Laser printer draws current in a spike, what for?

In alt.engineering.electrical snipped-for-privacy@ipal.net wrote: | In alt.engineering.electrical Andrew Gabriel wrote: | | | In article , | | John Woodgate 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 ;-) | | 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.

Huh? How about electric clothes dryers? And our 240VAC is actually

Where I am there are two houses to a transformer (200A service typical).

...Jim Thompson

Tssk @ you John.

You're suggesting that the IEC has 'versions' of the ENs ? Other way surely !

Graham

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.

In alt.engineering.electrical Jim Thompson wrote: | On 30 Aug 2004 19:29:10 GMT, snipped-for-privacy@ipal.net wrote: | |>In alt.engineering.electrical Andrew Gabriel wrote: |>

|>| In article , |>| John Woodgate 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 ;-) |>

|>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. | | Huh? How about electric clothes dryers? And our 240VAC is actually | 120-0-120 so the cord is never more than 120V relative to ground.

Sorry, I accidentally omitted that it applies to loads under 1440 watts. Above that, most loads need a dedicated circuit, anyway. Personally, I would prefer lowing the 1440 watt figure of 210.6(A)(2) or even getting rid of that limit (or setting it at 300 volts).

In a house I'll be building in a few years, I'm going to see if I can get away with putting in lots of 6-20R's for 240 volts in many places. Hopefully 210.6(A)(2) won't be interpreted to get in the way of that. I will have a couple over-1440 watt appliances, so hopefully it will be OK.

| Where I am there are two houses to a transformer (200A service | typical).

I've seen much variation. My grandfather had 3 transformers to himself. But he had three phase.

One house I used to live in had 1 transformer to itself because it was an add-on to a development that wasn't originally planned. I've also seen as many as 12 houses run from 1 transformer and it wasn't very big, either (looked to be 75 to 100 kVA at most). But if those houses had

| 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".

In alt.engineering.electrical Andrew Gabriel wrote: | In article , | snipped-for-privacy@barrow.com (Floyd L. Davidson) writes: |> snipped-for-privacy@cucumber.demon.co.uk (Andrew Gabriel) wrote: |>>In article , |>> John Woodgate 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.

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.

The most I know of is my father's summer cottage, where there were 13 cottages on a single transformer (I say were because one winter the top of the pole the transformer was on broke off and energized the secondary with

I read in sci.electronics.design that snipped-for-privacy@ipal.net wrote (in ) about 'Laser printer draws current in a spike, what for?', on Tue, 31 Aug 2004:

Experience shows that there is a huge allowance that can be made for diversity. The average consumption of a UK house is 1 kW. I believe it's

My monthly average for July was 8.1kW, so I probably had peaks 2X-3X as much.

...Jim Thompson

If you reread 210.6(A) and observe the puncuation you'll see that it refers to rooms of

Check with your AHJ, but most localaties will enforce the article with that understanding.

True, but I have encountered apartment, and other communal structures with a

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--

I read in sci.electronics.design that Jim Thompson wrote (in ) about 'Laser printer draws current in a spike, what for?', on Tue, 31 Aug 2004:

Mostly for egg-nishners?

| If you reread 210.6(A) and observe the puncuation you'll see that it refers | to rooms of | | 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:

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 ...

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

| 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.

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

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

I don't get your point. Our (US) 240 volt circuits are

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.

| 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

| 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.

In alt.engineering.electrical snipped-for-privacy@bellatlantic.net wrote: | snipped-for-privacy@ipal.net wrote: | |>In alt.engineering.electrical Andrew Gabriel wrote: |>

|>| In article , |>| John Woodgate 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 ;-) |>

|>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.