Login | Register
The Engineer's Place for News and Discussion®

Previous in Forum: % Impedance In 3-Phase Transformer   Next in Forum: Idle Power Supply Energy Consumption
Close

Comments Format:






Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







36 comments
Associate

Join Date: May 2008
Location: Mauritius
Posts: 25

Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/20/2012 10:59 AM

According to a Russian Power Saver designer, he claimed that by using anti-parallel or back to back connection of SCR after the kWh meter, 30% of energy can be saved.

In his design, he has used two thyristors 25A (T122-25-3), 2 NTC Thermistors 120 ohms, 2 electrolytic capacitor 470uF 10V and some basic components such as 4 diodes as a bridge, one potentiometer 10K, 2 bulbs 60W in parallel and one capacitor 6.8uF 32V plus a brushless fan 12V 100mA to cool the thyristors.

Is there an electrical theory to back him in his design or it is simply SCAM!!!

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 10102
Good Answers: 333
#1

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/20/2012 11:41 AM

Sounds very scam-like. Can you post a link?

__________________
A nap would have been more productive. ©ER
Register to Reply
Associate

Join Date: May 2008
Location: Mauritius
Posts: 25
#2
In reply to #1

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/20/2012 11:47 AM
Register to Reply
Guru
Hobbies - Fishing - Old Salt Hobbies - CNC - New Member United States - US - Statue of Liberty - New Member

Join Date: Mar 2007
Location: Rosedale, Maryland USA
Posts: 3968
Good Answers: 180
#3

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/20/2012 12:14 PM

Soft starter for the home? To control current surges for all the devices. A lot of bills have peak usage charge. The maximum watts drawn in anytime of the bill period for some time frame like 15 seconds. The utility company uses it figure stand by power. And you pay for the ability to have the power available. It's one of the surcharges. Lowering it would save cost.

__________________
Life is not a journey to the grave with the intention of arriving in a pretty, pristine body but rather to come sliding in sideways, all used up and exclaiming, "Wow, what a ride!"
Register to Reply
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 10102
Good Answers: 333
#5
In reply to #3

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/20/2012 12:18 PM

Might possibly save a bit on the bill (where that kind of billing is used). That's a long shot from saving kWh.

__________________
A nap would have been more productive. ©ER
Register to Reply
Associate

Join Date: May 2008
Location: Mauritius
Posts: 25
#6
In reply to #5

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/20/2012 12:26 PM

Do you know any Power Saver on the market or Power Saver schematic diagram which REALLY save energy?

Register to Reply
3
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 10102
Good Answers: 333
#9
In reply to #6

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/20/2012 2:17 PM

No. However, efficient power supplies, correctly set thermostats, turning off unnecessary devices etc. will save energy.

__________________
A nap would have been more productive. ©ER
Register to Reply Good Answer (Score 3)
3
Guru
United States - Member - New Member Engineering Fields - Power Engineering - New Member

Join Date: Sep 2006
Location: California, USA, where the Godless live next door to God.
Posts: 3428
Good Answers: 464
#10
In reply to #3

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/20/2012 4:14 PM

"A lot of bills have peak usage charge. The maximum watts drawn in anytime of the bill period for some time frame like 15 seconds. The utility company uses it figure stand by power. And you pay for the ability to have the power available. It's one of the surcharges. Lowering it would save cost."

Not really applicable.

Residential customers do not pay Peak Demand Charges anywhere I know of, that is only true for large commercial and industrial customers, and it requires a different kind of metering system than what it used in residential accounts. The claims in this scam (and yes, it is a scam) are for residential users. Plus, the demand window is usually 15 MINUTES, not 15 seconds. I've seen longer demand windows, i.e. 20-30 minutes, but never shorter than 15 minutes.

This "device" has a single purpose: to separate fools from their money. The CONCEPT looks to be based on a very old circuit design from the 1970s called the 'Nola Circuit", and if you do a search on it you will see a similar setup. The purpose was for a SINGLE AC motor controller that might run UNLOADED for some reason for at least 50% of the time. When the motor is unloaded, the SCRs are phased back to reduce the voltage a little, which drops the watts looses in magnetizing the motor. It ALSO drops the motor torque, but remember, it is only intended to engages when the motor is unloaded, so therefore the torque is unnecessary anyway. it technically works, but the savings are small and TOTALLY dependent upon the motor NEEDING TO RUN UNLOADED. Most of the time, the Off switch is a much better way to accomplish that!

Trying to assert that this concept will do anything of value in a whole-house installation is absolutely preposterous, and most likely dangerous for any electronics that are connected to it. STAY AWAY!!!

__________________
** All I every really wanted to be, was... A LUMBERJACK!.**
Register to Reply Good Answer (Score 3)
Associate

Join Date: May 2008
Location: Mauritius
Posts: 25
#11
In reply to #10

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/20/2012 5:06 PM

I can confirm that the Demand windows in my country is 30 minutes.

Register to Reply
Power-User

Join Date: Dec 2006
Posts: 347
Good Answers: 6
#16
In reply to #10

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/21/2012 6:16 AM

jraef; very good answer! perry

Register to Reply
3
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 10102
Good Answers: 333
#4

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/20/2012 12:15 PM

Here's the circuit:

Can't see any reason why it would do anything but waste power.

__________________
A nap would have been more productive. ©ER
Register to Reply Good Answer (Score 3)
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Ketchikan, AK, USA
Posts: 12931
Good Answers: 463
#8
In reply to #4

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/20/2012 2:14 PM

The word MINIMIZATOR is a dead giveaway. Right up there in "turbo encabulator" territory.

__________________
In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply
Guru
Canada - Member - Specialized in power electronics

Join Date: Feb 2008
Location: Montreal, Canada.
Posts: 1192
Good Answers: 75
#27
In reply to #4

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/21/2012 10:31 AM

If you unbalance the SCR firing, you draw DC current that is not measured by the meter and can even act as a brake for the meter's rotor.

This DC current is fine for you strip heater and incandescent lights.

It is not good for the induction motors and definitively bad for the utility distribution transformer.

Totally illegal with big liabilities...

__________________
Experienced is earned, common sense is taught, both are rare essentials of life.
Register to Reply Score 1 for Good Answer
Associate

Join Date: May 2008
Location: Mauritius
Posts: 25
#29
In reply to #27

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/21/2012 12:29 PM

Will the SCR firing unbalance if one of the NTC thermistors is changed to 200 ohms for example?

Register to Reply Score 1 for Off Topic
Guru
Canada - Member - Specialized in power electronics

Join Date: Feb 2008
Location: Montreal, Canada.
Posts: 1192
Good Answers: 75
#31
In reply to #29

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/21/2012 2:52 PM

I think that they are gate protections from overvoltage. Not likely to be a temperature control point.

__________________
Experienced is earned, common sense is taught, both are rare essentials of life.
Register to Reply
Guru

Join Date: Jun 2009
Location: South of Minot North Dakota
Posts: 3909
Good Answers: 360
#7

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/20/2012 1:43 PM

The most effective way I have found to save energy in my home is to get after my wife about not having the doors and windows open while the heat or air conditioning (or both a the same time.) is on or driving to town and spending $10 on gas to buy a $1 item then come home or leaving the TV and sound system and every light on in the house 24 hours a day.

Yep I am married to a 36 year old 4 year old.

__________________
I'm not just a Jerk. I'm a Jerk with a big honkin calculator!. - tcmtech.
Register to Reply
Power-User

Join Date: Jan 2011
Location: Indiana
Posts: 167
Good Answers: 7
#13
In reply to #7

Re: Can anti-parallel or back to back connection of SCR saves kWh?

10/21/2012 1:43 AM

Don't feel bad tcmtech I married a collage educated woman who manages multi-million dollar funds for her company, and she can't even keep track of her own bank account.I usually have to wind up putting money in her account every other week. And yes you are very correct in the respect that they are 4-5 year olds when it comes to turning off vampire/phantom energy where it exists. like the TV,Radio,AC with windows open, fans when there is no one home, and all of the other energy wasters out there. They just seem to think we can fix anything including printing money. Just to say it anyway my printing press is BROKE. And so am I. Duke P.S. I just have to say it and I might wind up with a knot on the top of my head, oh well here goes. But how many years are they going to try and fool us into thinking they are 21 and holding. Now I have to go hide in the shop till she cools down, maybe I will go back in the house tomorrow. Duke

Register to Reply Off Topic (Score 5)
2
Power-User

Join Date: Jan 2010
Location: Atchison Village
Posts: 274
Good Answers: 21
#12

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 12:34 AM

Pardon my dumbitude, but how does current flow in this circuit? Looks like a total fake. Everything is connected to the same point. Where does the voltage occur?

Is there some convention in Russia I'm missing?

__________________
Align culture with nature...
Register to Reply Good Answer (Score 2)
Guru

Join Date: Dec 2005
Location: Wisconsin USA
Posts: 823
Good Answers: 34
#14
In reply to #12

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 4:18 AM

I believe that you are 100% correct. There is no break in the top line; there is no break in the second line. Although many components are connected to that second line, in all cases, it is BOTH ENDS of those components. They will all be at the same potential and thus have no current flow. GA from me.

__________________
" Ignorance and arrogance have more in common than their last four letters. "
Register to Reply
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 10102
Good Answers: 333
#18
In reply to #14

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 8:40 AM

It's not that trivial. How about this arrangement?

If the input was a 230Vac sine wave, would the voltage waveform at the output side be the same (given that a load was connected)?

[Note: I am in no way supporting the claim that the circuit can save power]

__________________
A nap would have been more productive. ©ER
Register to Reply
Guru

Join Date: Oct 2007
Location: India
Posts: 1272
Good Answers: 33
#20
In reply to #18

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 9:02 AM

My dumb answer is no. The out put voltage will be reduced by an amount equal to the diode junction voltage drop. There will be some waveform distortion at the time of diode switching crossover.

Register to Reply
Power-User

Join Date: May 2010
Location: NYC
Posts: 452
Good Answers: 11
#26
In reply to #14

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 9:50 AM

I beg to differ with your response.... It may be true that the circuit is not doing any real energy savings but no matter how insignificant the energy that can be salvaged, it is something!

I think the circuit will behave as follows!

1. Any load that gets connected at the right end of the circuit, will make the circuit complete and therefore current will flow..

2. Depending on the type of load plugged, if mostly resistive in nature like a heaters or incandescent bulbs, there will be no reaction since the voltage and current remained in phase.

3. If the load becomes mostly inductive as in motors, it will change the overall circuit's behavior, since some phase difference, harmonics will be introduced due to the inductive nature of the load..

4. At this point, whatever phase difference presented in the circuit will cause an equivalent unbalanced in the current passing on the neutral wire which is now considered as a wasted energy since it will ultimately be sinked into the ground or earth potential without those thyristors in place!

5. But with the thyristors in placed, it will react and behave differently to whatever unbalance current it senses along that neutral wire. It will divert whatever current difference sensed before it got dump to the earth ground and used that salvaged energy to drive the small fan in the schematic!

I maybe wrong in my thinking so pls. correct me!

__________________
Anything is possible?
Register to Reply
Guru

Join Date: Dec 2005
Location: Wisconsin USA
Posts: 823
Good Answers: 34
#30
In reply to #26

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 2:11 PM

Are we all seeing the same circuit diagram, and has there been any editing or change in it? I did NOT see T1 when I studied it yesterday, or I would not have said that there's no break in the second line. Don't see how, but maybe I just missed it. I also cannot see any neutral wire now, nor did I then, and whatever it says at the left end of both lines is too blurred to decipher, so . . . maybe one of them is supposed to be neutral? Or are we supposed to ASSUME that there is one, though not in evidence, or to consider neutral = ground side? Old houses around here were wired with ONLY two conductors to each point, with no direct ground; a few areas of my house are STILL that way, because I'd need to tear out part of a wall to change it. Original wiring done in 1927, if penciled notes next to the four 15-amp fuses are correct. Hence, I don't normally assume that there will be power ["hot"], ground, and neutral all present unless explicitly shown to be so. My bias; your results may differ.

__________________
" Ignorance and arrogance have more in common than their last four letters. "
Register to Reply
Power-User

Join Date: May 2010
Location: NYC
Posts: 452
Good Answers: 11
#32
In reply to #30

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 3:17 PM

The circuit as shown in post #4, posted by JohnDG, is a magnified version of the circuit described by the OP. I hope /believe that we are on the same page, looking on the same schematic as the subject our comments!

I'm sure you are very much aware, that with regard to the 120 V power distribution in our houses, nothing has really changed much in the house wirings since Edison's time. Except for the "recent" addition of a 3rd wire called / labeled as 'ground', which was done for safety reasons only..applicable on newer constructions or when remodeling..

Residential 120 V systems can be either a 2-conductor (old house) or 3 conductor system (in newer constructions). The power carrying conductor has always been considered as 'hot', while the second conductor is called 'neutral', which always serves as the circuit's the return path back to power source.

__________________
Anything is possible?
Register to Reply
Guru
Canada - Member - Specialized in power electronics

Join Date: Feb 2008
Location: Montreal, Canada.
Posts: 1192
Good Answers: 75
#33
In reply to #32

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 6:08 PM

Vsar. You wrote: "nothing has really changed much in the house wirings since Edison's time"

You certainly meant Tesla. Edison was a proponent of DC current distribution that failed miserably ... (It may come back once the technology is ready).

By the way, current going to the neutral conductor and eventually the ground is not wasted. It is a necessary path to complete the circuit. I suggest that you revise the circuit theory before trying to teach others.

You claimed that the inductive loads produce harmonics. Not usually true. It is mostly the semiconductors and other active devices that produce harmonics. In this case, the thyristors when they are not firing fully.

Under full firing, the load voltage will be very similar to the AC line as correctly posted by Joshi and incorrectly argues against by you. The ~1V drop in the SCRs is almost negligible.

You said that "any energy saving is good". That is not generally true if achieved at the expense of reliability, increased losses at the load, and payback period that extend beyond the useful life of the circuit.

I believe that in most case, this circuit fails the above criterion.

I hope that I am not offending you with this response. Have a nice evening!

__________________
Experienced is earned, common sense is taught, both are rare essentials of life.
Register to Reply Score 1 for Good Answer
Power-User

Join Date: May 2010
Location: NYC
Posts: 452
Good Answers: 11
#34
In reply to #33

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/22/2012 12:26 PM

Mr. Marcot,

Please re-read my original response as posted @#26, up to its last word.. Please take the whole thoughts, not just some words from it! Also while reading, bear in mind English is not my native tongue!

Regarding Tesla or Edison, sorry it has been so many years since...nowadays my brain only works part time...

This forum actually helps me remember, reminding me of some technical stuff I used to or did during my younger productive days!!

Thank you!

__________________
Anything is possible?
Register to Reply
Associate

Join Date: May 2008
Location: Mauritius
Posts: 25
#24
In reply to #12

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 9:34 AM

May be when the circuit is closed with the load. The potential difference across the thyristors is the source of power. I think we should design one and do some tests.

Register to Reply
Guru

Join Date: Oct 2007
Location: India
Posts: 1272
Good Answers: 33
#25
In reply to #24

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 9:43 AM

" I think we should design one and do some tests."

Go right ahead! Pray, who are these WE, you are counting?

Register to Reply
Associate

Join Date: May 2008
Location: Mauritius
Posts: 25
#28
In reply to #25

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 12:12 PM

Unfortunately, I could not find the thyristors and 120 ohms NTC THERMISTORS on the local market. I have even searched on Ebay but in vain.

Register to Reply Score 1 for Off Topic
Guru

Join Date: Oct 2007
Location: India
Posts: 1272
Good Answers: 33
#15

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 5:55 AM

The only and guaranteed way, to bring down your bill $$$ is to switch off, what you don't need, at any given time.

Register to Reply Score 1 for Good Answer
Participant

Join Date: Oct 2012
Posts: 1
#17

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 7:05 AM

What is the use of 2 x 60 w. Bulbs, how it saves energy.

Register to Reply
Associate

Join Date: May 2008
Location: Mauritius
Posts: 25
#22
In reply to #17

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 9:23 AM

I think the bulbs are for limiting the current before supplying the brushless fan -12VDC 0.1A

Register to Reply
Power-User

Join Date: Jan 2006
Location: Tamworth, UK.
Posts: 427
Good Answers: 4
#19

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 8:50 AM

Perhaps it is a device to set up circulating harmonics that interfere with the meter causing it to run slow. It might save money but not power.

__________________
If you haven't made a mistake; you haven't made anything.
Register to Reply
Associate

Join Date: May 2008
Location: Mauritius
Posts: 25
#23
In reply to #19

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 9:28 AM

I also think that this circuit will generate harmonics and will slow electromechanic type kWh meter. Power will not be saved but on the other hand kWh registration will be affected.

Register to Reply
Guru
Hobbies - DIY Welding - New Member Hobbies - Target Shooting - New Member Engineering Fields - Civil Engineering - New Member United States - Member - New Member

Join Date: May 2009
Location: Red Hook, New York (Mid-Hudson River Valley)
Posts: 3722
Good Answers: 125
#21

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/21/2012 9:19 AM

This ranks right up there with "Unattainium"....

__________________
"Veni, Vidi, Vici"; hendiatris attributed to Gaius Julius Caesar, 47 B.C.
Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing. Kettle's on.
Posts: 19612
Good Answers: 472
#35

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/23/2012 6:23 AM

<sniff, sniff>

Dog?

<sniff, sniff>

Cat?

<sniff, sniff>

Bull?

__________________
There was a time, not long ago, when people were smarter than their phones... (tips hat to CR4 user Harley.)
Register to Reply
Power-User

Join Date: Dec 2010
Location: 1° North Singapore
Posts: 467
Good Answers: 15
#36

Re: Can Anti-Parallel or Back to Back Connection of SCR Save kWh?

10/27/2012 11:35 PM

What this circuit does is to introduce a delay turn-on at the beginning of every half cycle. If you look at the waveform, it will not be complete AC cycle , but 'chopped' at beginning of the AC cycle.

1. The RMS voltage of this chopped waveform is reduced , more delay will cause more reduction. Any load connected to this supply will draw less power. THis is the trick many salesmen use to give immediate comparison, switching in and out this circuit.

2. The two SCR , due to imbalance in triggering , will generate unequal delay turn on, this will generate DC and high harmonics in the supply line. Any electrical load which make use of AC magnetisation, e.g., induction motor, transformer, fluorescent lamp ballast will experience overheating due to DC and high harmonics component in the supply. More imbalance, more overheating. A severe imbalance will even cause current spike in load current due to magnetic component core saturation.

3. It will be delicate to ensure both the positive and negative half cycle are tuned to have equal delay turn on. Power supply company has very stringent requirement on this unbalance ( I think it is less than 1%)

An interesting point raised by Marcot, if the DC generated by the imbalance of positive and negative cycle will cause brake on the meter rotor motor, then there is a possibility that the energy meter may have errorneus (lower ) measurement ! Anyone know what is the working principle of traditional analog energy meter ?

__________________
Sharing knowledge is one thing that defies basic arithmetic logic --- the more you share, the more you get!
Register to Reply Score 1 for Good Answer
Register to Reply 36 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

bravo88 (1); CaptMoosie (1); horace40 (1); JohnDG (5); joomunm (8); Joshi (3); JRaef (1); Kishor Parikh (1); LOCKDUKE (1); marcot (3); ormondotvos (1); ozzb (1); perry (1); PWSlack (1); Ron (2); tcmtech (1); Tornado (1); vsar (3)

Previous in Forum: % Impedance In 3-Phase Transformer   Next in Forum: Idle Power Supply Energy Consumption