Saturday, 19 September 2015

UPS/INVERTER-Common Problems and Solutions

Inverter or UPS are the power backup devices which protect not only from the electricity blackouts and also from lot of other unseen activities happening in it such as Voltage spikes,sags,Noise,frequency variations and etc...,So friends if you thought your UPS is only a backup solution for you, better understand the risks that your UPS undergoes.


UPS,INVERTER Problems and Solutions such spike,sag,harmonics,noise


Saturday, 4 April 2015

Solar Bajaj or Solar Rickshaw or Solar Tuk Tuk



Model 1:

This is a 3 wheeled Solar Bajaj operates with the sun as the power source. This auto rickshaw was converted to an electric auto rickshaw by removing its petrol engine replaced with 2 Lynch motors which are connected in series on the back wheels.This auto rickshaw is having 4 x 85 Watt BP solar panels which is charging 4 x 16 Volt Li-Ion batteries.


solar bajaj,solar autorickshaw,solar rickshaw,sun bajaj,solar auto



Model 2:

This is a 4 wheeled solar vehicle which already had 8 x 80 Watt panels that were reduced to 6 panels for safety because 480 Watts was sufficient to power the 2 x 12 Volt batteries operating at 24 Volts. It reaches a speed of 40 kph and can able to carry 4 passengers for 100 kilometres in a day.


Solar cycle,solar bajaj,solar vehicle




Model 3:

This solar vehicle is sponsored by Euromoney Investor PLC, and the Moss Family was made by Cycles Maximus of Bristol for The BBC Tomorrow’s World Road Show and was cycled from the NEC Birmingham to Earls Court.

Solar cycle,solar bajaj,solar vehicle

Model 4:

This Solar Vehicle is based on the London cycle taxi with 2 x 85 Watt solar panels on the roof and power from a Lynch motor. It gives a good illustration of power from the panels and a human as it is generally accepted "that a person can" when cycling produce 85 Watts; so the roof panels are equivalent to 2 cyclists power, which does not stop working at traffic lights or during lunch, the power being stored in 2 x 12 Volt batteries.

Solar cycle,Solar bycycle,solar bajaj,solar vehicle

Model 5:

This Vehicle is sponsored by Harvest Energy was built in Udaipur,India. The hybrid drive is from pedals and a Lynch motor attached to the front wheel with the power being provided by 3 x 75 Watt solar panels producing 36 Volts from 3 x 12 Volt Lead Acid batteries. It has excellent performance up hills, can carry 3 passengers and is substantially built.





Model 5:

This is known as the ‘Boys Toy ‘ as it was built by James and Simon Moss from an Indian cycle rickshaw parts bought in Delhi and assembled in Udaipur with the addition of a Heinzmann hub motor on the front wheel, 2 x 75 watt solar panels and 2 x 12V small lead acid batteries. It is very robust having been in 2 crashes and overturned. Like the other solar vehicles it was presented to Arvind Singh Mewar of the MMCF at a grand ceremony in the Old City Palace and Simon Moss, then aged 13, made the often quoted statement “When I am old the Oil Age will have passed”




Model 6:

Solar no 5 is a star, sponsored by Petrex and built in the UK by the remarkable and brilliant engineer Cedric Lynch. It is so efficient it covered 150 kilometres, carrying 4 passengers, in 1 day just from the solar power. It has 6 x 85 Watt panels and is based on a light weight frame with 4 mountain bike wheels with low friction hubs. Power is from a 200 mm Lemco Lynch permanent magnet motor and incorporates a Brusa controller which has regenerative braking .





Model 7:

This is a converted Bajaj Kawasaki KB 100cc motorcycle. The engine is replaced with an Etec Lynch motor and Brusa controller and instead of petrol the power is stored in 2 x 85 Amp/hr Li Ion batteries. It is used daily by the garage staff for errands around town and is recharged from a portable solar bike shed that keeps the bike cool whilst charging.




Model 8:


This was sponsored by the Donald Family and was built in the UK by 2EV in Cornwall. It is based on the Piaggio small truck and with its large engine had impressive acceleration and a top speed of 85 kph. It is now used as the “Mother ship” charging from the 6 x 85 Watt solar panels the electric scooters and motorbikes Solar Nos 10 – 15.





Model 9:

This was designed by Neil McClaren a young cycle enthusiast who was sponsored by Collinda to work on new designs for solar rickshaws in Udaipur. The vehicle is extremely easy to drive and steer but even with 7 gears is hard to pedal due to the absence of a free wheel shortly to be fitted.



Model 10:

This Vehicle is made in the Palace garage at Udaipur incorporates many of the best features of the earlier models. Sole drive is a Lynch motor on the front wheel. It has 3 x 75 Watt solar panels and 3 x 65 Amp/hr lead acid batteries. It is a very convenient town vehicle and a similar vehicle is being built for the testing programme/taxi service at the University.




Monday, 23 March 2015

Types of Motor Starting Methods

Types of Motor starting Methods,motor speed control,frequency control,voltage control for motor,auto transformer speed control,winding control for motor


Motor starting methods 

MethodAdvantagesDisadvantages
Across - the - LineSimple, Cost-EffectiveHigh Current Inrush
High Starting Torque
Abrupt Start
Reduced-voltage autotransformerHigh output torque vs. starting current.
Some Flexibility in starting characteristics due adjustable taps on auto-transformers
Limited duty cycle
Large equipment size due to autotransformers
Reduced-Voltage Resistor or ReactorHigh output torque vs. starting currentLimited duty cycle
Limited flexibility in starting characteristics
Higher inrush current than with reduced-voltage autotransformer
Large equipment size due to resistors/reactors
Wye-DeltaRelatively low inrush current
Relatively simple starter construction
Good for long acceleration times
Relatively low output torque vs. starting current
Limited flexibility in starting characteristics
Requires special motor construction
Part-WindingRelatively Simple starter constructionRelatively low output torque vs. starting current
Not suitable for frequent starts
Requires special motor construction
Solid-state soft starterSmooth Acceleration
Low inrush current
High flexibility in starting characteristics
Typically offers deceleration control also
Typically integrates with industrial automation
infrastructure
Relatively Expensive
Sensitive to power quality
Heat dissipation and ambient temperature are a concern
Rotor ResistanceSmooth acceleration available
Good flexibility in starting characteristics
Can be used for speed control also
Complicated controller design
Requires expensive wound-rotor motor construction
Adjustable
Speed Drive
Smooth Acceleration
Low inrush current
High flexibility in starting characteristics
Offers deceleration and speed control also
Typically integrates with industrial automation
infrastructure
Cost-prohibitive unless speed control is required also
Sensitive to power quality
Heat dissipation and ambient temperature are a concern
Continuous harmonic currents can create power quality issues

Ref:  http://electrical-engineering-portal.com/comparison-of-motor-speed-control-methods?utm_source=Technical+Articles&utm_campaign=e9ea0b385f-RSS_EMAIL_CAMPAIGN_MAILCHIMP&utm_medium=email&utm_term=0_ae069f0d91-e9ea0b385f-320603685

Monday, 16 March 2015

Transparent solar cell-Turns Window & Screen a Power Source

Transparent solar cell-Turns Window & Screen a Power Source,window power,window solar,screen solar cell


Researchers at Michigan State University have created a fully transparent solar concentrator, which could turn any window or sheet of glass (like your smartphone’s screen) into a photovoltaic solar cell. Unlike other “transparent” solar cells that we’ve reported on in the past, this one really is transparent, as you can see in the photos throughout this story. According to Richard Lunt, who led the research, the team are confident that the transparent solar panels can be efficiently deployed in a wide range of settings, from “tall buildings with lots of windows or any kind of mobile device that demands high aesthetic quality like a phone or e-reader.”

Scientifically, a transparent solar panel is something of an oxymoron. Solar cells, specifically the photovoltaic kind, make energy by absorbing photons (sunlight) and converting them into electrons (electricity). If a material is transparent, however, by definition it means that all of the light passes through the medium to strike the back of your eye. This is why previous transparent solar cells have actually only been partially transparent — and, to add insult to injury, they usually they cast a colorful shadow too.

Transparent solar cell-Turns Window & Screen a Power Source,window power,window solar,screen solar cell
Transparent solar cell-Turns Window & Screen a Power Source,wavelength of transparent solar cell




The organic salts absorb UV and infrared, and emit infrared — processes that occur outside of the visible spectrum, so that it appears transparent.

To get around this limitation, the Michigan State researchers use a slightly different technique for gathering sunlight. Instead of trying to create a transparent photovoltaic cell (which is nigh impossible), they use a transparent luminescent solar concentrator (TLSC). The TLSC consists of organic salts that absorb specific non-visible wavelengths of ultraviolet and infrared light, which they then luminesce (glow) as another wavelength of infrared light (also non-visible). This emitted infrared light is guided to the edge of plastic, where thin strips of conventional photovoltaic solar cell convert it into electricity. [Research paper: DOI: 10.1002/adom.201400103- "Near-Infrared Harvesting Transparent Luminescent Solar Concentrators"]

If you look closely, you can see a couple of black strips along the edges of plastic block. Otherwise, though, the active organic material — and thus the bulk of the solar panel — is highly transparent. 

Michigan’s TLSC currently has an efficiency of around 1%, but they think 5% should be possible. Non-transparent luminescent concentrators (which bathe the room in colorful light) max out at around 7%. On their own these aren’t huge figures, but on a larger scale — every window in a house or office block — the numbers quickly add up. Likewise, while we’re probably not talking about a technology that can keep your smartphone or tablet running indefinitely, replacing your device’s display with a TLSC could net you a few more minutes or hours of usage on a single battery charge.

The researchers are confident that the technology can be scaled all the way from large industrial and commercial applications, down to consumer devices, while remaining “affordable.” So far, one of the larger barriers to large-scale adoption of solar power is the intrusive and ugly nature of solar panels — obviously, if we can produce large amounts of solar power from sheets of glass and plastic that look like normal sheets of glass and plastic, then that would be big.

Fundamentals of Resistance,Capacitance and Impedance


Resistance:
Resistance is essentially friction against the motion of electrons. It is present in all conductors to some extent (except superconductors!), most notably in resistors. When alternating current goes through a resistance, a voltage drop is produced that is in-phase with the current. Resistance is mathematically symbolized by the letter “R” and is measured in the unit of ohms (Ω).
Reactance:
Reactance is essentially inertia against the motion of electrons. It is present anywhere electric or magnetic fields are developed in proportion to applied voltage or current, respectively; but most notably in capacitors and inductors. When alternating current goes through a pure reactance, a voltage drop is produced that is 90o out of phase with the current. Reactance is mathematically symbolized by the letter “X” and is measured in the unit of ohms (Ω).
Impedance:
Impedance is a comprehensive expression of any and all forms of opposition to electron flow, including both resistance and reactance. It is present in all circuits, and in all components. When alternating current goes through an impedance, a voltage drop is produced that is somewhere between 0o and 90o out of phase with the current. Impedance is mathematically symbolized by the letter “Z” and is measured in the unit of ohms (Ω), in complex form.
Perfect resistors (Figure below) possess resistance, but not reactance. Perfect inductors and perfect capacitors (Figure below) possess reactance but no resistance. All components possess impedance, and because of this universal quality, it makes sense to translate all component values (resistance, inductance, capacitance) into common terms of impedance as the first step in analyzing an AC circuit.
Resistor,capacitor,inductor example explanation,resistance vs reactance,Fundamentals of resistance,capacitance and reactance
Perfect resistor, inductor, and capacitor.
The impedance phase angle for any component is the phase shift between voltage across that component and current through that component. For a perfect resistor, the voltage drop and current are always in phase with each other, and so the impedance angle of a resistor is said to be 0o. For an perfect inductor, voltage drop always leads current by 90o, and so an inductor's impedance phase angle is said to be +90o. For a perfect capacitor, voltage drop always lags current by 90o, and so a capacitor's impedance phase angle is said to be -90o.
Impedances in AC behave analogously to resistances in DC circuits: they add in series, and they diminish in parallel. A revised version of Ohm's Law, based on impedance rather than resistance, looks like this:
ohms law


Kirchhoff's Laws and all network analysis methods and theorems are true for AC circuits as well, so long as quantities are represented in complex rather than scalar form. While this qualified equivalence may be arithmetically challenging, it is conceptually simple and elegant. The only real difference between DC and AC circuit calculations is in regard to power. Because reactance doesn't dissipate power as resistance does, the concept of power in AC circuits is radically different from that of DC circuits.
Know This:
  • Impedances of any kind add in series: ZTotal = Z1 + Z2 + . . . Zn
  • Although impedances add in series, the total impedance for a circuit containing both inductance and capacitance may be less than one or more of the individual impedances, because series inductive and capacitive impedances tend to cancel each other out. This may lead to voltage drops across components exceeding the supply voltage!
  • All rules and laws of DC circuits apply to AC circuits, so long as values are expressed in complex form rather than scalar. The only exception to this principle is the calculation of power, which is very different for AC.


Friday, 27 February 2015

Inverter/Offline UPS and Online UPS

Any person will tell you that both the inverter and the UPS are used to give your electrical and electronic appliances and gadgets a backup power support when there is an electricity failure in your office or home.

 A layman will also tells you that the electricity backup from the UPS is instant and it does not let your electronic gadgets to get switched off and the electric supply is continuous and that is why it is given a name UPS which stands for uninterrupted power supply. 

However, the backup supply of power from an inverter gets delayed by one or two seconds, which causes your electronic gadgets to get switched off and you have to switch them on to start them again. This is the reason that most people use UPS to support backup of electricity to their computers and other costly electronic equipment, which otherwise get damaged due to sudden power failure. 

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Fig.1&2 shows the block diagram of a INVERTER vs UPS.

Let us now define the difference between an inverter and a UPS from the technical point of view:

UPS: The one power cable of your UPS is fixed in the power socket of your wall when the power is on. So, the UPS keeps on getting a regular power supply from the mains when the power is on. This AC power received from the mains power source continuously keeps on being converted to DC. This DC power keeps on charging the battery of the UPS in a continuous charging mode. 

So, the battery of the UPS is always kept charged during the time when the power is there in the mains. The output from the battery goes to the Sine wave inverter of the UPS. It converts DC to AC and this feeds the equipment. This makes it very clear that the power to your electrical gadget which is connected to the UPS is always supplied from the battery. 

Due to the power always being drawn from the battery to the electrical equipment, there is no time lag in case of electricity failure and the flow of the mains power stops. It is only the battery of the UPS which stops from being charged since there is no power in the mains. However, the backup power from the battery of the UPS keeps on being supplied uninterrupted till the battery is discharged and is no more able to supply the power to the eqauipment. 

This is why we find that the backup power of the battery of the UPS is of very short period ranging from 15 – 20 minutes upward. The more is this backup time of the UPS battery, the more will be the cost of the UPS. Otherwise also, the circuitry of the UPS is expensive making the UPS even of a small backup time more costly. 

Inverter: As far as the power to the inverter is concerned, like UPS it also comes from the mains for the inverter battery to get charged when there is no power cut off. The main difference between the inverter and the UPS lies in the fact, that in an inverter, the power is directly sent to the output which is connected by wiring to various appliances. 

At the same time the AC is also converted to DC and this DC is constantly charging the battery. On the other hand, the power to the appliances is not directly sent to the output but it goes from the battery of the UPS which keeps on getting discharged. A sensor and relay mechanism checks whether the mains is ON or OFF in an inverter. When the mains get switched off, the relay mechanism triggers to switch from mains to inverter. Rest is same like the UPS. Because of this sensor and relay, there is a gap between triggering.