PPP Input Voltage to high (up to 135V). What to do?
  • Hi, I am using a PPP in Mexico (a 120V US model). The input voltage in my house goes from 128 to around 135V). The PPP is shutting itself off now and then, perhaps to protect itself. Of course, this is very annoying. Is there a way to prevent this? Perhaps adjusting something on the PPP that would make the input voltage more palatable for itself? Does it make sense to put a voltage regulator in front of the PPP? In that case, what kind of regulator, rating, etc.?

    BTW, I have contacted the power company and they say it is "normal", that the voltage is within their operating tolerances :-(

  • The shutdown seems to be because of the voltage, as you say, although it also happens when the input voltage reading is around 130v, not necassarily 135v. perhaps there is a transient rise to 135V? When the input voltage is 131v the output is 123-124v (6-7v difference). Is this normal? I am going to put a regulator just in case.
  • Well sure, but are you certain it's thermal? You could test your theory by removing the load - or reducing it significantly - and if it still shuts down it's voltage. If it doesn't then it may be thermal. You can always increase the output voltage of the PPP and that will mean the PPP is trying less hard to regulate - thus creating less heat and strain if that's the case.

    There's a small adjustment screw on the bottom front of the unit - should be pretty obvious as it's the only screw adjustment on the unit. Use the output meter on the front panel and maybe set it 122?
  • Thanks for your prompt response, Paul. The protection going off seems to be thermal. I can hear the fan going on and off sometimes. And it happens not necessarily at 135V (e.g. 130V, for example).

    Would it be worth putting a regulator in front of the PPP and would that harm the sound in any way? I was thinking about an APC Line-R 1200VA regulator. Can you check about the later power cartridges if that could alleviate the problem?

  • Yikes. The PPP cutoff voltage is 135 so it makes sense that it's cutting out. That's a really high fluctuation and can be damaging to your equipment. I am not sure there's a lot we can about that. Some of the later power cartridges may have a higher cutoff, I can check for you.