Monitor turns off for approx 1 second when fridge starts?? Why??

[ElectroMaster]

Hi Guys,

I've got this really strange problem with my computer. The problem is when the fridge turns on (I can hear it) my dual monitors flick off for about 1 second then come back on. Sometimes is is only one left monitor.

Everything was worked great until I changed the monitor cables from standard DVI cables to DVI Passive extenders over Cat5 (**broken link removed**).

How could this be happening? Would the fridge be sending out any kind of interference through the mains power? The cat5 cable that is used is not shielded, would buying high quality cable that is shield prevent this problem?

Also, my computer setup is not exactly 'normal'. I like my office quite so I have my base (the box part of computer) setup in the garage, and the monitors, keyboard, mouse and speakers setup in the office. I run 10 meter cables between the two locations to connect them. There are 2 monitor cables and 1 usb cable.

Regards,
EM

 

[ronsimpson]

The fridge is reminding you its time to get beer.

The DVI is very well shielded. Probably double shielded.
The Cat5 is not. (at all)

 

[ElectroMaster]

Hi Ron,

I like that! Beer o'clock!

I have ordered a roll of SFTP Cat 6 cable to replace the unsheilded cat 5 that I currently have. I'm still left wondering why a fridge can cause this issue and not say, a microwave, washing machine, etc.

Regards,
EM

 

[Nigel Goodwin]

Fridges generate quite a 'surge', and can send spikes down the mains - do you have decent mains filtering on the computer?.

However, having the computer so far away sounds like a VERY poor idea.

 

[ericgibbs]

hi EM,
The fridge compressor motor starts in a loaded state, so the initial current is high, this could cause a 'big' EM spike [ pardon the pun].!

Starting Load Requirements
Determining the starting requirements can be a bit more complicated. Certain electrical devices require additional power and current when initially turned on. This is true for motors because the rotor of the motor and the shaft driven load (fan, pump, compressor, saw, etc.) is initially at a standstill. It requires more energy to accelerate these rotating parts to operating speed than it does to keep them rotating. Therefore, during the period of acceleration, the demand on the power supply is greater. To precisely evaluate the motor starting capability the detailed motor characteristics need to be known. However, a rule of thumb is usually sufficient. Most engine driven generators will start a motor with up to 1/5th the horsepower of the engine, if it is the first load connected. For example, a 2500 watt generator driven by a 5 horsepower engine will usually start up to a 1 horsepower motor. This assumes a common type of motor design with NEMA code G starting characteristics. This data can be found on the motor nameplate.

 

[ElectroMaster]

Fridges generate quite a 'surge', and can send spikes down the mains - do you have decent mains filtering on the computer?.

I had my only good mains surge protector being used with the monitors so I'll change it round and use it for the base.

The fridge compressor motor starts in a loaded state, so the initial current is high, this could cause a 'big' EM spike [ pardon the pun].!

LOL. That does make sense.

Thank you all for the comments, I'll wait 24 hours and see if my monitor turns on and off with the surge protector at that base

Regards,
EM

 

[ghostman11]

this is of no help at all but i get the same thing with one of my monitors, the one that is plugeged into the vga connector makes the screen go blank for a couple of seconds when i switch on my laser printer!! yet the HDMI monitor stays on,
i have no idea why but i guess i just kinda 'LIVE' with it!
as for the main box in a different room...............i am too lazy to walk to another room to put a cd in etc. plus in my office there is so much other noise going on i cant hear the pc if i put my ear up close to it

 

[ronsimpson]

If a monitor looses H or V sync it may blank the screen until it can PLL to the sync again. If it were not for blank on loss of sync you could see the picture roll and or tumble until the monitors locks to the signal.

DVI should have this problem more than VGA.

 

[ghostman11]

ooops sorry i had it the wrong way round!!! it is indeed the vga that stays on and hdmi that dosnt on mine!

 

[MrAl]

Hi,

Yes monitors have a build in auto detect to detect the signal/resolution and if they cant figure out what they are getting they will auto switch to "resolution not supported" but before they show that message they will blank the screen, and if the signal improves it may take a full second or more for them to decide it's ok to try to display the data coming in. Thus, noise somewhere in the signal can cause quite a problem.
There's also a chance it can come in over the power supply line to the monitor, but i think a problem there is less likely as the internal supply probably has adequate filtering. Never know for sure though until it's tested.

 

[Diver300]

Could it simply be the voltage dip caused by the fridge starting? Is the monitors rated at 230 V only, or is it rated 110 - 240 V. If it is rated to the wider voltage range, there would have to be a serious dip to cause it to blank.

 

[ElectroMaster]

The monitors are rated at 100-240v.

I tried placing the surge protector on the base of the computer but the monitors still have the problem. I am waiting for my new cat6 shielded cable to arrive to see if that helps.

 

[Reloadron]

If I had to guess on this my thinking would follow that of Diver300. I don't see the fridge starting as a surge but more as a dip in line voltage. The instant the compressor kicks on there has to be an immediate dip in line voltage. If the dip is great enough I could see the monitors behaving as they do. Has this been an ongoing as in always problem or did all work fine and then suddenly screw up?

Ron

 

[ElectroMaster]

The only thing I changed was the monitor cables. I've gone from 10M DVI cables to DVI Extenders (**broken link removed**) that use Cat 5 cable.

 

[mvs sarma]

Please try to have computer and monitor in another phase instead of same phase where the heavy inductive loads are wired.
also, it would be better if the heavy loads are wired separately from the mains cut out (entry)point by individual cables against in the common wiring system.
Alternative, the computer can have its input from the mains entry point.
and if space is there place one 4.7uF 275V oil capacitor at the mains between neutral and live, used by the computer. Temporarily for test purpose, you may try out computer close to mains entry .
Hope this should sort out.

 

[BrownOut]

place one 4.7uF 275V oil capacitor at the mains between neutral and live, used by the computer.

Seriously, don't do that.

 

[mvs sarma]

these are called Power factor and spike suppression, Nothing serious about these.
Any inductive loads, we are asked to provide power factor correction .

 

[BrownOut]

Household appliances don't require power factor correction. Instead I would suggest one use a power strip with surge suppression. These are engineered for this purpose.

 

[tvtech]

these are called Power factor and spike suppression, Nothing serious about these.
Any inductive loads, we are asked to provide power factor correction .

Learning here and all. Nice site to be a member of.
BrownOut knows stuff I still have to learn too.

Cheers
TV TECH

 

[ElectroMaster]

I received my new Cat6 cable (Shielded FTP) today and wired up one monitor. To my dismay it works worse than that un-shielded Cat5 cable.

What happens with the cat6 is the screen is blank and a message appears stating

The current timing is not supported by the monitor display.
Please change your input timing to 1920x1080@60hz

The computer is setup fine, its the hardware (cable/dvi extender) that is causing this..

Back to the drawing board!