Electrical Engineering - UPS to fix dimming lights due to laser printer?

Author

UPS to fix dimming lights due to laser printer?

kevincw01

2007-02-19, 3:25 am

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
rhythmically 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). The hair
dryer in the bathroom does the same thing but it only affects the
bathroom lights while the printer seems to affect the whole house.

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: http://www.dell.com/downloads/globa...iron/1815dn.pdf

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 in another 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.

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?
Like I said, the spec sheet says peak is 450 watts which lasts for the
length of the printing(usually 10 seconds). But, on the back of the
unit, it lists 5.4amps which yields about 650 watts(according to my
calculations). My guess is that a 1000VA UPS will do the trick.

Thanks for your help/suggestions/pointers
-Kevin

Ken

2007-02-19, 9:25 am

kevincw01 wrote:
> 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
> rhythmically 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). The hair
> dryer in the bathroom does the same thing but it only affects the
> bathroom lights while the printer seems to affect the whole house.
>
> 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: http://www.dell.com/downloads/globa...iron/1815dn.pdf
>
> 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 in another 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.
>
> 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?
> Like I said, the spec sheet says peak is 450 watts which lasts for the
> length of the printing(usually 10 seconds). But, on the back of the
> unit, it lists 5.4amps which yields about 650 watts(according to my
> calculations). My guess is that a 1000VA UPS will do the trick.
>
> Thanks for your help/suggestions/pointers
> -Kevin
>

I think you would be better off fixing the problem. All electrical
devices consume some power, therefore adding a UPS will provide a source
of power when the input is lost or drops too low, but in being on will
make your situation worse. That is because MORE current will be
consumed than that of just the printer.

If lights are dimming when this device is running, there is a voltage
drop that is occurring on the AC lines. Most often this is due to a
high resistance path in your electrical wiring. Poor connections, too
small gauge wire, and possibly limited AC input service (although this
is probably the least likely) could be responsible. You should get
someone qualified such as an electrician to take some measurements.

For what it is worth, aluminum wiring is famous for this type of problem.

Ben Miller

2007-02-19, 1:25 pm

"Ken" <user@domain.invalid> wrote in message
news:ashCh.94694$2m6.29869@bgtnsc05-news.ops.worldnet.att.net...
> If lights are dimming when this device is running, there is a voltage drop
> that is occurring on the AC lines. Most often this is due to a high
> resistance path in your electrical wiring. Poor connections, too small
> gauge wire, and possibly limited AC input service (although this is
> probably the least likely) could be responsible. You should get someone
> qualified such as an electrician to take some measurements.
>
> For what it is worth, aluminum wiring is famous for this type of problem.

DImming lights don't always mean there is a problem with the wiring,
althought they could. Given that the only other problem is the hair drier,
It is more likely that the dimming is just due to normal voltage drop. It
only takes a few volts to cause noticeable flicker, which could be well
within the acceptable voltage range. A laser printer pulls high current
peaks which cause this. Every recommendation you will find calls for a
dedicated circuit for the LP, which would minimize this problem. I agree,
however, that having someone inspect it is the only way to know for sure.

Ben Miller

--
Benjamin D. Miller, PE
B. MILLER ENGINEERING
www.bmillerengineering.com

Beachcomber

2007-02-19, 5:25 pm

>DImming lights don't always mean there is a problem with the wiring,
>althought they could. Given that the only other problem is the hair drier,
>It is more likely that the dimming is just due to normal voltage drop. It
>only takes a few volts to cause noticeable flicker, which could be well
>within the acceptable voltage range. A laser printer pulls high current
>peaks which cause this. Every recommendation you will find calls for a
>dedicated circuit for the LP, which would minimize this problem. I agree,
>however, that having someone inspect it is the only way to know for sure.
>

There are subtle factors about wiring that may contribute to your
"dimming lights" problem.

1. Loose connections - age, sloppy orginal work, whatever... may have
an effect on voltage drop in the outlets themselves. Carefully turn
off the power at the main breaker/fuse box and make sure all of the
wire connecting screws on the outlets are tight. Splices with wire
nuts must also be tight.

2. Most likely cause - overloaded circuits - or circuits near
capacity. It is not difficult to overload a 15 amp circuit. The
more active appliances and lights on the line, the greater the voltage
drop. Thus when your printer calls for 450 watts of additional power,
the voltage is going to drop on the whole circuit, causing the lights
to dim.

20A circuits are better than 15 amp circuits (because if they were
installed correctly, the wire is larger and can handle more
current)... thus... less voltage drop for a given load. Of course,
you may only have 20A circuits wired for you kitchen appliances (or
not at all, if your house is really old). Bottom line, if you
can... move your printer to a 20A circuit or install a 20A circuit for
the printer.

3. Long circuits - The longer the distance your outlet is from your
breaker/fuse box, the greater will be the voltage drop. If you have
any control over this, try to keep this distance as short as possible.

4. Under capacity service entrance/fuse box. You say the dimming
problems happens on multiple outlets throughout the house. Are they,
in fact, on different circuits? If so, your service entrance/fuse
box may be under-capacity. In the 1950's... 60A was common for
apartments and old houses. 100A for newer houses.

In the year 2007, that is no longer enough for most houses, because
many things used today (dishwashers, air-conditioners, computers,
laser printers, central vacuums, etc.) weren't all that commonplace
during the 1950's. 200 Amp is the minimum, in most cases.

Upgrading the service/fuse box to your house is the most expensive
fix. It may also involve running new circuits and wiring to your
appliances.

Beachcomber

Long Ranger

2007-02-20, 8:25 pm

You've most likely got problems with your wiring. A high resistance joint
is not only annoying, but also can be a real fire hazard. A very slight
flicker can happen, but a noticeable sag of any duration is not acceptable.
I recently had that problem and I actually had to have the utlity company
over twice before they took care of a burnt splice out on the pole. If that
splice had been inside, it likely would have lit the house up. It was
actually burnt, not just warmed. One thing you might try is getting a chunk
of romex and hooking it directly into your panel and bring it inside like an
extension cord and run that machine on it as a test. If it doesn't sag the
rest of the house hooked like that, then you need to look through the
circuit it was on, and probably the whole house. If it still sags, it's
somewhere farther up the line, maybe the utlity companie's conductors, or
the meter socket etc.

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