There are single coil and two coil relays that us a
mechanism to accomplish a latching function.
Any full-line relay catalog will show them.
I've seen the one-coil version called an impulse relay,
a rotary relay, a latching relay and a few other choice
names when the mechanism gets dirty and doesn't
work.
Mike WA6ILQ
At 09:20 AM 10/22/08, you wrote:
Any body know what is the name of relay that have a gear on the
side, every time the relay energize once it turn the gear and lock
the relay position from normally close
to open and open to close, I have one of the relay that work that
way long time ago, maybe its still available today.
73
Camilo
----- Original Message -----
From: <mailto:[EMAIL PROTECTED]>Al Wolfe
To: <mailto:Repeater-Builder@yahoogroups.com>Repeater-Builder@yahoogroups.com
Sent: Wednesday, October 22, 2008 10:25 AM
Subject: [Repeater-Builder] Re: Shutting Down Battery Back up
Scott,
You are of course correct about hooking the PA directly to the battery,
there being no reason to disconnect it.
There are undoubtedly many good reasons to consider a more sophisticated
disconnect method than the simple relay circuit described when the ulimate
in power saving is needed. However, I wonder what percentage of the folks on
this list have the technical acumen to design a circuit like this, let alone
trying to gather all the parts for it.
The cutout circuit of the solar charge controller you mention does look
interesting and the kit for $55 might easily be adaptable to be used in a
repeater disconnect application.
However, I still feel that the extremely simple relay circuit I
described will do the job as it has for me in several applications for many
years. With only three or four parts there is very little to fail. When the
box it up on the hill I don't want to have to run up there every time there
is a nearby lightning strike.
The 100 ma. figure is typical of some of the Rat Shack relays. There are
many that pull much less current available.
Al, K9SI
> Re: Shutting Down Battery Back up
> Posted by: "Scott Zimmerman"
<mailto:n3xcc%40repeater-builder.com>[EMAIL PROTECTED] scottn3xcc
> Date: Tue Oct 21, 2008 8:34 am ((PDT))
>
> If you are concerned about your batteries lasting as long as possible when
> running on backup, I would NOT use a relay. Even at 100ma of current draw,
> that's a LOT of current in a backup / solar situation. Since the RF PA
> only
> draws current when in transmit, (Class 'C') you can hook it directly to
> the
> battery all the time when line voltage is not present. This can be done
> easily with normally closed contacts on a relay that is fed from the AC
> line.
>
> Have a look at the cutout circuitry of this solar charge controller:
>
<http://www.solorb.com/elect/solarcirc/spc3/>http://www.solorb.com/elect/solarcirc/spc3/
>
> They use a voltage comparator to do the switching. I would think a circuit
> could be designed that simply used a 10V zener diode and a transistor to
> feed the power FET. Probably until you would go through all of that, you
> could have the comparator circuit built and ready to go.
>
> The moral of the story is that a comparator and power FET switch would
> draw
> FAR less current than using a relay coil. You could also set the
> comparator
> EXACTLY where you want the circuit to turn off. Be sure that the
> hysteresis
> resistor is a small enough value so that when the circuit cuts out with
> the
> transmitter active, it won't turn back on when the battery voltage
> recovers.
> Of course, this could be tailored to taste.
>
> Scott
>
> Scott Zimmerman
> Amateur Radio Call N3XCC
> 474 Barnett Rd
> Boswell, PA 15531
>
> ----- Original Message -----
> From: "Al Wolfe" <<mailto:k9si%40arrl.net>[EMAIL PROTECTED]>
> To:
<<mailto:Repeater-Builder%40yahoogroups.com>Repeater-Builder@yahoogroups.com>
> Sent: Tuesday, October 21, 2008 9:15 AM
> Subject: [Repeater-Builder] Re: Shutting Down Battery Back up
>
>
>> Don,
>> Low battery voltage shut-down can be done quite simply using three or
>> four parts: a normally open contact relay, a resistor, and a cap. The
>> battery goes to one side of the N. O. contact and the load (repeater?),
>> power supply, and relay coil to the other N. O. contact. The other side
>> of
>> the coil goes to ground via a resistor. The resistor value is determined
>> empirically and should be selected so that the relay will drop out at
>> about
>> ten volts or whatever you decide is the minimum useful voltage. Use a
>> variable DC supply to determine the proper resistance value.
>>
>> You should be able to find a 12 volt relay that needs less than 100
>> ma.
>> through the coil. An appropriate resistance might be 22 or 27 ohms for
>> this
>> relay.
>>
>> A 1000 MFD cap should be in parallel with the resistor so that when
>> power is restored from the power supply, full voltage is applied to the
>> relay coil for a time to energize it. The resistor also lowers the power
>> used by the relay to a degree. The ubiquitous chatter diode across the
>> relay
>> coil is a good idea as well.
>>
>> I have used this method for several applications at work and it is
>> virtually fool proof.
>>
>> Good luck,
>> Al, K9SI
>>
>>
>>
>>> Now the question and I have not seen this talked about I would
>>> assume all I would need is a Normally closed Relay and as the Voltage
>>> dropped below >a Certain Level it would open and just break the
>>> connection to the Battery back up , Is this the way to do it
>>
>>
>>> Thanks
>>
>>
>>> Don KA9QJG
