Sorry, Ron, I disagree with the relay idea. If it's critical that the radio
power supply be up all the time, then run it in the emergency circuits, which
ARE active all the time. Our main ambulance radio and our maintenance repeater
are on emergency power, as I specificied and coordinated the istallation of
both of them myself.
The only switching occurs when the power goes down, all receptacles (both
white and red are now dead) then the generators fire up within 15 seconds,
stabilize, and transfer the feed of the red receptacles from the outside
utility to the generators. Power switches back automatically after utility
power has been restored and stays up for at least 5 continuous minutes with no
dropouts. Then the generators run on cool-down for at least 10 minutes.
My CBET rating means I'm certified as a Biomedical Equipment Technician on
6 levels of the proper care and feeding of medical instrumentation, including
power supplies. :-)
And, Laryn, I re-read your initial statement. You had 2 repeaters AND a
computer on the same circuit, and it tripped? Again, what all was on that
circuit? If the printer was also on that same circuit, you need to get it off
the red and on the white. But even 100 watt repeaters with linear supplies
should only draw 4 amps each on full load, plus 4 for the PC and display.
Something else is on the circuit. Shame you can't take pictures. Check with the
hospital electrician and see what's up. Good luck!
Ray
Ron Wright <[EMAIL PROTECTED]> wrote:
Laryn,
Your thinking is good. A simple relay, 3 pole/double throw would do what you
want and power the relay coil with your normal AC power. When it goes the relay
drops out and connects the repeater to the RED emergency outlet.
As someone else suggested switch all 3 wires of hot, neutral and safety ground
just to make sure you are not connecting something that you should not.
Some suggest runing the repeater on the RED emergency outlet and all else on
the normal outlet. You need to check to see if this RED outlet is powered all
the time and not just when the gen/emergency power is running. Since it goes to
the generator it might not be. Easy to check by plugging a lamp under normal
power conditions.
The only problems I see is the sudden switching back and forth that might occur
quickly serval times in a short period. Like turning on/off the repeater power
supply rapidly, but don't think this would be an issue.
73, ron, n9ee/r
>From: Laryn Lohman
>Date: 2008/07/13 Sun PM 08:17:51 EDT
>To: [email protected]
>Subject: [Repeater-Builder] Switching a Repeater Betwen AC Sources
>
>We have two repeaters, plus an IRLP computer, on one emergency-fed
>circuit at a hospital. There are normally no problems with this.
>During a recent storm, the AC panel circuit breaker tripped, taking
>everything down in the middle of our Skywarn net.
>
>There are two receptacles near our equipment. One is normal power,
>the other is the red Critical Power receptacle. What problems would
>anyone see if we would feed everything from the normal power circuit,
>and if it would ever trip off, switch to the red receptacle. That
>way, if lightning trips the normal circuit, we would instantly feed
>our equipment from the red receptacle.
>
>This sounds so simple, and I'm inclined to build such a setup, but am
>I missing something obvious that could cause problems? Any better ideas?
>
>Laryn K8TVZ
>
>
