Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

In our home, there is a mechanic who often uses a welding plant. When he uses it, I think we get a power surge. My UPS ticks madly (not beep, it ticks). Sometimes, I even lose power to the keyboard. When typing, some keys get missing.

  1. My question is, is it good for the computer? The UPS claimed to have surge protection. But isn't it working? What should I do to protect my PC?

  2. The second question is, I also have a broadband router which is not connected to the UPS. Will it be effected?

I just noticed that I'm using a Belkin surge protector. Isn't that enough?

share|improve this question
up vote 3 down vote accepted
  1. No, if your keyboard operation is being interfered with, there must be some possibility of other unwanted effects.

  2. It must be possible.

The problem could arise form either spikes or sags in the power-supply or through direct electromagnetic interference (think radio waves, early morse radio transmitters used spark-gaps, I believe arc-welders also have an electrical current sparking across an air gap when the welder strikes the arc)

Could you ask the welder to check his earthing

If electromagnetic disturbances are detected then it shall be the responsibility of the user of the welding equipment to resolve the situation. In some cases this remedial action may be as simple as earthing the welding circuit

share|improve this answer

There are different types of UPS systems. One type normally feeds power to the computer directly from the mains, but "cuts over" when power is lost. The other major type converts all power from AC to DC, then back to AC, so that you are, in effect, always running off the UPS.

This second type is more expensive and less efficient (and will put out more heat), but is what you need if your power source is constantly changing. The first type is intended more to just handle simple power failures.

It sounds like you have the first type. Probably the clicking you hear is the unit cutting over and cutting back.

Re the router, low-power devices like that are naturally more immune to power problems. Ideally it should be on your UPS along with your computer, but if not that then a good quality surge protector should be used.

(Note that the effects you're seeing are probably not due to RF interference ("electromagnetic disturbances") but rather power line transients, because the welder draws more current than you're home's power lines can readily supply.)

share|improve this answer
I just noticed that Im using a belkin surge protector ( Isn't that enough? – THpubs Nov 2 '12 at 12:17
@EApubs: A surge protector cannot "fill in" a drop in voltage caused by an arc-welder drawing excess current. You probably need a good high-capacity on-line UPS for that. – RedGrittyBrick Nov 2 '12 at 14:27

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .