Author Topic: Electricity getting very expensive in the Workshop  (Read 1555 times)

Offline awemawson

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Electricity getting very expensive in the Workshop
« on: April 26, 2022, 12:29:47 PM »
Today I replaced twelve 6 foot T8 70 watt fluorescent tubes with LED replacements. I have a total of 36 of the 6 foot tubes in the main workshop giving 2500 watts so with electricity having gone up to 29.49 p per kwH this was costing 75 pence per hour just to light - never mind actually using any machines ! My electricity for the workshop had been running at 8 per day (inc standing charge) so something HAD to be done.

The twelve that I have changed were a pilot exercise to check light quality etc, not a cheap exercise though at north of 150 for the LED tubes. If I can scrape any spare cash together I'll certainly do the other 24 as they are pretty good, and apart from access issues over machines were very easy to do - just replace the starter with a 'special' which actually is just a short circuit - then put the new tube in.

These ones are 24 watt so a saving of 66%

The welding shop foundry and woodwork shop probably have another at least 36 tubes between them which is why I've been putting it off - darn expensive this saving money lark!
Andrew Mawson
East Sussex

Offline RussellT

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Re: Electricity getting very expensive in the Workshop
« Reply #1 on: April 26, 2022, 01:21:29 PM »
I used to have a job trying to persuade businesses to use less energy because of climate change :bang: :bang: :bang:.  I think this would have been a good example - if it was used 8 hours a day 5 days a week the investment would be paid for in less than six months - most businesses would have managed that because they could do the investment from the fuel budget rather than needing to ask for funds from the boss.

For your workshop the hours of use will probably make it more difficult to justify, however adding switches and only lighting part of the workshop is likely to be even more cost effective.

Russell

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Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #2 on: April 26, 2022, 01:48:56 PM »
Yes Russell I have it wired in 'three banks' originally to distribute the load across three  6 amp MCBs each with their own three switches giving switching individually per group of four lights. (Big grid switch by the door)

The bank that I've done is the crucial one - it covers sink, loo, my desk, bench, and the CNC milling machine so that bank can remain one while the other three are in gloom !

Amusingly for some time I've had one tube that for the life of me couldn't get to strike up. and I was convinced that the ballast choke must be O/C - today I even dismantled the fitting to measure the choke (which was fine) only to find one pin on the original fluorescent tube  bent over at 90 degrees  :bang:
Andrew Mawson
East Sussex

Offline tom osselton

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Re: Electricity getting very expensive in the Workshop
« Reply #3 on: April 26, 2022, 04:24:12 PM »
Ive never regretted installing led lighting in the garage 

Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #4 on: April 26, 2022, 04:36:33 PM »
Well I've pushed the boat out and ordered another 24 LED tubes - bankruptcy here we come  :bugeye:
Andrew Mawson
East Sussex

Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #5 on: April 26, 2022, 05:24:27 PM »
Heck even I switched out my six 40 watt tubes for LED tubes in the larger shed. Lit maybe 200 hrs/yr.  It wasn't obviously the money driving it. I may never reach the payback period.

I just don't like the unnecessary energy usage, the mercury contamination, the slow start and unreliability in cold temps,  the short life and disposal problems of the old fluorescent tubes. It's a vast improvement any way you look at it.

But, I think halogen bulbs give a far better color spectrum than incandescent, fluorescent or LED bulbs -- at least from an artist's perspective.

LED's are improving that way, but you really have to look at the specs to tell if you're getting something pleasant to live with. fluorescent were generally poor that way as well, so for shop use, LEDs are no worse and might be an improvement.

I usually like a warmer light environment, so I go for the ~3000 - 3500 K +-  "soft white" types instead of the "daylight" types at 4000+ K, and look for 90 or better CRI (color rendering index) in the home so there aren't big holes in the color spectrum.

A few years years ago a local coffeehouse changed over to LED fixtures (with non-removable bulbs) -- talked into it by an electrician because their old incandescent ceiling fixtures and wiring were having ground problems. The owner was proud of the change, but after the change customers looked like walking cadavers, and the art shows on the walls might have been painted in gray tones. It was (and still is) an ugly light to sit in.
I love it when a Plan B comes together!
Steve
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Offline WeldingRod

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Re: Electricity getting very expensive in the Workshop
« Reply #6 on: April 26, 2022, 09:59:20 PM »
Another factor if you live in air conditioning country: you pay for the light then you pay to pump out the heat...  a 100 Watt light puts exactly 100 Watts of hear into your room!

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Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #7 on: April 27, 2022, 02:42:42 AM »
Ive recently swapped out over 50 GU10 halogen lamps for LED in the house. The saving with them is far greater than fluorescents as a 50 watt halogen replacement with approximately the same spectrum is only 5 watts. So only one tenth of the cost to run.

Anyone want a big pile of halogen bulbs and 6 foot tubes just ask!
Andrew Mawson
East Sussex

Offline hermetic

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Re: Electricity getting very expensive in the Workshop
« Reply #8 on: April 27, 2022, 04:09:01 AM »
Hi Andrew
  What are the current/induction implications of keeping the ballast in circuit? I must admit that offhand I don't know, but it would seem to be slightly counter productive, given that the driving current for the led's should be less than the tube current but perhaps enough to create some ballast losses? As my 8ft tubes fail I am replacing them with two 4ft led tubes held in the centre with terry clips and removing the ballasts, and it looks like they are producing similar light levels to the 2x8ft tubes they replace. I have found that 2x4ft led tubes can be had for much less than 1x8ft led tube! I am spoilt by the fact that when I put the lights in I used plug in ceiling roses and chain suspension, and that combined with my low ceiling means that they are really easy to get down, I imagine yours are a lot higher?
Phil
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Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #9 on: April 27, 2022, 05:11:14 AM »
Phil, yes the main workshop is high giving access issues, and the rows of lights are wired in plastic conduit running between beezer boxes on top of each light, the lights being chain suspended. This makes taking an individual light down quite difficult.

As for the ballast issue - I don't know the answer. I suspect that the current limit for the leds doesn't rely on the reactance of the ballast, as it would seem from the instruction sheet that it can be totally eliminated (with dire warnings regarding being a competent electrician!)

Turns out that I would need a further 41 LED tubes to replace all the 6 foot 70 watt fluorescent tubes that I have distributed between the welding shop, the foundry, the wood workshop and a Portakabin. This would be  a further 'investment' of 553.50 so that's NOT going to happen. I console myself with the fact that their use, unlike the main workshop, is pretty intermittent.

Scary to think that with the original 77 (total) 70 watt tubes there was 5,390 watts off lighting if all were on at once, which of course was actually never the case.
Andrew Mawson
East Sussex

Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #10 on: April 27, 2022, 08:11:37 AM »
I pulled the ballasts out of mine and wired direct to the tube holders. My tubes came with stickers to put on the fixture warning of the changed connection. Got a lot of electronic parts and copper wire for the scrap bin.

Of course I only had three of them!
I love it when a Plan B comes together!
Steve
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Offline Muzzerboy

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Re: Electricity getting very expensive in the Workshop
« Reply #11 on: April 27, 2022, 08:33:18 AM »
Last time I looked, the light output per W of drive was actually very similar for fluorescent and LED. Something like 100 lumens per Watt is typical for both modern LEDs and fluorescent tubes. On the face of it, replacing all of your tubes won't actually reduce your bills in the short term. They even claim very similar life for tubes and LEDs, possibly even longer for tubes. And yes, tubes lose output with time as they age and their voltage increases. But so do LEDs - they age and wear out too before finally failing.

Don't get me wrong. I'm an electronics engineer and I use LED lighting. I prefer to avoid glass tubes and mercury vapour for batten lighting. But being an engineer, I like to get my data right too!

The way the light output is defined / measured may differ between the 2 technologies but by and large, the numbers are going to be reasonably meaningful.

Here's some of the readily available options:
LEDs:
https://www.screwfix.com/c/electrical-lighting/light-bulbs/cat8350001?calclightbulbtechnology=led&cm_sp=managedredirect-_-lighting-_-ledbulbs
Tubes:
https://www.screwfix.com/c/electrical-lighting/tube-lights/cat2690010

Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #12 on: April 27, 2022, 09:04:46 AM »
On the face of it, replacing all of your tubes won't actually reduce your bills in the short term.

For these tubes the electrical consumption has reduced by 66% for an illumination that subjectively is better so I'm not sure what you're on about !
Andrew Mawson
East Sussex

Offline Muzzerboy

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Re: Electricity getting very expensive in the Workshop
« Reply #13 on: April 27, 2022, 01:05:10 PM »
Sorry I wasn't getting at you but I don't see the 66% improvement anywhere. The lumens per watt seems like a useful figure of merit.

What figures are you looking at here? I agree LEDs are a better solution but don't see how you'd save 2/3 of your electricity costs.

Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #14 on: April 27, 2022, 01:27:16 PM »
Seems odd to me. I agree with Andrew that the light level seems equivalent or better with the LED tubes than it was with the fluorescents. So much so that I now am using a single tube in each fixture instead of two.  The Parmida brand tubes I use are rated at 2200 lumens on 18 watts.

Also you might consider that the illumination is directional on an LED tube, even a frosted one, while it isn't on a conventional fluorescent tube. So the lighting is more effective in the downward direction. Thus effective light levels may be higher.

By reducing the number of tubes there is an additional savings.
I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #15 on: April 27, 2022, 01:44:36 PM »
Checking for similar daylight fluorescent tubes I get 3,000 lumens average on 40 watts. That's 75 lumens/watt.

For the Parmida tubes it's 2200 lumens on 18 watts, or 122 lumens/watt. That's about 40% savings based on specs.

But also this is kind of academic, since in reality you are replacing a 40 watt bulb with an 18 watt bulb, so the electrical savings is exactly that ratio. Watt cost per lumen is kind of an arbitrary figure compared to watt cost per tube in any tube replacement scenario.

And you can't even assume that the light level is lower. In reality the LED light is effectively brighter because of the directional nature, and while that won't create an additional savings in itself, in my case, using half the number of tubes definitely does.
I love it when a Plan B comes together!
Steve
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Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #16 on: April 27, 2022, 02:29:46 PM »
@Muzzerboy

In my view it's extremely simple (like me!)

I am replacing fluorescent tubes that consume 70 watts with LED replacements that consume 24 watts. So my electricity consumption will be 24/70 or 34% of what it was. 100% reduced by 34% is a 66% reduction.

As the LEDs are giving me subjectively slightly better illumination than I was getting before then the only down side is the capital cost. These particular units are guaranteed for 3 years.
Andrew Mawson
East Sussex

Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #17 on: April 27, 2022, 02:56:14 PM »
Once again, theory meets reality.
I love it when a Plan B comes together!
Steve
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Offline WeldingRod

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Re: Electricity getting very expensive in the Workshop
« Reply #18 on: April 27, 2022, 05:31:23 PM »
You definitely want to bypass the ballast!  Don't waste power making it hot!

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Offline chipenter

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Re: Electricity getting very expensive in the Workshop
« Reply #19 on: April 28, 2022, 01:44:15 AM »
I fitted Gu10 downlighters over my working area over four years ago , I have had one failure recently two of the LEDs fell of , replacement was 3.99 for four on offer , over the lathe and mill are 12 volt downlighters even older no problems so far , as they are at head height they don't burn my head .
Jeff

Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #20 on: May 01, 2022, 03:45:56 AM »
Yesterday I replaced the remaining 24 tubes in the main workshop - some amazingly inaccessible over various machines - in fact the four that span over the Beaver CNC lathe one needed to walk on top of the machine enclosure. To my great surprise the wife volunteered which probably a very good thing as she must weigh about half of what I do !



. . . only another 41 to go in various other outbuildings and workshops but in all likelihood I'll leave them as they are 'occasional use' only.
Andrew Mawson
East Sussex

Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #21 on: May 01, 2022, 11:38:18 AM »
Andrew how is the light level? Does it feel brighter in there now?
I love it when a Plan B comes together!
Steve
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Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #22 on: May 01, 2022, 12:16:42 PM »
Yes very much so Steve for several reasons I think:

A/ The LEDs are actually brighter

B/ Although most of the fluorescents were less than a couple of years old a significant few weren't

C/ The fluorescent tube were pretty grimy so not allowing all the light out

D/ I was greatly inhibited from turning on lights, putting up with a bit of gloom. But much less so now!

Andrew Mawson
East Sussex

Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #23 on: May 01, 2022, 01:30:53 PM »
Same here.  :thumbup:
I love it when a Plan B comes together!
Steve
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Offline Jo

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Re: Electricity getting very expensive in the Workshop
« Reply #24 on: May 01, 2022, 04:05:55 PM »
I keep thinking about replacing my fluorescent tubes with LEDS but they still provide a very useful low wattage workshop heater especially useful  at this time of the year when I have turned off the night storage heater out there.

I may have mentioned that I am the proud owner of a 4KW solar array which means that in spring/summer/autumn all power use in my workshop is "free"   :ddb: The painful bit is winter when the sun is not that strong so there is not a lot generated  :bang: but at that time of the year I need to heat the workshop so a few extra watts of funded warmth is not going to be sneezed at.


On a slightly different usage of the LED in the workshop: I have a couple of the smallest LED flood lights mounted on the end of a goose neck with a 6" tarpaulin clamp on the other end for securing them. Very handy for over illuminating areas when the need arises  :dremel:

Jo


So many engines to build and yet so little time.

Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #25 on: May 12, 2022, 03:14:04 PM »
As part of my 'Electricity Reduction Exercise' I wanted to fit an 'Owl' real time monitor to my incoming three phase supply. I'd bought the monitor on eBay some time ago and knew that it worked however it's sensing current transformers that clip round the cable were too small for this massive cable. These are 70 mm csa / 225 amp rated and about 16.5 mm o/d . The sensors that I had would only accept up to 11 mm o/d.

Well it turns out Owl do make a suitable sensor but they are far from common. As luck would have it, trawling eBay produced two used ones and one brand new one that arrived today.

I've fitted them after a bit of a struggle wrangling the cables to get sufficient separation to clip the devices on.

As part of the testing I wanted a decent three phase load, so I thought that I'd run the spindle motor on the Beaver CNC lathe. A nice steady 1000 rpm, no load on it and it was drawing 30 kW  :bugeye: Now the motor is rated at 26.5 kW so the remaining 3.5 kW must be the servo system, hydraulic pump etc.

Now OK it's a big beefy motor but with electricity at the price it now is that's practically 1 an hour just to spin the blooming motor  :bang:

. . . . . not going to be leaving that idling to warm up in the future  !
Andrew Mawson
East Sussex

Offline Pete49

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Re: Electricity getting very expensive in the Workshop
« Reply #26 on: May 12, 2022, 11:22:32 PM »
And we keep getting told that renewables make power cheaper. We need to get rid of subsidies on wind and solar to show the real cost to the people.
oops..........oh no.........blast now I need to redo it

Offline philf

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Re: Electricity getting very expensive in the Workshop
« Reply #27 on: May 13, 2022, 04:26:12 AM »
At the moment wind power is the biggest contributor at 12.95 GW, solar is 2.55 GW. Nuclear is 5.25 GW.

http://www.gridwatch.templar.co.uk/index.php
Phil Fern
Location: Marple, Cheshire

Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #28 on: May 13, 2022, 05:19:34 AM »
Well you wouldn't think I got the Maths prize at school all those years ago - that lathe motor calculation is out by a factor of ten!

30 kW at 29.48 pence per kwH is 30 x 29.49 / 100 = 8.847 per hour  :bugeye:

Dare I ever turn it on again !

(oddly this morning it's drawing 26.97 kw not 30   :scratch: )
Andrew Mawson
East Sussex

Offline WeldingRod

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Re: Electricity getting very expensive in the Workshop
« Reply #29 on: May 13, 2022, 10:26:01 AM »
That sounds really -wrong-.  A spindle motor drawing full power with no load???  It should be maybe 3kW!  If it is a three phase motor rather than a vfd you might be seeing reactive power rather than real power.  Or your spindle brake is on   A simple rectifier input VFD will have horrid harmonics that will totally flummox cheap power measurement chips...
If you've got an IR gun or camera you might look at the motor or cables.  30 kW going into any of that will make stuff hot PDQ!

Um, now that i think more, I bet your current transformer ratio is off by ten!

Do you have any dumb three phase heaters you could turn on?

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Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #30 on: May 13, 2022, 11:39:17 AM »
The motor is a DC Mawdsley one . It has a 1.5 HP cooling fan blowing into it all the time.

Current consumption of other devices seems sensible - certainly not out by a factor of ten
Andrew Mawson
East Sussex

Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #31 on: May 13, 2022, 11:41:15 AM »
26.97 KW = 36 Hp.  :jaw:

It can't really take that much to spin a ground shaft in precision bearings.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #32 on: May 13, 2022, 11:44:41 AM »
OK it's spinning the gear train as well but I agree to being surprised.

Does a DC motor actually vary it's consumption much? With AC drive you have the motor reactance which goes down on load hence drawing more amps - what is the case in a DC drive?



Andrew Mawson
East Sussex

Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #33 on: May 13, 2022, 11:51:03 AM »
Maybe Ebay purchases didn't pan out this time? Not that I don't make them myself......
I love it when a Plan B comes together!
Steve
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Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #34 on: May 13, 2022, 11:52:39 AM »
26.97 KW = 36 Hp.  :jaw:

It can't really take that much to spin a ground shaft in precision bearings.

It's rated at 26.5 HP 400 volts and  34 to 75 amps DC depending on speed with 170 volts on the field coils whose current is separately controlled  - plate below
Andrew Mawson
East Sussex

Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #35 on: May 13, 2022, 11:56:18 AM »
Maybe Ebay purchases didn't pan out this time? Not that I don't make them myself......

Not sure what you're referring to Steve - the Owl monitor (had it for years) and the new genuine Owl sensors and the used ones  check out 100% - after all they are only a few turns of copper wire and a split ferrite core in a plastic housing.

. . . may be you were referring to something else  :scratch:
Andrew Mawson
East Sussex

Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #36 on: May 13, 2022, 12:16:53 PM »
Andrew are they the appropriate senders for that monitor? Does the monitor have internal settings for different model senders/transducers? Do the two used transducers check out?

I have depth sounders that take same brand transducers. BUT, you have to go into settings to change to the model number transducer. I don't own an OWL, so I have no way of knowing, simply asking questions that occur.
I love it when a Plan B comes together!
Steve
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Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #37 on: May 13, 2022, 12:21:38 PM »
The transmitter unit takes in the coil connections from the three phases and Owl seem to only sell two varieties, examples of both of which I have. There is no setting up on the transmitter but as I  say the readings seem sensible with other loads.

I'll try it with the Kiln when I go over and feed the pigs in a minute
Andrew Mawson
East Sussex

Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #38 on: May 13, 2022, 12:23:51 PM »
Well, as was said earlier, all that power is eventually going into heat. You have a 27 killowatt heater running if somehow this power reading isn't wrong. So are you seeing 92,000 BTU/hr in the vicinity?
I love it when a Plan B comes together!
Steve
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Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #39 on: May 13, 2022, 01:03:31 PM »
Pigs fed and kiln power measured. It's rated or at least plated, at 13.5 kW three phase. From a base load of about 2kW the power used jumped up to 14.4 kW.

So I reckon the Owl monitor, though not calibrated to NPL standards, is giving a pretty fair indication of power used.

Now the machine drives the Mawdsley DC motor using a KDK DC drive with its associated blower cooling. Attached the to KDK drive is a Field Driver that I have actually added a fan to as it's output Thyristor used to run unacceptably hot. The main motor has as I previously mentioned it's own external cooling fan (750 watts NOT 1.5 kW as I had thought).

So energy as heat is being extracted all over the place and yes it does warm the workshop in a nice but expensive way!

I am as puzzled as others regarding the fact that the consumption is so high unloaded - the motor does not over heat by the way.

. . . I think the readings on the Owl monitor are roughly correct

I'll try and get some readings with the Beaver powered up and ready to rock but without the motor spinning - I suspect the various other elements gobble up quite a few electrons.

Andrew Mawson
East Sussex

Offline PekkaNF

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Re: Electricity getting very expensive in the Workshop
« Reply #40 on: May 13, 2022, 02:04:52 PM »
Power factor on measurement? Resistive loads are fairly easy to use for calibration. I am sure you have factored this in.

Offline hermetic

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Re: Electricity getting very expensive in the Workshop
« Reply #41 on: May 13, 2022, 03:18:38 PM »
Can you get a tong tester round the input phases and get a current reading for each phase?
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Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #42 on: May 13, 2022, 05:11:15 PM »
Probably Phil. I certainly used to have at least three Ferranti clamp amp metres - certainly still have one but may have given the others away over the years.

Andrew Mawson
East Sussex

Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #43 on: May 14, 2022, 05:07:49 AM »
Now this is getting REALLY curious - I don't quite understand what is happening.

Running the machine up to the point that the motor can be started under program control, but NOT running, the OWL is telling me it's drawing about 3kw which is not unexpected.

Starting the motor and running it at a steady 1000 rpm at the spindle (through a belt / gear train so not motor rpm) my Fluke clamp ammeter is showing approx 16, 17, and 18 amps on the three phase inputs to the machine.

Now the OWL is showing about 11 kw attributable to the Beaver lathe (other things drawing a few 100 watts)

Now under these circumstances the other day it was drawing 26 kw, and I'm not imagining it as I have the photographs !

So I don't  really understand what is going on  :scratch:
Andrew Mawson
East Sussex

Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #44 on: May 14, 2022, 08:05:13 AM »
What kind of functions does the Owl have -- Hold, or Peak?
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Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #45 on: May 14, 2022, 08:50:38 AM »
Looked at a manual... doesn't look like it shows peak.

But a change in the voltage setting could account for the difference betw 27 and 11 readings. What is/was the voltage set at?

Or......could be the Beaver.....
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Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #46 on: May 14, 2022, 09:19:00 AM »
Looked at a manual... doesn't look like it shows peak.

But a change in the voltage setting could account for the difference betw 27 and 11 readings. What is/was the voltage set at?

Or......could be the Beaver.....

Absolutely nothing was changed on the OWL settings, and anyway it shows sensible consumption when the 13.5 kW kiln is turned on so I don't think it's that Steve.

It make absolutely no logical sense to me at the moment. Even the 11 kW seems awfully high just spinning an unloaded motor.

One thing that DOES tally  up is the 16 /17 / 18 amps draw on the 415 volt three phase input to the Beaver equates to about 11 kW power again confirming that the OWL is telling the truth.

Incidentally, in the past I have checked the Fluke clamp meter against my trusty Avo 8 multimeter and they correspond exactly.

Andrew Mawson
East Sussex

Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #47 on: May 14, 2022, 09:39:19 AM »
Well as Pekka said, power factor?

No telling how the Owl factors that in. It isn't something it allows you to set. And just making one assumption for everything could yield wildly differing results. If it uses a dynamic estimation internally, maybe it senses whether an inductive load is connected vs rectifier (as also mentioned earlier by Welding Rod). Maybe it estimated a different power factor for the two measurement samples?

It's basically just a clip on ammeter with internal calculations to yield power/energy usage. How it handles power factor is unknown.

One other possibility, Andrew I came across -- someone on a forum said rotating the connectors solved one of his reading problems -- worth a try?

Actually, Andrew, your Fluke ammeter will allow you to estimate power factor -- and energy consumption without the convenience of the owl, of course. But where they disagree, I'd trust the old meter and your personal calculations.
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Offline awemawson

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Re: Electricity getting very expensive in the Workshop
« Reply #48 on: May 14, 2022, 10:40:08 AM »
But Steve the odd thing is that I set up EXACTLY the same measuring conditions on the two occasions.


. . . no change to the Owl or it's sensors and transmitter - they weren't even moved

. . . no change to the Beaver Lathe whatsoever - in each case it was turned on, passed over it's references in X & Z, then the motor started with an S1000 M03 command to spin clockwise at 1000 rpm

Yesterday 26 kW . . . today 11kW . . . . it makes no sense whatsoever :scratch:

(But today I WAS able to corroborate the 11kW using the clamp meter)
Andrew Mawson
East Sussex

Offline vtsteam

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Re: Electricity getting very expensive in the Workshop
« Reply #49 on: May 14, 2022, 11:07:11 AM »
Well, I wasn't thinking you changed anything --- that leaves something changed internally in the meter, or the Beaver drew more one day than the next.
I love it when a Plan B comes together!
Steve
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Offline Pete49

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Re: Electricity getting very expensive in the Workshop
« Reply #50 on: May 14, 2022, 10:51:42 PM »
At the moment wind power is the biggest contributor at 12.95 GW, solar is 2.55 GW. Nuclear is 5.25 GW.

http://www.gridwatch.templar.co.uk/index.php

I don't dispute that, it's the subsides need to be taken away to show the true cost of generation. It's the subsidies that increase the costs.
oops..........oh no.........blast now I need to redo it

Offline philf

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Re: Electricity getting very expensive in the Workshop
« Reply #51 on: May 15, 2022, 03:37:29 AM »
At the moment wind power is the biggest contributor at 12.95 GW, solar is 2.55 GW. Nuclear is 5.25 GW.

http://www.gridwatch.templar.co.uk/index.php

I don't dispute that, it's the subsides need to be taken away to show the true cost of generation. It's the subsidies that increase the costs.

Hi Pete,

I was only pointing out that it's oil & gas that has rocketed in price. As far as I'm aware wind and sunshine are still free!

I'm involved in a small scale hydro project and we're locked into a contract which sets the price of the electricity we generate far below the current (no pun intended) market price.

Cheers.

Phil.
Phil Fern
Location: Marple, Cheshire