Photovoltaic Power System and Wiring Module Interconnection

Photovoltaic (PV) is the field of technology and research related to the application of solar cells for energy by converting sunlight directly into electricity. The following Photovoltaic Power System manual is a suggested practices manual examines the requirements of the 2005 National Electrical Code (NEC) as they apply to photovoltaic (PV) power systems. In this manual you will get the design requirements for the balance-of-systems components in a PV system are addressed, including conductor selection and sizing, overcurrent protection device rating and location, and disconnect rating and location.

This manual is divided into sections which covers discussion on Photovoltaic Modules (including Modules Marking, Wiring, Module Interconnection, Tracking Modules, Terminals, Transition Wiring, Module Connection Access, Module Connectors, and Splices), Conductor Color Code, PV Array Ground-Fault Protection, PV Array Installation and Service, Grounding (including size of DC grounding electrode conductor, point of connection, charge controller, ungrounded system), Equipment Grounding, Inverter AC Outputs, Conductor Ampacity, Overcurrent Protection, Batteries, Generators, Charge Controller, Inverters, Stand Alone Distribution System, etc.

Copper conductors are recommended for almost all photovoltaic system wiring. Copper conductors have lower voltage drops and better resistance to corrosion than other types of comparably sized conductor materials. Aluminum or copper-clad aluminum wires can be used in certain applications, but the use of such cables is not recommended—particularly in dwellings. All wire sizes presented in this guide refer to copper conductors.

Find more information about Photovoltaic Power System and Wiring Module Interconnection in the following manual. (source: scribd.com)

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Digital control system applications

Digital Control System is a branch of the control system with continuous time processes in the region associated with the digital controller as the controller of the control elements that control systems and computing discrete time. Depending on requirements, a digital controller can be shaped microcontroller and ASIC to a standard desktop computer. Because the digital computer system is discrete, then the Laplace transform is used in the control system is replaced with the Z-transform. Therefore, you must understand about the concept of continuous time and discrete time concept.

Flow Chart - Digital Control system applications

Digital computer also has a limited precision (See quantization) extra care needed to ensure that errors in the coefficients, A / D conversion, D / A conversion, etc. do not produce unwanted effects or planned.

The application of digital control can easily be done when used in a feedback form. Since the creation of the first digital computer in the early 1940s the price of digital computers has dropped significantly. The reason this is one of the many reasons for the application of digital control systems for the control of the control system. Other reasons:

Flexibile: easy to configure and reconfigure through software

* Scalable: can be set up programs tailored to the limits of memory or storage space at no extra cost

* Adaptable: program parameters can be changed with the times

* Static operation: digital computers are much more susceptible to environmental conditions rather than of capacitors and inductors

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XM Satellite Radio Vs Sirius for your Auto Sound System Selection

If youre in the market for a new auto sound system you might want to seriously take a moment and consider whether or not you would be benefited by subscribing to either Sirius or XM Satellite Radio. Both of these subscription-based services have something wonderful to offer their subscribers and both of them require specialized equipment in order to operate. This means if you are going to wish to use either service, you will need to have decided which service before you have your auto sound system installed.

It really doesnt matter which of these you choose they each have different features that will appeal to a wide variety of audiences. You will find some wonderful competition among the two not only by way of music radio but also talk radio. If you really love talk radio you really need to subscribe to one of these in order to find a treasure chest of talk radio gems. You will find everything from the mundane to the controversial. From Oprah to Howard Stern exist in the realm of satellite radio, which seems to not only be catching on but also here to stay.

It has been commented on many times that XM Satellite Radio has a strong lead when it comes to subscriptions. This is very true but you should also keep in mind that the new subscribers seem to be leaning more towards Sirius for their satellite radio rather than going with the traditional favorite. Ive checked out the line up and cant see that one has much of a clearly defined lead over the other so I cant give a definitive reason for the massive new subscribers to Sirius or even the phenomenal lead that XM Satellite radio is currently enjoying. Regardless if this is something that might interest you, you really should check out each website and decide for yourself which, if either, is more appealing to you as well as whether that appeal is worth the investment and the monthly subscription fee.

I will say this however: XM Satellite Radio for the moment seems to have much better toys to offer consumers. That being said, Im actually quite surprised that the vast number of new subscribers are going with Sirius rather than XM. Of course, being the gadget geek that I am, I am basing that surprise solely on the fact that XM seems to have much better toys. At the moment XM is offering some really cool gadgets that double not only as XM Satellite Radio receivers but also offer GPS functionality and navigation assistance and controls. Some of these devices even go one step further and play DVDs, CDs, MP3s, among other things.

Believe me, Sirius has a lot to offer its customers as well, Im simply thrilled over select items that can be found at XM that I really havent seen adequate competition for elsewhere. On the level of music, both seem to carry similar genres, lineups, etc. The same holds true for the Talk radio line up. The only major difference I am finding between the two are the gadgets. Even the prices are rather competitive with one another. I see only one other major difference and that is the fact that Sirius offers a lifetime membership that cost about the same as the five-year plan from XM Satellite Radio. The thing to remember however is that the lifetime membership is for the lifetime of the device not the subscriber.

I should also point out that opting for satellite radio more than likely will not eliminate your need for a new auto sound system it may however pose certain requirements for the type of sound system you will be able to choose. One thing I have noticed with both companies is that there are plenty of devices from which to choose. You will have your hands full selecting the right equipment for your auto sound system upon which to enjoy the wonderful sounds that satellite radio will bring to your ears each and every day.

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5 Zone Alarm System

This is a complete alarm system with 5 independent zones suitable for a small office or home environment. It uses just 3 CMOS ICs and features a timed entry / exit zone, 4 immediate zones and a panic button. There are indicators for each zone a "system armed" indicator. The schematic is as follows:

Circuit Notes

Each zone uses a normally closed contact. These can be micro switches or standard alarm contacts (usually reed switches). Suitable switches can be bought from alarm shops and concealed in door frames, or window ledges.

Zone 1 is a timed zone which must be used as the entry and exit point of the building. Zones 2 - 5 are immediate zones, which will trigger the alarm with no delay. Some RF immunity is provided for long wiring runs by the input capacitors, C1-C5. C7 and R14 also form a transient suppressor. The key switch acts as the Set/Unset and Reset switch. For good security this should be the metal type with a key.

Operation
At switch on, C6 will charge via R11, this acts as the exit delay and is set to around 30 seconds. This can be altered by varying either C6 or R11. Once the timing period has elapsed, LED6 will light, meaning the system is armed. LED6 may be mounted externally (at the bell box for example) and provides visual indication that the system has set. Once set any contact that opens will trigger the alarm, including Zone 1. To prevent triggering the alarm on entry to the building, the concealed re-entry switch must be operated. This will discharge C6 and start the entry timer. The re-entry switch could be a concealed reed switch, located anywhere in a door frame, but invisible to the eye. The panic switch, when pressed, will trigger the alarm when set. Relay contacts RLA1 provide the latch, RLA2 operate the siren or buzzer.

Author : Andy Collinson

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