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Xantrex: STXR Problem - Thermal Derating
http://solar-guppy.com/forum/viewtopic.php?f=19&t=432		 Page 2 of 3
Author:  solar408 [ Thu Jun 22, 2006 2:12 pm GMT EndGMT ]
Post subject: 
I just curious. Maybe Xantrex only has parts for the 2500 but when I called in with a problem with my 1500 they just shipped me a new GT2.5. That's why I originally said there was no RMA on these old units, just deals on replacements.
Author:  san_juan_dad [ Fri Jun 23, 2006 12:13 am GMT ErdGMT ]
Post subject: 
Do you have any suggestions on how to get a reasonably sized picture? I previewed a couple and they were so big!
Author:  Solar Guppy [ Fri Jun 23, 2006 12:24 am GMT ErdGMT ]
Post subject: 
In windows, right mouse click on the picture and select "open with", select "paint"

Once in paint, select Image-> stretch/skew and set to 50% for both H&V

Then save as a new file name ... once or twice thru this and you'll get the feel for it

Good luck!
Author:  thevoiceofmoderation [ Tue Jul 03, 2007 1:19 pm GMT ErdGMT ]
Post subject:  Triac for ST2500
I have two ST2500 UPGs. I ended up on this web site because the fan no longer works on one of them. I looked up the spec's on the Q6004L4 and found it rated at 600 volts. Well, the 246 volts showing on my display amounts to 695 volts peak-to-peak.

I have disassembled it yet, but I'm assuming the fan is running on the 240. I think I'll go with the sister part #Q8008LH4 (800 volt) from digikey ($1.71)
Author:  thevoiceofmoderation [ Tue Jul 03, 2007 3:00 pm GMT ErdGMT ]
Post subject:  That Triac issue
True, the peak voltage is RMS/.707 or approximately 340 volts. Peak-to-peak, allowing for the other half Sine excursion is twice that, or 680 volts.

http://en.wikipedia.org/wiki/Alternating_current :wink:
Author:  Matsavol [ Tue Jul 03, 2007 9:46 pm GMT ErdGMT ]
Post subject: 
Hey.. we have a electronics basics debate ongoing here... :lol:

240Vac (sinusoidal, RMS) is about 680V Pk-Pk. The positive half wave peak is at +340V and the negative half way peak at -340V when referenced to Neutral. With full wave (bridge) rectifier the bulk capacitor would be charged to +340Vdc (minus 2x the diodes forward voltage drop). The only case you would be seeing the full peak-to-peak DC is with some voltage doubler rectification circuit where each half of the sine waves are rectified in their own capacitor and the capacitors are connected in series. (This is how the 120/240V voltage selector switch works in PC power supplies, for example. It changes the circuit from voltage doubler to full bridge and vise versa.)

Maybe it is now more clear... or not? :roll:
Author:  Matsavol [ Wed Jul 04, 2007 8:28 pm GMT EthGMT ]
Post subject: 
I guess you guys forgot International aspect: In UK they have one phase 240Vac. In Europe the most common voltage is 230Vac.

In the US the 240Vac is really two phase (or line) 120Vac, where the phases are 180 degrees apart. This makes it behave like 240Vac (between phases, that is).
Author:  mike90045 [ Wed Jul 04, 2007 10:06 pm GMT EthGMT ]
Post subject: 
http://www.sengpielaudio.com/calculator-db-volt.htm

(half way down has a pretty RMS - PP converter)

I don't know if this is in Euro volts or American volts :o
Author:  thevoiceofmoderation [ Mon Jul 09, 2007 4:08 pm GMT EthGMT ]
Post subject:  thermal derate
Mr Guppy sir,

Can you tell me what the formula for derating is on the ST2500? I'm considering using a snap-action thermal switch attached to the heat sink to control the fan and I want it to kick-in before derating begins.

Thanks
Author:  Solar Guppy [ Mon Jul 09, 2007 8:06 pm GMT EthGMT ]
Post subject: 
The derating starts at 60C on the heat sink .. I would suggest a bit lower and you sould be ok .. keep in mind you will be running full on, which is pretty loud!
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