I would have gladly run the supply loaded to 28 amps if the resistors could take it. They couldn't. They were heating the room after several minutes, and took half an hour to cool off after that. I did the best I could with the equipment available. I need about 400 watts-worth of load to test these things properly.
I step-started the repeater after putting in the working power supply, but it didn't need to be done that way. Astron never responded to my e-mail from Friday, so I'll be rattling their cage Tuesday to see how their warranty procedure works and if it's even worth sending the unit back to them. Bob M. ====== --- skipp025 <[EMAIL PROTECTED]> wrote: > > "Bob M." <[EMAIL PROTECTED]> wrote: > > Well, I know that the transformer makes heat all > by > > itself, but in the repeater cabinet, a fan is > blowing > > directly on the back of the supply and I've never > had > > anything get hot inside in over 5 years of > operation > > (except for the MaxTrac exciter running at 6 > watts, > > but the fan keeps it cool too). > > Even with the fan... if you're pulling 25 amps from > the > supply the heat sinks will get warm.... real warm. > The > fan at best can only keep it from getting real hot. > So > hot you couldn't keep your hand on the heat sink > metal. > > > I also load-tested the supply that's currently > > running, with a pair of 1 ohm resistors in > parallel. > > They got really hot after several minutes while > the > > supply itself stayed ice cold. > > How about 45 minutes in operation at 25 amps load? > Several > minutes doesn't really cut the mustard. > > > I did discover that the supplies don't like being > > powered up with a 1/2 ohm load across the output. > I > > only got 5V/10A; I presume that was a foldback of > some > > kind. When I disconnected the load, everything > went > > right back to 14V. With the supply running, the > only > > thing that changed when I reconnected the load was > the > > ammeter went from 0 to 28. The voltage at the > output > > terminals only dropped a few dozen millivolts. > > Bob M. > > The astron supply regulator design does not power up > > well into high current demand. The variable "vls" > supply > is even more sluggish. There are 2 step start > methods used > by some people to deal with this "design quirk". > s. ____________________________________________________________________________________ Sucker-punch spam with award-winning protection. Try the free Yahoo! Mail Beta. http://advision.webevents.yahoo.com/mailbeta/features_spam.html
