Vphase units

[spark 68]

Hi Marvo,

Please correct me if Iam wrong, but don't motors pull more current when under run ?, this is a genuine question, and I will stand to be corrected.

 

[Marvo]

The efficiency and power factor may change for the worse at low voltages but if the motor is designed for EU usage (220v) then these effects should be negligible.
Apart from that the run current would decrease if the voltages decreased from >240 to 220.

Why do you think they might run at higher current?

 

[spark 68]

Why do you think they might run at higher current?

I remember reading about it somewhere, where it was considered bad practice to under run motors, as they would pull more current and could cause damage to the windings, hence the VSD type drives which doesn't alter the voltage, just the frequency and time on/off (mark/space ratio).

 

[Marvo]

If the voltage drops sufficiently, ie probably <200v, it could cause lots of problems which would be mostly because the motor efficiency plummets, losses snowball and overeating follows.

 

[ipf]

Let's all talk about the cost affectiveness of wind farms.

 

[Engineer54]

Let's all talk about the cost affectiveness of wind farms.

Let's NOT!! ...lol!!

 

[ipf]

Let's NOT!! ...lol!!

ok then

 

[Knobhead]

Sorry Marvo, but a motors output at the shaft is governed by the load. Lower the voltage and the current goes up. Your bucket full of water requires the same power to fill it no matter which way you supply it. If the pump speed is varied efficiency is altered. So I’m afraid pumps are not a good example, not many small motors are.

 

[UNG]

The unit provides an output at an optimised voltage which is less than the usual supply voltage. How it does it is immaterial. Your question does however make me wonder what the losses are through this unit.....but I digress.

Here's the math as I see it;

If my irrigation pump and my swimming pool pump are both 1 kw and they're set to run sequentially without overlap and both run for 5 hours each.
If my usual voltage is 247 as someone stated previously and the vphase reduces this to 220v Then the drop in supply voltage will cause a corresponding drop in run current which equals a drop in energy consumption. If the drop in energy consumption is 10% after efficiency considerations then it will save roughly 0.1KW for 10 hours which is 1 KWh.

Any drop in voltage will result in an increase in current so how it does it is relevant. Going back to basics the only constant value in a circuit is resistance, having done a quick calc 244v x16A = 3904w if you assume the current remains constant then reducing the voltage by 10% results in 220v x 16A = 3520w a 10% ish reduction in the watts used, physics bending at work I think

Very much so. As I said there would need to be strict criteria involved to achieve energy savings the might be worthwhile.


Don't know the answer to question 1 but I have a borehole pump, an irrigation pump and a pool pump so I would qualify as having a considerable motor element to my electrical load.

When I say 'install correctly I should have said 'install it in the optimum configuration so it supplies appropriate loads.'


I doubt I'll convince you to fit one cause I don't think I'd convince myself to fit one either. To be honest I don't know what price they retail for and I'm even more clueless on how much it would cost to install.
The actual savings would be very difficult to assess accurately as previously pointed out.
All I'm saying is the broad theory behind voltage optimisation works, realistically I think they may have a niche market in new build projects but I wouldn't like to have to sell them to Joe Public in large numbers.

As I have said in previous posts the criteria used to show savings is flawed

Judging by your last few sentences your not as convinced as you appeared to be earlier.
If the broad theory behind voltage optimisation / reduction works then can someone explain how the practical side works.
If fitted on new builds you would not know whether it was saving you anything or not so it could be a white elephant on the wall.

 

[sbrown2]

Can I ask what theory this V phase unit works on? All of the other theories relating to current, voltage, frequency and phase angle have been covered. But what does this unit do?

 

[UNG]

Can I ask what theory this V phase unit works on? All of the other theories relating to current, voltage, frequency and phase angle have been covered. But what does this unit do?

Answers on a post card please or is it that the answer could be put on a postage stamp

 

[Marvo]

Sorry Marvo, but a motors output at the shaft is governed by the load. Lower the voltage and the current goes up. Your bucket full of water requires the same power to fill it no matter which way you supply it. If the pump speed is varied efficiency is altered. So I’m afraid pumps are not a good example, not many small motors are.

Lol, please don't appologise, you're theory is spot on, I was just trying to avoid getting too deep into motor theory. The theory that low voltage is detrimental only applies once you're no longer running the motor in full flux saturation. My theory was that this wouldn't be the case if the motor was developed to run on EU supply.

As pointed out if the voltage decreases below a certain point it would result in lower flux and therefore loss in torque leading to high slip or stall and overload. Where I was thinking is that if the motor is designed to operate on EU voltages then it would still run in full saturation at a voltage that's 'optimised' from 247 to 220v and possibly a little lower. In actual fact it would be slightly oversaturated at UK voltages with some I²R losses. If this were the case then there would be an energy saving.

Yeah yeah I know I'm flogging a dead horse, the more look at this the more it looks like savings would be marginal and many of them might be at the expense of something else. The reason I'm not opposed to the general theory behind it is I've experienced voltage optimization setups in the industrial sector and there are large energy savings to be had same as there is with power factor correction. I can see there could be some savings to be had but I agree it would need to be specified on a case by case basis.

 

[malcolmsanford]

Marvo I'm sure SA is the same when your in a hole you can't get out of the last thing you need is a .......shovel lol

 

[Marvo]

Aww c'mon,:rofl: I'm not writing anything off...even snake oil as somebody called it.... without exploring it fully. You're right though, I'm just about at the stage where I'm playing devils advocate on this one. We can't even use the optimisers here cause our voltage is 220v on a good day, usually nearer 200 in peak periods.

 

[Marvo]

This artical made an interesting read. http://itee.uq.edu.au/~aupec/aupec04/papers/PaperID77.pdf

Does anyone know if the results of the Ofgem Scottish Energy Trials have been released yet? Link

 

[Knobhead]

I hate to point this out Marvo but a quick glance at the first paper covers RAISING the voltage in Australia.

Sorry again :rofl:

 

[Big n Daft]

Good lord, you lot still at it.

 

[Marvo]

I hate to point this out Marvo but a quick glance at the first paper covers RAISING the voltage in Australia.

Sorry again :rofl:

It's looking at the effects of operating domestic appliances at different voltages.

Good lord, you lot still at it.

I'm trying a new tactic now. If the thread runs long enough I'm hoping Tony will install one at his house and let us know how much he saves.

 

[Knobhead]

Marvo, I might be big (6' 2") but I'm not daft!

 

[topquark]

This artical made an interesting read. http://itee.uq.edu.au/~aupec/aupec04/papers/PaperID77.pdf

Does anyone know if the results of the Ofgem Scottish Energy Trials have been released yet? Link

Pretty much what you'd expect, even with upside down electrons

 

[Sam the man]

How about the VO4Home unit, that looks better but its £600!

 

[UNG]

Better than what!!. Can't be bothered to look. The only thing I see is a better rip off at £600 and an even longer payback

 

[Guest111]

Now here’s a strange twist, we’re now joined by Gordon0707. Zero posts, but a thanks to P Clark for his defence of the “snake oil” unit.

Has my mind become that nasty and suspicious?

NO,I told you that in our phone conversation did I not? your,e just turning into an old meldrew like me,btw you done anything about the meldrew lounge yet? lol

 

[Guest111]

Ha I,ve got it finally and you are all way off the mark,obviously the unit does bugger all worth laying out that kind of money for and the sole reason for its existance is as follows, A to make the manufacturer money and B to give us lot on here something to get heated over on a regular basis :teeth_smile:

 

[UNG]

and B to give us lot on here something to get heated over on a regular basis :teeth_smile:

So there are savings to be made we haven't even bought one but we get heated by it:biggrin::biggrin:!!

 

[Knobhead]

I’ll be honest, if someone offered one on a trial basis, I’d happily give it a whirl. If nothing else it would set my mind at rest. But how do you set up a definable test procedure in a domestic property?
A company I used to deal with have had a 400KVA unit fitted. They weren’t happy when I said all they needed to do was turn the 11/.44KV off load tap changer down 2.5%. In the foundry I dropped the voltage to one plant after we had trouble with voltage regulation at the weekend toasting VSD units.
With domestic supplies the distribution transformers aren’t fitted with tap changers. But the 33/11KV grid units have on load tap changers, it’s just a case of entering a new base value. But that would reduce demand and therefore profits.

 

[Knobhead]

Brussels will not be happy until we’re down to 380V. I’ve worked on a plant that had two systems 433V and 380V what a cock up but the manufacturers of the printing machines would not guarantee the gear at the higher voltage.

The first plants I first worked in were all 550V. I helped put in the first of these weird 440V transformer things, after that it degenerated in to bedlam. As plants spread out the distribution systems over lapped. All 550V transformers had reverse phase rotation (a hangover from our own power station) then some loony decided new 440V transformers should have forward rotation. To totally confuse the situation I installed 5off 11/.44KV transformers in a plant that was mainly 550V, the powers that be decided the phase rotations should match.
So we had:
550V reverse
440V forward
440V reverse
I miss the place like I miss toothache!

 

[yorkshiremike]

If it's any help,I've had a VPhase installed for the last 6 months - I didn't pay for it as such- was installed 'free' as part of a PV install.
Installation – It was possible on existing CU only because there was space andCU is a recent 16th/17th edition upgrade with several RCBOs. It was necessary to make a 3rd break in busbar so that the VPhase supplies the RCD block (upstairs and down stairs rings)and a block of mixed RCBOs (kitchen sockets, bathroom lights) and the non-RCD(smokes, downstairs lights), with the third (unregulated) block (most RCBOs)consisting of shed, oven/hob, PV and the feed to the VPhase.
The installation instructions for the VPhase state that it should not be usedto control any thermostatically controlled heavy heating loads (e.g. electriccookers, immersion heater, electric shower) and no heavy machine tool loads(presumably no big motors because of in rush currents?).
Out of the 40+ CUs I've seen in the last 4 months (when doing PV installations)there have only been 2 that would have allowed a fairly straight forwardinstallation.
Operation:
The spec says that the VPhase can regulate up to 20amps on a short termbasis, but I've never seen 4kW on mine before it bypasses. Practically, thismeans that any 2 high loads (e.g. steam iron + kettle) will send it temporarilyinto bypass. The VPhase is meant to be able to regulate at 8amps continuously(above this it gets too hot and goes into bypass). This seems about correct -on my unit it can regulate a 1.5kW load continuously, at 2kW after about 1 hourthe case temperature is 45+ degrees and the unit goes into bypass for about 10minutes then regulates again for about 40 minutes etc.
Losses in unit:
The spec says the VPhase losses are less than 1%. On my unit at a 2kWregulated load, the unit is consuming about 25W, so this seems about correct.However, it looks like it has a base consumption of about 10W-15W, so even atnight when the 'background' load is about 40W, the VPhase is consuming 25% ofthis.
Energy savings:
Equipment with universal electric motors in(vacuum cleaner, food processor, fridge etc) really do show reduced consumptionin the order of 18-20% (mains at 238-242V vs regulated 219-220V from VPhase).However, that's not the whole story. It's evident (change in pitch when switchbetween the 220 and 240) that the motors are running slower. It doesn't make much difference to how wellthe vacuum cleaner works, but although 'instantaneously' when the fridge/freezermotor is running it shows a 19% improvement, if I monitor the consumption overa week on 220V then on 240V the lower voltage only results in a 5% saving.Presumably because the fridge motor needs to do a certain amount of workcompressing the refrigerant and just runs for longer when the voltage isreduced.
As has been previously said, it makes no difference to any thermostaticallycontrolled heaters, they just run longer, i.e. takes exactlythe same number of Wattsxtime to boil the kettle or toast the bread. It looksthough like the microwave takes about 4% less energy to boil a cup of water at220V (takes a bit longer, but less than 10% longer and power consumption is 15%less).
White goods (dishwasher, washing machine)don't show a significant improvement <5%, I presume because most of energyused is in heating water, which isn't affected by voltage reduction - it's alsodifficult to do a consistent back to back test.
Lights - Most of my lights are LED, and Ican't discern any difference (either in brightness or energy consumption)running at the regulated 220 or 240V but the LEDs' consumption are close to theresolution/sensitivity of my test gear. The few halogens, consume about 15%less but are noticeably dimmer. Interestingly I tried an old (notelectronically regulated) fluorescent strip light and it showed both a 20%consumption improvement and no change in light output.
Electronic goods - Most of the stuff I havehas switch mode PSU (LCD TV, radios, computers, printers etc) and there's onlya very slight improvement running on a regulated 220V certainly less than 5%,seems to be about an average 2%.
Gas boiler - The peak electricity load (CHpump + flue fan) reduced by about 15%, it's possible that the pumps and fansrun longer to compensate, but I couldn't tell.

Conclusion: I've a fairly low electricityconsumption (8kWh per day, house occupied all day), and I make it that theoverall costs are somewhere between -£15 and +£5 (i.e. might cost an extra £5through to saving a maximum of £15), which equates to a maximum possible savingof about 3%. But, for example our lighting consumption is now 10% of that usedcooking, whereas before fitting the LEDs it was nearly the same and the newFridge Freezer uses 1/3 the power of the old one (which was the single biggestconsumer). So I would imagine it's possible if had an older F-F, lots ofhalogen/tungsten or fluorescent lights to see a saving over 5%.

 

[UNG]

Still not convinced and your post makes me even more suspicious of these units

 

[Knobhead]

As I’ve said before if someone offers one on trial for free I’d give it a whirl. But I’d be a very sceptical person to convince. The inherent losses are my main concern.

 

[UNG]

As I’ve said before if someone offers one on trial for free I’d give it a whirl.

It would still be to expensive for me, even getting it free I don't think they are worth the time, effort and cost to install

 

[Knobhead]

I’d want it fitted free!

 

[UNG]

You drive a hard bargain

 

[Marvo]

I think Yorkshiremike's analysis sounds well considered and fair. There are minor savings to be had but if you offset these against the fact it goes into bypass after load reaches 8 amps which would make the installation very tricky to get optimum results, the initial capital outlay, the less efficient running of certain appliances such as vacuum cleaners, fridges, lights etc....I can't help thinking it's just not a viable technology in your average domestic environment.

Maybe if you have an eco-house and have spent thousands on 300mm of roof and wall insulation, heat recovery HVAC systems, triple glazing and all that jazz then the VPhase might be justifiable as a final effort to squeeze every little bit of carbon out of your footprint.

If I wasn't on a different continent I'd seriously consider installing on of these in Tony's house. For entertainment value alone it would make it worth while.

 

[Knobhead]

I'm not paying for something i don't think will work.

Marvo, you'd have to put up with a grumpy old sod looking over your shoulder.

 

[Silly Sausage]

If they cut out after 8 amps, pointless Tony having one with his sound system (put it on 10 for a 4:30am start)

 

[UNG]

I think Yorkshiremike's analysis sounds well considered and fair. There are minor savings to be had but if you offset these against the fact it goes into bypass after load reaches 8 amps which would make the installation very tricky to get optimum results, the initial capital outlay, the less efficient running of certain appliances such as vacuum cleaners, fridges, lights etc....I can't help thinking it's just not a viable technology in your average domestic environment.

I think it shows how useless and ineffective this unit is

Maybe if you have an eco-house and have spent thousands on 300mm of roof and wall insulation, heat recovery HVAC systems, triple glazing and all that jazz then the VPhase might be justifiable as a final effort to squeeze every little bit of carbon out of your footprint.

But what carbon footprint does the manufacture of this unit create.

I don't worry about living carbon free as I keep generating carbon dioxide

If I wasn't on a different continent I'd seriously consider installing on of these in Tony's house. For entertainment value alone it would make it worth while.

What with a web cam feed I think it could be entertaining watching Tony with a sledge hammer

 

[Marvo]

What with a web cam feed I think it could be entertaining watching Tony with a sledge hammer

I think he's a softie at heart underneath the hard shell of an exterior lies a warm .........ah who am I trying to kid? He'd probably go at it with his steel toe-capped Doc Martens when his morning cuppa takes 45 seconds longer to make.

 

[Knobhead]

I’m not spoiling my 20 hole Doc’s kicking one of those things. Anyway who’s being spying on me?

 

[marzijac]

VPhase is inferior to both VO4Home and VoltisHome. The two latter units are rated for 60amps and both are one line in, one out so easier to install. Technically, the VO4Home is probably the better but overall, VoltisHome is probably the better choice simply because of size. The VoltisHome unit is far more compact and offers pretty much the same as VO4Home but at around £200 cheaper (though check the prices, they are subject to change).

 

[Engineer54]

Both unit's basically the same but one is 200quid cheaper than the other!! These units are beginning to sound very expensive to say the least. ...I wonder what the pay-back period is going to be?? lol!!!

 

[marzijac]

Both unit's basically the same but one is 200quid cheaper than the other!! These units are beginning to sound very expensive to say the least. ...I wonder what the pay-back period is going to be?? lol!!!

Well that's easy to work out. Each unit claims an 18% saving, unlikely but even if we take a lower performance level of 10%, then VoltisHome at £450 offers a payback time of less than 4 years, at £650 VO4Home offers a payback time of just less than 6 years. Obviously the payback times will be greater as the cost of electricity rises and/or the savings are greater than 10%. I've not heard anything about VO4Home but the VoltisHome unit as fitted by an friend was saving 14%. On an average utility bill of £1,200, that's a return of £168, or about a return of 37% on a £450 investment - can you get that much from a bank?

 

[Dan]

Just bumping some threads in the Electrical Wiring Theories and Regulations forum category here on our Electricians Forums. If this specific topic isn't current, just ignore it, it'll drop off the list in no time. However, if it's something you'd like to contribute to, feel free to reply and bring it back into current discussion.