multi-function printer dimming lights

[NetKev]

I got a multi-function laser printer for my home office. It replaced an old laser printer that I had. This new printer causes the lights to dim in the whole house when I print. While it prints, the lights rhythmicly dim. This stops once the printer goes to sleep. My old printer never did that. I ended up buying a new laser printer (for unrelated reasons) and it does the same thing(if not worse).

I tried plugging it into different outlets without a difference. This latest printer(Dell 1815dn) pulls 450 watts while printing. Here's the spec sheet if you're interested:

Anyways, this bugs the heck out of me and my wife. Especially when my wife prints out large pdfs while I'm reading :) I read about this phenomenon on the group and know that it's common...

This house we're renting was built in the 1950s and so I'm sure it doesn't have the greatest electrical service.

But my question is how to fix it. Since we're renting I don't want to make any drastic electrical system changes(cant actually). I was thinking a UPS would work or maybe a power conditioner since I'm assuming that the draw from the printing is so high that the rest of the appliances are being starved. If a UPS were in the mix to provide this extra power then the rest of the appliances wouldn't have a problem.

If my solution theory is correct, any idea what size UPS I will need? I'm hoping I don't have to spend a lot of money for it but who knows.

Thanks for your help/suggestions/pointers

-Kevin

[Tony Hwang]

Hi, Does your light dim when your fridge kicks in or you use mirowave oven, etc.? UPS = uninterrupted power supply, what makes you think UPS is helpful? Maybe your place's wiring is at the borderline approaching max capacity and that extra load printer is it. Laser printer has fuser(heater which draws some current when printing).

[NetKev]

Hi, no my fridge and microwave don't cause the lights to dim. In the bathroom, the hair dryer does cause the lights to dim but only in that room.

My rational for the UPS solution was that since the printer runs at

450 watts when printing, then, say a 600 watt (1000VA) UPS battery would act as a buffer during the high load times. Doesn't this make sense?

[Tony Hwang]

Hi, It may help since it is on float charging battery situation. I'd try the printer in several different outlet to really isolate it. Plug it in and print a test page or sosmething.

[Dave Martindale]

No. The printer likely does not draw enough current to drop the voltage low enough for the UPS to switch to battery operation. So the UPS will do precisely nothing, but the load will still cause your lights to dim slightly. The printer probably works fine down to 95 V or so, while your lights will visibly change in brightness with only a few percent change in line voltage.

There are UPSes that provide line voltage regulation via a multi-tap transformer. But they only adjust voltage for the device downstream. The lights are upstream of the UPS, so they'll see as much voltage change as ever.

The right way to fix your problem is to run a new circuit for the printer, one that doesn't share wiring with any lights.

A simpler fix: print large documents just before going to bed.

Dave

[terry]

Something weird. A hair dryer or electric kettle or a toaster each take more than twice that 450 watt rating. A UPS without finding out the real cause sounds like an expensive solution, possibly bypassing finding the real cause of a potentially dangerous situation?

[kevincw01]

OK, fair enough. What about a power condition that does "AC Regeneration", or is this the same as line voltage regulation you spoke of.

[Joseph Meehan]

Laser printers do draw a lot of current when starting up. They vary and some do a lot more than others. I have two laser printers and if I put either of them on the same circuit as my UPS they trigger it. However I have several circuits in the area so they each are one a separate line and the UPS-computer are on a third line. No problems. One printer will slightly dim my overhead light and the other one dims the hall light outside my library. Works for me.

Note: running 12 gauge wire rather than the 14 gauge that was there would likely reduce the effect, but it does not bother me so I never bothered.

[w_tom]

UPS will only cure symptoms. Worse, many UPSes in battery backup mode output electricity so 'dirty' as to harm some small electric motors - such as those inside a laser printer.

Those lights are dimming because wires have loose connections. The fact that some appliances cause dimming and other don't helps to locate a connection failure. Age of wires make no difference. Either connection of wires is completely good OR that connection is bad and causing dimming.

If wires enter wall receptacles in rear, then that could be reason for defective connections. Simply remove cover plate to look inside. Wire must be fully wrapped around screw on side of receptacle.

Not only might some lights dim. Other lights may brighten. Which do and don't? Well, basic facts such as what outlets share common circuits, which on same side (phase) and different side of AC electric mains box, etc - these facts will be necessary to answer your question.

A UPS is a fool's solution - a classic example of curing symptoms. The dimming could, remotely, be an indication of a human safety problem. Why then would you cure symptoms? Find and fix the problem.

[Dave Martindale]

That's probably referring to an "on line" UPS, which continuously converts AC to DC, then back to AC using an inverter. This is larger and more expensive (because the electronics have to run all the time, not just when there's a power failure) but it still won't solve your problem.

With an on-line UPS, the circuitry is designed to never discharge the battery when AC power is available. So when your printer's fuser turns on, it draws 400 W or so extra from the UPS, which will in turn draw

*more* than 400 W extra from the AC line. So it will have even more effect on your lights.

The only way to prevent a UPS from affecting house voltage at all is to unplug the UPS just before you start printing, so it doesn't draw any power from the house and the batteries supply all the power. However, you'll need a *big* UPS for this. It needs to be able to supply the startup surge of the fuser, not just its steady-state running power.

Also note that most UPSes will operate for only 5 minutes or so fully loaded - if you want to print long documents, you'll need one with more battery capacity. When the batteries have been discharged, it takes many hours for them to recharge, so you can't print very often. And, finally, doing this very often will shorten the life of the batteries.

Dave

[Tony Hwang]

Hi, UPS comes in many shapes and forms. Battery, CVT, Invertor, Electronic regulator, etc.

[Art]

Most UPS's warn against connection to a laser printer. The new laser printer sucks up more power than the old so it can warm up faster and get the first page out faster. That was true of my Xerox, Brother, and Minolta laser printers. All dimmed the lights. Interestingly, my 1 year old Epson color laser multifunction machine (yes it is color and laser) does not cause the same dimming.

[Art Todesco]

[w_tom]

Author is not talking about a $500 or $1000+ UPS to address light dimming from a laser printer. Other plug-in 'solutions' that might be implemented are even more expensive. Still that UPS would only cure a symptom. Symptom that may also be related to a potential human safety problem. Fix the problem. It's cheaper. It's safer. A UPS will not solve the problem. At best, a UPS can only cure symptoms. Laser printer must not cause oscillating light dimming. More symptoms of a correctable wiring problem - more likely a simple and inexpensive solution - a loose wire connection.

Most UPSes are less than $200 types. Computer grade UPSes that can even contribute to damage of small electric motors - and again are no solution to a wiring problem. Even a voltage regulator will cause increase current - even worse light dimming. Still does not solve the problem.

Any discussion of a plug-in solution should have been terminated up front. Wiring problem is probably a loose connection. Fix the problem; do not cure symptoms.

[Dave Martindale]

Properly-functioning aluminum wiring should not have any effect. Aluminum is less conductive than copper for equal cross-section area, so the electrical code required use of aluminum 2 gauges larger than the copper that would be used for the same load. This makes the resistance per unit length about the same for the two wire types, and you *shouldn't* see any worse dimming with aluminum.

On the other hand, aluminum is notorious for connections increasing resistance over time, so this may be an indication that you have an aluminum wire connection that is degrading. Excessive dimming is a sign that something is wrong, not a normal side effect of aluminum wire.

Dave