STATIC RELAYS

A static relay refers to a relay in which there is no armature or other moving element and response is developed by electronic, magnetic and other components without mechanical motion. The solid-state components used are transistors, diodes, resistors, capacitors and so on. Static circuits accomplish the function of comparison and measurement. A relay using combination of both static and electro-magnetic units is also called a static relay provided that static units accomplish the response.

In static relays, the measurement is performed by electronic, magnetic, optical or other components without mechanical motion. Additional electro-mechanical relay units may be employed in output stage as auxiliary relays. A protective system is formed by static relays and electro-mechanical auxiliary relays.

BASIC STATIC RELAY

The essential components of static relays are shown in fig 20. Rectifier rectifies the relaying quantity i.e., the output from a CT or PT or a transducer. The rectified output is supplied to a measuring unit comprising of comparators, level detectors, filters, logic circuits. The output is actuated when the dynamic input (i.e., the relaying quantity) attains the threshold value. This output of the measuring unit is amplified by amplifier and fed to the output unit device, which is usually an electro-magnetic one. The output unit energizes the trip coil only when relay operates.

In a static relay the measurement is carried out by static circuits consisting of comparators, level detectors, filter etc while in a conventional electro-magnetic relay it is done by comparing operating torque (or force) with restraining torque (or force). The relaying quantity such as voltage/current is rectified and measured. When the quantity under measurement attains certain well-defined value, the output device is triggered and thereby the circuit breaker trip circuit is energized.

Is Windows 7 Backup and Restore Good Enough?

If you are looking for an efficient and effective way to backup and protect your Windows 7 PC then you may consider Windows 7 backup and restore. Windows 7 includes backup and restore for all versions of Windows 7 and is included in the operating system so there is no additional cost. Sounds perfect - doesn't it? Unfortunately it has a few huge flaws!

1. Does not support getting your data offsite. If you have a fire your data goes with your computer. How about the power surge? Isn't your external drive on the same power source? What if your external drive has a defect you aren't aware of (happens all the time)? You won't know it until you need to try to restore.

2. No continuous backup. The file you need is often the one you just lost. Continuous backup is a great way to backup data all the time so you lose a little as possible.

3. Windows 7 backup and restore doesn't backup open files. If you leave a file open during a backup most likely it gets skipped.

4. Scheduled backups require you to leave your computer on and pretty much leave it alone. You won't be able to use it to well if your hard drive is spinning during a backup. Scheduled backups are missed and cancelled all the time leaving you exposed.

Do you want to lose documents and pictures? NO! When you finish reading this article you will learn a better way to backup and restore Windows 7 and understand why using the free backup and restore software in Windows 7 can cost you big later.

How can you overcome the problems above and protect yourself?

1. You need to use an online backup service. Yes it costs a few dollars a month but it will get your data off site which is critical. Once it is out of you house or office many of the physical concerns are gone and if you need to restore you can from any high speed internet connection.

2. Many online backup services offer continuous backup service which means that as you create data they are backing it up. Since the data is small it creates little burden on the computer but gives you the most complete backup possible.

3. If you are using continuous backup you are backing up open files - no documents or pictures get skipped.

4. A continuous backup also requires no schedule. After completing the first backup (which can take some time) you are backing up every time you turn your computer on and connect to the internet.

Follow these guidelines and you will never lose data on your computer again!

How To Remove Programs In Windows 7

When you are using Windows there are times where you will need to remove a program from your system. When using Windows 7, if you have never used this or Vista before, you might find it difficult to remove an application since it's a newer process. Learn how to do this.

If you are used to using XP, then you know that you go to the Control Panel and find Add/Remove programs to get rid of the applications you don't want anymore. In Windows 7 you are looking for the Programs and Features tool. This is something you can use that will help you get rid of those applications that you don't want.

There are a few other options as well. You can use the uninstall tool that is in the folder of that application. Not all programs have this option, but some come with an uninstall tool.

At times, there is an option to remove a program in the start menu folder. There are sometimes icons there that you can press to remove the application from the system. Not every single one does this but many applications do.

How come a certain program won't allow me to remove it from my computer?

Sometimes when a program is active, you can't remove it from your system. You need to close the program first, before you can remove it from your computer. At times this is hard to do since you might not realize that the program is actually open, as it's not shown in your taskbar.

Sometimes there is a virus or spyware on your machine that you want to remove, but they are programmed so that you can't get rid of them that easily. You need to use a virus protection tool that can go into safe mode to remove the problem. In safe mode these programs won't be active, so they can be removed from your system by these tools.