Sunday 31 May 2015

complete electrical formulas sheet
















resistor color code



The colors brown, red, green, blue, and violet are used as tolerance codes on 5-band resistors only. All 5-band resistors use a colored tolerance band. The blank (20%) "band" is only used with the "4-band" code (3 colored bands + a blank "band").








Why Motor rated in kW instead of kVA




Why Motor rated in kW/Horsepower instead of kVA?



We know that Transformer rating may be expressed in kVA as well as Generator and Alternator rated in kVA Designer doesn’t know the actual consumer power factor while manufacturing transformers and generators i.e. the P.F (Power factor) of Transformer and Generator/Alternator depends on the nature of connected load such as resistive load, capacitive load, and inductive load as Motors, etc. But Motorhas fixed Power factor, i.e. motor has defined power factor and the rating has been mentioned in KW on Motor nameplate data table. That’s why we are rated Motor in kW or HP (kilowatts/ Horsepower) instead of kVA.

In addition, Motor is a device which converts Electrical power into Mechanical power. In this case, the load is not electrical, but mechanical (Motor’s Output) and we take into the account only active power which has to be converted into mechanical load. Moreover, the motor power factor does not depend on the load and it works on any P.F because of its design.

Wind solar hybrid street lighting



Wind solar hybrid street lighting is an intelligent and complete stand-alone LED street lighting system. Composed of solar modules and small wind turbine, deep cycle batteries, controller and one or few street lights, this hybrid system harvests energy from both wind and solar and store it in deep cycle batteries to power street lights during night. Using a combination of wind & solar resources the system will provides a stable and constant flow of power to power the street lighting.



The major advantage of wind solar hybrid street lighting system is that when solar and wind power productions are used together, the reliability of the system is enhanced. Additionally, the size of battery storage can be reduced slightly as there is less reliance on one method of power production. Often, when there is no sun, there is plenty of wind. Wind speeds are often low in periods (noon time & summer) when the sun resources are at their best. On the other hand, the wind is often stronger in periods (evening time & spring, winter) when there are less sun resources. Even during the same day, in many regions worldwide or in some periods of the year, there are different and opposite patterns in terms of wind and solar resources. And those different patterns can make the wind solar hybrid systems the best option for street lighting.

Advantages Compare with Solar Street Lighting
Wider applicable areas – hybrid system offers a much better reliability and sustainability to areas with less solar radiation level, long rainy season or long winter.
Longer battery life – normally wind turbine generates more power during night, part of power generated will supply the light directly, part of power could charge the battery during night, so less charging and discharging loss from battery and also each battery charging cycle is prolonged.
More cost-effective in windy areas – in the area with annual wind speed of 5-7m/s, wind solar hybrid system could have higher production to power higher capacity LED lights or more lights which could lower the system overall cost. 
Easier installation & Maintenance – solar street light system cannot put bigger (max. 360W in two sections) PV panels on light pole considering wind load; wind solar hybrid system allows bigger capacity installed on light pole, which could generate enough electricity to power 2-4 LED lights, which means one power system supply for 2-4 lights, it will be easy for installation and maintenance.  

HYE Solar Street Light Systems Include:
● Photovoltaic (PV) module- monocrystalline/polycrystalline
● HY Series small wind turbine-400W/600W/1500W/3000W (12V/24/48/96V)
● Light source – ultra bright LED light 20/30/40/60/80/90/120W
● Controller – 5/10/15A wind solar hybrid controller, automatic light controller, automatic operation, multi work mode, over charge protection, high wind protection etc.
● Energy Storage – sealed maintenance free AGM gel deep cycled battery
● Battery Box – water proof design battery box
● Light Pole – 6/8/10/12/16m light pole with 30/50m/s wind resistance

Friday 29 May 2015

The 8 Best Ways To Make Your Home Audio System Wireless

Streaming music services like Spotify and Rdio are great, but as apps constrained to tiny phone or computer speakers aren’t always a great solution.

Up until recently there were few options to get internet radio, or other audio content, directly to your speakers without running wires. But as wireless technology becomes increasingly more reliable, companies have gotten the wireless bug and it’s now a lot easier to enjoy streaming music in your home, on good sounding speakers.

Here are some newest and best options for bringing wireless music to your old equipment, or building a new, expanded, sound system that reaches every room without tearing up walls and running wires in the process.

1. Beep – $49+



Beep is an attempt to give new life to old speakers. The hardware is a big volume knob which connects to most existing speakers via 3.5mm, RCA, or optical connectors. Beep joins to your home’s WiFi and allows playback from Pandora as well as your own music library. More music sources should also be confirmed soon.

The beauty of the physical volume knob is that it allows anyone to reach over and change the volume without pulling out your phone. You can also press on the center of the device to pause/play the music as well as double tap to skip songs.

Connecting multiple Beep devices enables multiple zone to either play back the same or separate content. The goal of Beep is to be open and accessible to as many speakers and configurations, as a way to get the most people streaming music wirelessly. Beep is currently available for pre-order at a discounted price of $49, with availability later this year at a listed price of $149.

2. Aether Cone Speaker – $399



Cone is a stand alone speaker that not only connects to streaming music online, it also incorporates podcasts and a user’s local library. The main feature isn’t what it plays, but how it plays, trying to anticipate what to play before being asked.

To do this, the speaker learns what you play, where you play it, and at what volumes. If you like smooth Jazz in the late afternoon when you get home from work, the speaker learns and starts doing it on its own. Because there’s a built in battery and can be moved around, the speaker also knows what content to play in the kitchen versus the living room.
If you do end up needing to tell the speaker what to play, you can press the center button and literally tell it what you’d like to hear. The outside ring of the speaker is the volume knob when spun one way and a skip mechanism when spun the other way.
Cone is available for pre-order and should ship in the summer.

3. Sonos – $199+



Sonos has long been the leader in wireless speakers, for a good reason too. The high end speakers should please most critical listeners with their sound and the content sources available are the most extensive among other options. That means that whether you subscribe to, or use, Rdio, Spotify, Beats Music, Rhapsody, Pandora, iHeartRadio, or another option, Sonos should have you covered.

The company now makes a host of different speaker options ranging from a small bedside Play:1 to the Playbar sound bar. All the speakers can be connected to each other or play independently which makes for an easy way to get different music to every room of the house.

The whole package makes Sonos one of the easiest wireless solutions to implement and control. Setup is notoriously simple, while control from Android and iOS is fairly full featured. Even though it can be seen as an expensive option, it’s right in line with the competition.

4. Samsung – ~$349/Bose $399+



The newest and most direct competitors to Sonos are Bose and Samsung. Both companies aren’t shy about targeting the incumbent either with very similar feature sets.

Samsung’s offering, the Shape speakers, use a mesh network just like Sonos, but also incorporates bluetooth into the mix as a way to expand compatibility with the most devices. As for Bose and its SoundTouch models, the direct WiFi system has dedicated buttons for streaming content so just like presets in your car, you can change what’s streaming with one touch.

Both Samsung and Bose will help push the wireless space forward, but at this point they’re still pretty limited in streaming sources and expandability compared to Sonos’ lineup.

5. Apple TV – $99



The one line pitch for Apple TV may be “Plays Netflix…other TV channels,” but this $99 box is all about AirPlay. How do you send content, specifically music in this case, to your home audio system? Connecting the Apple TV to your receiver or TV with sound bar allows you to stream music from any iPhone app to your much better sound system.

The box can independently play iTunes Radio and your entire music library through iTunes Match as well, but the highlight is being able to free most streaming sources from your phone’s tiny speaker.

6. Chromecast – $35



Much like Apple TV, Chromecast is Google’s hardware dongle which allows Android and iOS devices (as well as the Chrome browser) to send, or cast, content to play out of speakers connected to you TV.

Supported music apps include Google Music, Pandora, and Songza though more are being added all the time. There’s also the music video content of Vevo and Youtube as well. If you’re looking to get streaming music from your browser or mobile device to you sound bar or surround sound system, it’s hard to beat the $35 Chromecast.

7. Rocki – $49+



Similar to Beep, Rocki is a small device that connects existing speakers to your your WiFi network. The hardware supports speakers with a 3.5mm (headphone) or RCA connector. The device can also pair with other Rocki devices to add additional speakers to the mix.
The other interesting feature is the social aspect. That means that for your friends to play their music, they just need to download the Rocki app. There’s also an 8 hour battery so Rocki can be used in places without access to an electrical outlet.

Rocki was successfully funded on Kickstarter, but has opened pre-orders to anyone which ship at the end of March.

8. AirPort Express – $99



The AirPort Express is a router on its own, or a WiFi extender paired with an AirPort Extreme, but also a stealthy streaming audio component.

The AirPort Express is AirPlay enabled, so any speakers that get connected to the 3.5mm jack also become AirPlay speakers. Music can then be played from an iPhone or iPad directly, as well as from iTunes on Windows or Mac. If you have multiple AirPort Express devices, they can be combined or each play music separately as well. Years ago, the audio out on the tiny router was a huge differentiating feature, however, it’s become less so because of other cheaper options coming to market.

BASIC ELECTRICAL SYMBOLS