

Apparent Power = √ (True power² + Reactive Power²)

kVA = √kW² + kVAR²

Note ;

Resistor absorbs the real power and dissipates in the form of heat and light.

Inductor absorbs the reactive power and dissipates in the form of magnetic field

Capacitor absorbs the reactive power and dissipates in the form of electric or electrostatic filed

                        

Why Power Plant Capacity Rated in MW and not in MVA ???

For the following reasons, a Power plant capacity rating may be expressed in MW instead of MVA.

In a Generating station, the prime mover (Turbine) generates only and only Active Power. That’s why we rated a power plant capacity in MW instead of MVA. Its mean no matter how large your generator is, but it depends on the capacity of the  engine (Prime mover/Turbine) I.e. a 50MW turbine connected to a 90MVA alternator in a power plant will generate only 50MW at full load. In short, a power plant rating is specified in terms of prime mover /Turbine (Turbine rating may be seen by nameplate rating which is in MW or Horsepower (HP) not in MVA) and not by the alternator set coupled to it.

Another thing is that, electric power company charges their consumer for kVA while they generate kW (or MW) at the power station (Power plant).They penalize their consumer for low Power factor because they are not responsible for low power factor and kVA but you. Moreover, in power plant, power factor is 1 therefore MW is equal to MVA …… (MW = MVA x P.f).