Laser printer draws current in a spike, what for?

In alt.engineering.electrical snipped-for-privacy@ipal.net wrote:
wrote: |
| |> According to US sources, problems such as you report never occur, and
| |> they don't need to implement the IEC versions of those ENs as US | |> standards. So you are actually just imagining the flicker. (;-) | | | | The irony is this is quite common in the US, but I've never seen | | it happening in a 240V country ;-) | | We do have 240 volts. The problem is that we also have the NFPA that | publishes the NEC which in 210.6(A)(2) restricts the voltage for cord | and plug equipment to a maximum of 120 volts relative to ground, thus | disallowing the use of the 240 volt connection for the typical laser | printer. Of course one might get around this if they say it is a 26A | load instead of a 8A (relative to 120 volts).
While editing and re-editing, the "1440 watt" specified in 210.6(A)(2) got dropped from my post and I intended to mention it.
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writes:

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> | Phil Howard KA9WGN |

210.6(A) applies to dwelling and guest rooms of hotels, motels, etc. This
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wrote:
| 210.6(A) applies to dwelling and guest rooms of hotels, motels, etc. This | article wouldn't be applicable to homes, and office environments. It also | relates to voltage between conductors. Ground isn't referenced in 210.6(A). | | 210.6(A)(2) restricts to 1,440 va and below, or 12 amps at 120 volts again | in dwelling and guest rooms of hotels, motels, etc.
Homes are considered dwellings.
| Most 240 volt circuits, in areas of the USA that I'm familiar with, are 120 | volts with respect to ground with the exception of the wild leg of a 240 | volt 3 phase delta, with one leg center tapped to ground. In that case the | wild leg usually isn't present in panels designed for single phase loads.
And most of the homes don't have the wild leg at all.
But some places have 208Y/120, so no 240 at all, but it is 208.
| Never enough time or money to do it right the first time, but always enough | after the fact! :-]
It's called "wait for a disaster to happen".
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wrote:

This
also
210.6(A).
again
If you reread 210.6(A) and observe the puncuation you'll see that it refers to <dwelling AND guest> rooms of <hotels,motels, etc.>
Check with your AHJ, but most localaties will enforce the article with that understanding.

120
the
loads.
True, but I have encountered apartment, and other communal structures with a 240 Delta one leg center tapped, service. Usually the wild leg will only be present in panels for common area supporting equipment such as HVAC, pump, and other large current drawing equipment.

enough
With the atten you are paying to dietail I would enjoy seeing your final electrical plans for your impending home. I suspect I would enjoy living in it!
Louis-- ********************************************* Remove the two fish in address to respond

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wrote:
| If you reread 210.6(A) and observe the puncuation you'll see that it refers | to <dwelling AND guest> rooms of <hotels,motels, etc.> | | Check with your AHJ, but most localaties will enforce the article with that | understanding.
The punctuation to construct that logic is not there. There is also a switch between "and" and "or" which implies a separate context. Thus you have (my addition of parenthesis):
In (dwelling units) and ((guest rooms or guest suites) of hotels, motels, and similar occupancies), the voltage shall not exceed 120 volts nominal, between conductors that supply the terminals of the following ...
I'd like to have your interpretation. But such an intent would not be written as it has been. Instead, that would be written like:
<example not real NEC> In dwelling units, guest rooms, or guest suites of hotels, motels, and and similar occupancies, the voltage shall not exceed 120 volts nominal, between conductors that supply the terminals of the following ... </example not real NEC>
So if the intent was to narrow "dwelling units" to just those of hotels, motels, and similar occupancies, it would be appropriately written as in my example.
Still, I think I can get away with having extra 240 volt receptacles around by merely having (or saying I will have) a portable appliance that uses 1500 watts or more. A sealed oil heater I used to have in fact had switchable 600 and 900 watt element and could run both at the same time. But that ran on 120 volts. I only need to find me a 240 volt version (or hope they designed it with reconfigurable dual elements for world markets).
| True, but I have encountered apartment, and other communal structures with a | 240 Delta one leg center tapped, service. Usually the wild leg will only be | present in panels for common area supporting equipment such as HVAC, pump, | and other large current drawing equipment.
Still, all the single phase loads are running off one of the phases.
And utilities are phasing out delta apparently due to problems with it such as blowing fuses on feedback due to a single phase outage. Now that could still be done with a Scott-T setup without the delta feedback problem.
| With the atten you are paying to dietail I would enjoy seeing your final | electrical plans for your impending home. I suspect I would enjoy living in | it!
Split level A-frame with beam construction and almost all solid wood paneling walls and solid wood floors at 45 degree angles. Each bedroom has its own bath and a balcony.
I am working on a program to convert a text-like construction language into floor plan graphics and will be designing it that way, eventually.
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wrote:

refers
that
I suspect that you have software programming experience? It appears that you are taking a Bolean approach to the text?
There is also a switch

(my
motels,
nominal,
written
I believe you've identified the problem! It's your phrase "appropriately written". At best the NEC is a convoluted exercise enough to render the possibility of much of it being unmistakeibly clearly written as to avoid misunderstandings very unlikely. :-]
Every AHJ I've experienced considers 210.6(A) to solely apply to transient forms of accomodation, and not private residential/apartment housing. If incorrect there are numerous small air conditioners, and other small appliances in homes that are in danger of non-compliance. :-]
Rather than take my, or anyone elses word on the subject consult your local AHJ. Most AHJ will be very accomodating, and helpful when it's clear your interested in an opinion to assist you in being in compliance with national, and local codes.
Louis********************************************* Remove the two fish in address to respond

with a

be
pump,
in
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wrote:
| I suspect that you have software programming experience? It appears that you | are taking a Bolean approach to the text?
Only to analyze, not to interpret. Interpretation is being made by proper grammatical usage. I double check that by reversing the process and determining how to say various possible intentions and seeing what matches up.
| I believe you've identified the problem! It's your phrase "appropriately | written". At best the NEC is a convoluted exercise enough to render the | possibility of much of it being unmistakeibly clearly written as to avoid | misunderstandings very unlikely. :-]
And to the extent that is true (and it very well may be, given many other examples), that means no intrepretation is reliable.
| Every AHJ I've experienced considers 210.6(A) to solely apply to transient | forms of accomodation, and not private residential/apartment housing. If | incorrect there are numerous small air conditioners, and other small | appliances in homes that are in danger of non-compliance. :-]
I've not seen a small air conditioner that violates it. Everything below 1440 watts is 120 volts.
| Rather than take my, or anyone elses word on the subject consult your local | AHJ. Most AHJ will be very accomodating, and helpful when it's clear your | interested in an opinion to assist you in being in compliance with national, | and local codes.
What I need is something broader than one one AHJ will interpret it as.
I'd love to see it interpreted as the transient dwelling meaning. But if some AHJ didn't interpret it that way, I find no method to argue that such an interpretation is wrong.
Well, either way, that rules out a hotel in the US providing world voltage compatibility outlets for their foreign guests. Gotta use those step-up transformers.
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snipped-for-privacy@ipal.net wrote:

I don't get your point. Our (US) 240 volt circuits are 120 volts relative to ground. I've got a 240 volt cord and plug connected air conditioner. NFPA does not prohibit 240 volt appliances, so I'm missing your point.
In any event, you don't need a 240 volt circuit to solve the problem of dimming lights when the laser printer fuser heats. Put the printer on a separate circuit. Essentially, that is what putting it on a 240 volt circuit would do anyway, so the fact that it draws less current on 240 wouldn't matter.
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In alt.engineering.electrical snipped-for-privacy@bellatlantic.net wrote: | snipped-for-privacy@ipal.net wrote: |
wrote: |>
|>|> According to US sources, problems such as you report never occur, and |>|> they don't need to implement the IEC versions of those ENs as US |>|> standards. So you are actually just imagining the flicker. (;-) |>| |>| The irony is this is quite common in the US, but I've never seen |>| it happening in a 240V country ;-) |> |>We do have 240 volts. The problem is that we also have the NFPA that |>publishes the NEC which in 210.6(A)(2) restricts the voltage for cord |>and plug equipment to a maximum of 120 volts relative to ground, thus |>disallowing the use of the 240 volt connection for the typical laser |>printer. |> | I don't get your point. Our (US) 240 volt circuits are | 120 volts relative to ground. I've got a 240 volt | cord and plug connected air conditioner. NFPA | does not prohibit 240 volt appliances, so I'm | missing your point.
I intended to also include the 1440 watt limit from the code. Loads over 1440 watts can be supplied with 240 volts, no problem.
| In any event, you don't need a 240 volt circuit | to solve the problem of dimming lights when the | laser printer fuser heats. Put the printer on a | separate circuit. Essentially, that is what putting | it on a 240 volt circuit would do anyway, so | the fact that it draws less current on 240 wouldn't | matter.
It would help some. The voltage drop in the wiring up to the point where the circuits diverge, and the transformer impedance, will be there to some degree, but the lower current of a 240 volt connection will reduce it. OTOH, having it on the other phase of 120 apart from the lights will avoid it.
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snipped-for-privacy@cucumber.demon.co.uk (Andrew Gabriel) wrote:

Well... obviously the current is halved, but...
A laser printer that dims the lights???? Jus how common is that, really?
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FloydL. Davidson <http://web.newsguy.com/floyd_davidson
Ukpeagvik (Barrow, Alaska) snipped-for-privacy@barrow.com
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On Mon, 30 Aug 2004 12:03:06 -0800, the renowned snipped-for-privacy@barrow.com (Floyd L. Davidson) wrote:

I've seen it (NEC Silentwriter LC890). It's just a flicker- the problem is that the flicker is repetitive with the control of the fusion roller temperature and continued as long as the printer was switched on. My modern HP doesn't appear to do anything like that.
Best regards, Spehro Pefhany
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wrote:

I wonder how often 4 or 5 printers on one circuit might cause the fuse to pop, if "idle".
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     snipped-for-privacy@barrow.com (Floyd L. Davidson) writes:

And the percentage voltage drop is quartered...

Also, we don't run fixed lighting from same circuits as power outlets.
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| snipped-for-privacy@barrow.com (Floyd L. Davidson) writes:
|>>> According to US sources, problems such as you report never occur, and |>>> they don't need to implement the IEC versions of those ENs as US |>>> standards. So you are actually just imagining the flicker. (;-) |>> |>>The irony is this is quite common in the US, but I've never seen |>>it happening in a 240V country ;-) |> |> Well... obviously the current is halved, but... | | And the percentage voltage drop is quartered... | |> A laser printer that dims the lights???? Jus how common is |> that, really? | | Also, we don't run fixed lighting from same circuits as power | outlets.
Now days, most homes here have lighting split from outlets. I have to remember way way back to where they were shared.
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John Woodgate wrote:

Tssk @ you John.
You're suggesting that the IEC has 'versions' of the ENs ? Other way surely !
Graham
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I read in sci.electronics.design that Pooh Bear <rabbitsfriendsandrelati
printer draws current in a spike, what for?', on Tue, 31 Aug 2004:

Well, I don't think that 'version' is all that misleading. And in fact the standards process is becoming more and more interactive. A lot of CISPR 22 and 24 originated in CENELEC.
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What you're seeing, is the cycling of the heater for the fusing roller. This roller melts the toner into the paper. Without it, your print would simply blow away. It's integral to the operation of the printer.. Just don't put it behind your ups. There's really no need anyway, if the power goes out, then just restart the print later.
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X-No-Archive: Yes

hahahahahahahaha
me three. Mine's a BROTHER too. Brother DCP-1200 Scanner/Printer combo and it's not that old. Perhaps Brother's got an issue with their heater drive algorithm. It's ok if it's held on and caused a flicker every once in a while.
To the people who pointed out it's the heating element, I'm aware what the power is used for. My question was what the logical reason is for pulling current in the pattern my printer does.
I don't plug my laser printer into my UPS and only stupid users plugs one into an under the desk sized UPS. What I'm saying is Irise(dI/dT) is extremely fast. This in turn causes a line drop at high dV/dT. My UPS, which is on the same branch circuit transfers to battery every time the printer pulls a surge current.
UPS circuit transfers to battery in prediction of upcoming serious power problem not because the voltage drops too much, but rate of change of voltage (dV/dT) is excessive. When the cause of transfer information is extracted from UPS, it reports as "R", which means unacceptable rate of voltage change on APC UPS.
What did I do? I put the UPS on a different branch circuit with an extension cable and changed the ballast in light fixture to one equipped with an active PFC.
You might ask why active PFC ballast. The power factor controller IC is actively monitoring AC phase and DC bus voltage and it creates a near unity power factor as well as maintain a steady voltage on the DC bus. The controller samples the AC many times a cycle(In hundreds of KHz range) which is a must to correct power factor. The controller compensates for voltage dip and drives the MOSFET accordingly to maintain a steady DC bus voltage. Steady DC bus ensures flicker free lamp operation.
For us home users, "just put the printer on a dedicated circuit" isn't really an option.
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Might be interesting if you told us what Brand/model printer you are complaining about.
Was a know fact in early laser printers.
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That is also a problem with tv sets. When the power first comes on the cold filimants draw a large surge. What you can do is soldeir a surgistor in line with the device that heats the drum. When you turn it on at first the surgistor has a high impedance and as it warms up it resistance drops to a low value. This reduces or eliminates the inrush current (Also some times seen on large transformers) There are also surgistors that have built in points that close when the device heats up so there is no voltage across the device. When the power shuts off, the points open up to be ready for the next surge.
If you have an oscilliscope, I am assuming you would know how to do this.

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