AmirShahzad.PK

The keyword you are looking for is "metamaterials".

 

For example: http://www.iop.org/resources/topic/archive/metamaterials/

Thanks. I will check it out.

I dont think invisible Making Clothes has been invented. It would be hard finding it on Google if it has.

May be. Yes, hard to find if you do not know the proper name.

No,gravity does not wear off or diminish by use. It doesn't get used up.

OK but if suppose an ideal situation then what will happen to the body experiencing no gravitational force?

This is the problem. As far as we know everything gets effected by gravity.

Yes but if suppose an ideal situation then what will happen to the body experiencing no gravitational force?

Recently I have been told that Science has been able to produce effect in the body that will allow light to pass through and do not return back may be through some clothes or any thing else. Is this really true. I am not able to came with some recent results by Googling.

I do not know much of Astronomy but this felt a interesting question to me posed by my cousin. My cousin wanted me to think on it but I enjoy and prefer discussions more than just doing it alone. As far as I know, when we walk or run on earth, we apply force against gravity. I read Newton`s third law of action and reaction in my School and college and that also applies here but I want to keep it simple. Also, jet rising up from the earth also work against gravity. All of these requires force against gravity but is this possible to reduce or even finish this gravity. I am not talking about doing this to the whole earth but some thing like a person wearing a specific clothes or something else do not get affected by gravity? Share your ideas about it. What would happen to such person who is not affected by gravity at all. Will he be able to stand on earth or will be attracted by other bodies in our galaxy? Or he will be able to jump high like people did in the moon.

I choose "Custom Wordpress Theme" as study project. I started working on "SRS" as it is due Tue 4 Aug, 2015. Just wanted to discuss because it will further enhance my work but not sure how would I do so? Publicly pasting my work will open the risk of being copied. Right now, I am finished with doing "Scope of Project" and "Functional and non Functional Requirements". Next will be "Use Case Diagram(s)" and will be dependent on preceding steps. Just wanted someone to review my work and I move forward. Unfortunately, there could be no one except internet whom I can show my work.

I am sorry, but I can't give you any guarantees about your inverter's output, as i don't have any experience with it, however at my work we have lots of computers running on UPS power supplies to protect them from surges and brownouts from our mains.

 

The charger in the UPS could still be connected to the battery even if the UPS is disconnected from the mains, if it is powerless it should not interfere with another charger, but I need to stress that I can't give any guarantee that connecting a second charger won't harm the UPS or the charger.

 

 

EDIT: If you are going to try this you need to know that a 12 volts 20 amperes charger will only give 12 x 20 = 240 Watts. If you need 300 Watts output then you need a 25 ampere charger and for 600 watts you need a 50 amperes charger. The battery can cover for a larger need for a short duration but if you want to run constantly then the charger need to be greater than your average consumption. Also the inverter have losses so you need to make sure you have a little extra for this too.

Al right.

Thanks. I will discussing this on Pakistani Forum and hope will be able to be clear about it.

Mean 50+ A charger would be suitable?

If it is a good inverter then it will not destroy your appliances, and if you already have used it for longer durations without mishaps then I don't think it will be more harmful for your equipment if you were to always use it.

 

The problem with another separate charger is when your mains voltage goes above 170 VAC and the UPS also tries to charge the battery, then there will be two chargers competing on the battery voltage and if they don't work together one or both could be destroyed.

 

If the UPS allows a separate charger and you can find a charger that is compatible with it, then it would probably work.

Not sure whether it is a good inverter or not but it is modified sine wave. I am using it from October 2014 and since then one of my PC supply has been spoiled. It was an exceptional case and happened after my stabilizer stopped working correctly.

I am sorry I have not mentioned in the above diagram but UPS will not be getting any power from the mains so only one charger will be charging the battery.

I don't think that my UPS does.

You have already wasted money, time and effort on the wrong equipment because you have tried to tell electrical experts what you should have.

 

Instead of saying "I want to stabilise my mains to 220 volts"

 

or even

 

My mains varies and sometimes drops as low as 180 volts.

 

Say I need to supply the following equipment { Insert List} and if possible why you think 220 volts is so critcal.

 

Then let the experts ask the questions designed to point you at the appropriate solution.

 

Also if I understand you correctly you are saying that you run power devices in the 10 amp range at 220 volts without any safety precaution (ie no earth)

 

I would advise you this is very dangerous and against Pakistan Electrical codes since at least as far back as 1937.

 

https://www.google.co.uk/#q=Pakistan+electrical+earthing+code

True

This is true I want to stabilize my voltage to 220

Yes my main voltage varies and 180 is not the lowest limit. Today, it has dropped as low as < 90 VAC

I need to supply equipment within 1000 VA range. Equipment are:

1 - Energy Savers

2 - Fans

3 - PC along with Lcd

4 - Laptop

5- mobile chargers

6 - Mortein lamps

7 - 350 watts juicer sometime mostly in day.

Off course, I do not use all these things at once as my inverter is only 600 watts but my load is not more than 300 watts usually. Juicer is mostly run for 5 - 10 minutes and at that time I try to minimize other load to ensure that load do not cross 600 watts limit.

When power goes off then my inverter starts to give backup and it give volts > 220. At that voltage all my fans run with fast speed but when light came back then inverter continue supplying main voltage as is and fans run too slowly and I feel annoyed by this difference so I believe 220 is critical so that I do not feel any difference in main as well as inverter mode.

I am not sure whether my devices are in 10 amp range or not because I do not understand amps system, only understand watts system my home wiring only has two cables no earth.

I am not sure whether this is against Pakistan electrical codes as my home wiring is so old and also I have seen new wiring around me which are also two wired only i.e. no earth. Pakistan was founded in 1947 so this 1937 codes might not be applicable.

If you want 220 VAC independent of input voltage then you need some kind of inverter.

 

It have to automatically switch from bypass mode when voltage drops to low and start to supply 220 VAC but still be able to continue charging its battery or capacitors in the intermediate circuit with the low input voltage.

(Or if you have very long periods with low voltage then you could have a separate charger and inverter and manually turn them on when they are needed.)

 

Much like your UPS but with an intermediate mode where it supplies enhanced power while still charging the battery from the low input voltage.

 

I have no idea of what models and brands there are on the market that can fulfill your needs, but I am sure a local salesman or the second repairman can help you.

(If your voltage normally is so low, then there should be lots of different equipment to choose from.)

I already have inverter. It has two charging modes narrow and wide. In narrow charging mode, It charges battery and supply voltage as coming from mains if the voltage is >= 170 VAC but below that it provide 220+ VAC from the battery but do not charge the battery. This is the drawback.

I am also thinking of charging my UPS battery separately using a separate charger and try to provide 12 V to UPS through this charger and supply no input to UPS. In this way ups will always work in backup mode always and supply 220+ but wonder this modified sine wave from the ups always would be dangerous for my appliances? Does stabilizer output pure sine wave? Just have a look and tell whether is this possible?

There is nothing in that device that will make it able to output exactly 220 VAC. It has three stages, adding a low voltage to input, removing a low voltage from input or forwarding input to output.

(Also if the input voltage goes way too low the relays will not be able to activate and it can only forward input to output.)

 

 

It is likely that you have changed the settings for the two potentiometers such that the two relays no longer can activate as they should.

 

Finding the correct settings for the potentiometers without access to adjustable voltage is not going to be easy and since it requires adjusting with live voltage it will be dangerous.

 

My recommendation is that you take it back to the second repairman and let him redo the adjustment and check the unit again.

 

 

But even with the settings back as they were intended, the unit will not be able to give 220 VAC from 90 VAC.

 

However when your main voltage is above 180 VAC it can stabilize the voltage and ease the strain on your UPS.

Ok. Thanks. This was what the second repair person told me and he used Variac Transformer to set this screw like things (potentiometers?). When I told him about my voltage condition then he told me that this unit will work only at 180 Vac. So he called it useless for me. Can you suggest some stabilizer or regular which give constant 220?

The front implies that the device can handle 90 to 250 VAC but it does not specifically guarantee that it will output 220 VAC from 90 VAC. From the image it looks more like there is one indicator light that shows that the input is between this level and one indicator that shows when the output is around 220 VAC.

 

Did you take note on how they where located so that you can return them to the position the second repairman placed them in?

 

How do you know it gives power if the electric iron didn't work?

 

Good.

 

What voltage did they show with the electric iron connected?

 

Can you get a light bulb for testing? It is not as good as a voltmeter, but satisfies to give a rough voltage indication and is not expensive.

 

You also missed out to reply to this important question:

Oh, I see but I was believing it will output exact 220 V irrespective of input voltage fluctuations within the specified range. No indicator light blows only when unit is working and indicator meters show voltage at input level and voltage at output level.

No.

When connected my UPS from it, it worked as its LCD was showing volts but not 220 but when connected electric iron, it didn't work even indicator light didn't blew. At the same time when I tried on normal socket, electric iron worked.

To be honest, I didn't notice the voltage when connected electric iron but input and output meter was showing voltage.

Ok I will.

Sorry about that and reply to important question is "Usually I noticed below 180 VAC as summer here and voltage is mostly low and it was giving same voltage on output e.g if 179 VAC on input then same on output as I am able to guess from analog meters".

This is what I understand about Li-Ion batteries and I do with mine. I get 6-7 hours and got it last December.

 

A battery has a maximum number of charges; about 300-400. I leave mine on mains adapter all the time*, and run it on battery, down to the low-battery warning only about once a month. Never discharge a battery until it's absolutely flat. Charging to 100% and then running it flat will kill it in months. The ideal % range to to be charging and discharging is 80% down to 20% before recharging again... if you have to.

 

Get some kind of low tilted stand that you can put the laptop on to put more air-space under it so it doesn't get too hot...heat hurts batteries.

 

This link will take to The Battery University website, which is great for learning about them. Have a look around it.

What do you mean by a flat battery? But how do I know that battery is charged up to 80% now and discharged to 20% now? It is hard to keep such care. My windows system do not give any notification when battery is fully charged but I can know from laptop led indicator but it gives notification when battery is discharged to 10%.

Yes, I also believe the same. The reason of my battery being killed is of heat because it`s summer here. Now I started using cooler pad with my laptop by connecting USB cable in to it. Although it make laptop heavy and uncomfortable to taken in lap but I am doing it for summer and might not do same in winter. I already have sent my 9 cell battery in warranty and currently running old 6 cell came with laptop. You might be surprised but I purchased this laptop (used) in October 2014 and it came with 6 cell battery. Battery was providing me with 2 hours backup until I was fully charging followed by fully discharging but when I started keeping it plugged all the time then battery started losing capacity and now it doesn't even give a backup of 20 minutes even. Even laptop bios give a notification of replacing battery.

Yes I have visited this website before purchasing laptop and not able to reach on some conclusion. Still confused, how should we use batteries? I talked to hp support personell and they too recommended me fully charging followed by discharging but they recommended me not to use modified sine wave Uninterrupted power supply unit but unfortunately I have this type of unit at my home.

 

*Leaving the adapter in all the time will not kill the battery because it will switch charging off once it is full.

This is what a new and old laptop seller and repair person of my city told me but still not sure what is reality.

 

Note: If you use a hard-drive data cleaner, like Ccleaner, it will wipe out all the logs, causing repeat messages about calibrating etc.

No I didn't use it on this version of windows. Also, battery low time along with calibrating messages guarantees fault.

 

From a Google search your probably using 230 volt 50 hertz single phase correct?

I called local office in my city and they told me it`s single phase but they were not able to confirm about frequency. My electricity company website is http://www.pesco.gov.pk/. This might help you.

 

If not can you post a picture of each plug and socket. (This will help identify your electrical supply).

Yes. Here are they BTW, sorry for using Dropbox again but I am not able to post these too photos on this forum.

 

also I couldn't track down any technical manuals on your components.

Somewhere on each device there should be a nameplate with details.

Make and model number

Wattage

Input/ output power

FLA (full load amps)

Supply and output amps.

 

The other question is "are these devices single or three phase?". At 230 watt it can be either. The trouble shooting and circuitry will vary on the last answer.

Off course single phase as local electricity office told me.

 

As far as changing the relays from 10 amps to 30 amps this won't deliver more power. The circuit supplying the relays are designed to deliver 10 amp max. All this will do is reduce the chance of relay damage from overcurrent.

I see.

 

Replacing the relays though may be necessary just don't expect extra power. Ideally you should replace one component with an identical or compatible component. Not redesign the circuit at your level of skill.

Agree

 

Do you have a digital multimeter?

Do you know how to test for an open or short using resistance?

No

No

 

............................................

Thanks for the tests but I require digital multi meter as well as other things to do this. I just inquired by calling and they only offered me analog multi meter for about 3$ and I can replace whole circuit of my unit including identical relays for 4$ including 1$ service. If I go for 30 A relays then it will charge me 5$ including service charges. Now I believe it would be better if I take this unit again to repair person and try by replacing circuit. As I believe, there are only two main parts in this unit, transformer and this circuit and I wish transformer would be alright. If it develops some fault then I might have to bear costs equal to buying new unit.

Just a suggestion

Which stabilizer should I buy if I want a constant 220 V irrespective of fluctuations in mains voltage? Voltage may drop to as low as 100 V or even low and not sure about high voltage limit.

 

I have only looked at a few of the photos since I have serious trouble with dropbox from work

Sorry about that but I am having problem to upload so much photos to this forum so that`s why went with Dropbox.

 

and this seems to be a very simple device only able to stabilize voltage above around 180-190 VAC and up to 250-260 VAC with a maximum current of 10 amperes.

But this is opposed to what it says on it`s front plate

 

Of course the output voltage of the transformer would also decrease or increase with the same amount as the input voltage changes, which means that around 180 VAC the output would only be around 200 VAC.

That`s sad. This unit must output 220 V irrespective of fluctuations from 90 V - 250 V. If it cannot do this then it`s useless for me.

 

The second repairman seemed to know what he was talking about and doing, and since the unit apparently worked when he tested it, within the voltage limits he concluded the stabilizer only can handle, have you changed anything or did anything happen afterwards?

Yes I tried to rotated screw like things shown below clockwise and anti clockwise.

 

When the stabilizer is deemed to not be working, is it not working above 180 VAC input or not working below 180 VAC input?

It now only gives output equal to input. It gives power but 1000 W electric iron didn't work on it as I tested.

 

The stabilizer seem to have two meters on the front, what do they measure, input, output, voltage or amperes?

Input and output voltage respectively

 

What does the two meters on the stabilizer show with and without the 1000 watts electric iron connected?

Both were showing same voltage

 

What does the two meters on the stabilizer show with and without a standard light bulb connected?

Is the light bulb dark, glowing or shining?

Didn't try and I only have energy savers at my home.

 

OK, as I understand it

Good

 

Because of your location you have an unreliable mains electricity supply.

Yes

 

Is this correct?

I have 2 terminal electricity at my home Line and Neutral

 

What indications are there for earthing of units A and B (and load C)?

Sorry not sure what do you mean?

 

How many separate wires are there in the cable that connects ~

W to A

A to B

B to C

W socket is something like this but it have two sockets, one 2 terminal socket and one 3 terminal socket. I believe ground in this would be unconnected as my electricity is is only two terminal.

The unit I am trying to repair would be A and it has two wires

The inverter or ups whom I want to supply reliable voltage from Unit A is unit B has 3 wires and unit A has 3 terminal socket in it from which B connects.

The load or C unit have 1 wire (Line) but it connects from ups 3 terminal socket using 3 terminal plug and neutral and earth are unconnected in this plug. Load C is actually ups or inverter wiring for running home energy savers, fans and sockets. You can learn more about it here

 

Does this sem to describe it?

My unit A may be a line conditioner. As I could understand, line conditioner do a lot more than just maintaining constant voltage but not sure whether my unit A do all of the functions described. Anyhow, my unit A is a local Pakistani Stablizer. Although, I am not able to track my product online but here is similar local products

 

This is the most useful thing you have said so far and is a simple short answer to a question we asked at the beginning.

That`s great. After all, I said something useful

 

As a non electrical expert (no disrespect intended) why do you keep guessing what an electrical expert might need/want to know, instead of putting a lot of effort into telling us things of uncertain nature.

I am sorry about that. This might be my habit but I always clarify that this is my belief and may not be true. I will try to take care of it in future. Thanks for pointing out.

 

I will post a diagram later of what I think you have told us so that we can proceed.

Thanks.

 

First off never change the fuse ratings. If they are 10 amp fuses then this inverter is only designed to deliver roughly 8 amps normal load. The extra amps being for nuisance tripping

I am not talking about changing fuse as shown here 1 2 3 but talking about changing relays. Currently there are two relays. Each one is H200Fd12-10A also shown in here. I talked to one of the best electrical equipment whole sale dealer in my city and he said these can be replaced by maximum up to 30A (As these are the maximum relays he have. And also this is not inverter, a stabilizer.

 

PWM. Is pulse width modulation. It's a common type of circuit used in inverters. It takes a dc or ac voltage and converts it to digital sine waves. Which is not the same as AC sine wave. Not precisely though close enough for most equipment.

Got it. Thanks.

 

This type of circuit is rather complex as it involves capacitors and resistance values in RC timing circuits in older methods. Newer methods use specific pulse generation chips. Though this amounts to transistor diode circuits built into the IC chips. To deliver a modulating (rate and amplitude square wave). The circuits also includes diodes.

Understood that this circuit has capacitors, resistors and diodes but not understand RC timing circuits and pulse generation chips. See I have labeled my circuit

 

Ideally you want an oscilloscope to troubleshoot this circuit. Using a digital multimeter may not be enough.

Here is a few circuits for PWM. This circuit can be inside a single IC with component control circuits feeding the IC chip itself. Such as those variable resistors your adjusting. Those variable resistors are probably adjusting the TIMING CIRCUITS of the PWM digital on off rates.

http://www.ewh.ieee....8/08/PWMINV.HTM

I believe though not sure that 2nd repair person used Oscilloscope on my stabilizer. He checked by varying input voltages and later concluded that this stabilizer will only stablize voltage >= 180 Vac

Ok so those screw like things are actually are used to adjust resistors. I visited your given link and recalled my subject of PHY301 : Circuit Theory To be honest, I did not take this subject seriously.

 

now here is the concern. You had two occurances of sparking at a relay. If this is a solid state relay damage to the relay may have occurred. However if it is an electromechanical relay it may be fine. However other components on the same circuit as the relay may have been damaged. Ie an internal circuit of an IC or transistor. Troubleshooting these can give experienced and certified electronic techs with the right equipment nightmares.

How can I know whether it is solid state or electromagnetical relay? Understood one thing here the one I labeled as diode in this might be transistor? if yes then where is diode in this circuit? It is tough that`s why 2 repair person have not been able to repair it

 

Instead of powering up another inverter hook the output from this Inverter to other 220 ac devices. Light etc. You may damage your imini inverter as it expects a certain type of incoming voltage.

I connected 1000 watts electric iron and it`s indicator light didn't light up instead of my trying 2-3 times but when I tried same iron on normal power, it worked. Imini inverter expects voltage between 170 Vac - 280 Vac in narrow mode and 90 Vac - 280 Vac in wide mode.

 

Can you provide what the voltage specifications are on the imini inverter? Does it expect incoming DC power? ( most likely) ....

Already provided above and no it aspects AC. I rather should say it is a uninterruptible power supply but not sure why they have written inverter on it`s packing? You might be understanding it as a inverter which convert Batteries power to Ac and batteries require separate charger to be charged but this is full unit. It has built in 10A or 20 A (adjustable) charger, I have connected 100 Amp lead acid battery to it. When there is electric power it charges the battery and also provide ac to the home as in mains (no stabilizing) but when the electric power is cut off it provide 220+ voltage converting DC from the battery connected. I want to provide AC power to this inverter from a stabilizer because it do no stabilize in main mode, only stabilize in backup mode.

 

Think about that for a second.

inverters convert DC to AC...

your power regulator outputs rectified AC....

in other words its supplying the wrong type of voltage.....

(Which will damage both components)

(Inverters take power from battery power, DC direct current NOT AC, or rectified AC alternating current)

I think I have answered it.

 

I understand that English is not your first language, but I am seriously struggling to understand what you are trying to achieve.

Sorry about that but I hope I will be able to make it clear. Also, replied to Mordred so you can see answers to you concerns.

 

I really need a connection diagram to understand how you are connecting these two boxes and what you are expecting to happen.

I have tried and to be honest, I am not expert with it and this may not be something you are expecting.

 

If your only tools are mechanical hand tools how do you know what voltage the stabiliser is giving?

I have connected input of Imini inverter (UPS) to this stablizer and that Imini inverter (UPS) has lcd which shows input volts, output volts along with battery power, load and inverter mode. Main mode and backup mode. So I determined voltage from that lcd and also from analog meters in stabilizer.

As Studiot mentioned this is extremely dangerous. Only a certified professional should be repairing this unit.

How much experience do you have? What troubleshooting equipment do you have available ? As Studiot asked have you tried it under load?.

 

Further questions will depend on the answer to question 1 and 2.

 

I never feel comfortable telling someone how to troubleshoot electrical equipment without knowing they can safely do so

Are you familiar with PWM? Pulse width modulation type circuits?

 

1) are any fuses popped?

2) are any component heating up ?

3) under load is it generating power?

4) are there any fault indicator lights or sounds?

5) does it have online connection for diagnostic software?

6) is there a burnt smell, sweet or otherwise?

7)what is it doing as opposed to not doing?

8) do you see any visual indications of component damage?

9)Do you have the users and manufacturers manual?

10) have you contacted the manufacturer for advise?

 

Those questions are safe to check.

(Oh on the visual checks, do any capacitors appear deformed? If you don't know how to recognize a capacitor. STOP NOW. Let a professional repair. Before you kill yourself.

Agree but I am curious to learn.

No. Only tester, screw drivers and hand tool. As already told Studiot, I only have maximum 600 watts load for this stabilizer right now.

I am sorry to make you uncomfortable but I do not touch things without having proper knowledge.

No not familiar with PWM.

Your not providing any details where we can help. Look for a nameplate info sticker make and model number please

Unfortunately, I do not have this stabilizer packing as I purchased it in 2010. The only info I can find on it`s body is here

I am trying very hard to help, but your linked page about the inverter leads to a virus infected webpage, infected with the Google Survey Scam.

 

 

You really need to explain properly what your issue is and why you have apparantly connected the outputs of two electrical devices together in opposition.

I am really sorry about that page but that page works fine at my end. You can see that inverter details by watching and seeing this photos

My issue is that I am not getting consistent 220 V and stabilizer`s output voltage is same as input. Not sure what do you mean by "why you have apparantly connected the outputs of two electrical devices together in opposition"? I tried to power inverter from this stabilizer so that it can get 220 V but as inverter lcd show voltage is not 220 V.

After a glance at pictures... It bothers me that the transformer just looks too small for 2500VA (but it is hard to say because there is not much to be used for scale). I hope I am wrong; because if the transformer is substantially weaker than 2500VA, then there is probably nothing you can do.

 

Hmm... If this is a 'constant voltage transformer' technology then I would expect to see some more substantial capacitors (but I never meet such technology, so again I could be wrong). So it seems to me that this is just a multi-tap transformer and two relays to choose taps.

As written on it`s body front it should be 4166.666666666667 VA as I know that 1000 VA = 600 watts and it is 2500 watts. I need to run 1000 VA inverter on this stabilizer so I am fine even if it`s capacity is half than mentioned on it.

Yes I also believe that it is a relay type transformer as people on one of Pakistani forum told me.

What makes you think it is broken?

 

Many such pieces of equiment wil only turn on under load.

Have you tried it on load?

 

 

This could be very dangerous if you lack experience.

Not exactly sure what do you mean by broken? I believe it has fault because as shown on it`s front , It must get 90 - 250 VAC and must output 220 V but it`s not doing that. It`s output is same as the input or even less than input.

Sorry but again I am not exactly sure what do you mean by under load and on load. I am trying to run 600 watts Inverter on it and it can support up to 2500 watts but I currently do not have more load for it.

Yes, I know this is dangerous. I even got shock 2-3 times while trying change amperes on it`s circuit to get 220 V. Please see this to know how I was increasing amperes. I was taught increasing amperes by one refrigerator repair person.