generous@dgis.daitc.mil (Curtis Generous) (09/20/89)
I have an application where I need to activate a SPDT set of contacts
such that the toggle action does not release after the coil voltage is removed.
And I should then be able to toggle back the contacts with another pulse.
The best analogy is a SPDT RELAY that latches in the activated position until
another pulse comes and toggles it again.
If anyone knows of such a device, or can think of a way of building one....
I hope this makes sense to everyone, I know it does to me :-)
--curtis
--
Curtis C. Generous
DTIC Special Projects Office (DTIC-SPO)
ARPA: generous@daitc.mil
UUCP: {uunet,vrdxhq}!dgis!generouskristi@hpscdc.HP.COM (Kristi Bittner) (09/21/89)
>I have an application where I need to activate a SPDT set of contacts >such that the toggle action does not release after the coil voltage is removed. >And I should then be able to toggle back the contacts with another pulse. >The best analogy is a SPDT RELAY that latches in the activated position until >another pulse comes and toggles it again. >If anyone knows of such a device, or can think of a way of building one.... >Curtis C. Generous Yes, latching relays exist. I've used ones from Aromat Corp. (a US division or subsidiary or whatever of Matsushita) They have a SET coil and a RESET coil, each of which needs approx 10mS pulse. I'm sure other relay vendors make these. If you want to have just a single signal line doing the pulse (toggle effect), it's a little tougher. You either have to have a circuit that will steer the pulses to one coil or the other, or else some of the relays now have ic's built into them, that do the steering for you. (I'm sure this handy little feature costs...) Kristi Bittner hpscdd!kristi@hp-sde hpscdd!kristi@hplabs
larry@kitty.UUCP (Larry Lippman) (09/21/89)
In article <3558@dgis.daitc.mil>, generous@dgis.daitc.mil (Curtis Generous) writes: > I have an application where I need to activate a SPDT set of contacts > such that the toggle action does not release after coil voltage is removed. > And I should then be able to toggle back the contacts with another pulse. > The best analogy is a SPDT RELAY that latches in the activated position until > another pulse comes and toggles it again. There are several options: 1. You can get latching relays with various contacts from such vendors as Guardian, Magnecraft, Potter & Brumfield, etc. These relays fall in two categories, with one category using a separate operate and a separate release coil, and with the other category using a single coil with an escapement mechanism such that the contacts change state alternately with every pulse. These coils are available in both AC and DC voltages. A rotary switch driven by a Ledex rotary solenoid is another form of this device. 2. You can get relays which are magnetically bistable and have an operate and a release winding. The two windings can be connected using the contacts such that a single pulse will alternately operate and relase the relay. The vendors in (1) above also much such magnetically bistable relays; they are also common in miniature sealed can variety as used in military applications. 3. You can build a relay flip-flop with two DPDT relays and two resistors so that a signal (either ground or battery) will alternate the relays, and in effect create the action you desire. However, this approach requires that some power be available at all time to maintain the state of the relays. 4. You can build a relay latching circuit using a single relay with two normally open contacts (one of which is needed for the load) and a single resistor such that alternate momentary application of battery and ground will cause the relay to change state. However, this approach also requires that some power be available at all time to maintain the state of the relay. 5. You can implement (3) or (4) using a large variety of discrete or integrated solid-state circuits. If you want the basic mechanical latching relay, chances are that you can pick one up for a few dollars at a surplus store. <> Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp. <> UUCP {allegra|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> TEL 716/688-1231 | 716/773-1700 {hplabs|utzoo|uunet}!/ \uniquex!larry <> FAX 716/741-9635 | 716/773-2488 "Have you hugged your cat today?"
mmm@cup.portal.com (Mark Robert Thorson) (09/21/89)
Lots of companies make what you describe. Teledyne makes it in a TO-5 can! You might consider whether an SCR can do what you want. An SCR is sort of like a latching relay in that it does not need a sustained control voltage to remain closed.
ee5391aa@hydra.unm.edu (Duke McMullan n5gax) (09/21/89)
>I have an application where I need to activate a SPDT set of contacts >such that the toggle action does not release after the coil voltage is removed. >Curtis C. Generous If you want to do this on the cheap, try to get hold of an old VW headlight relay. These things were used to toggle the high-low headlight beam from an SPST switch. The drawback is that the contacts are SPST, too. You might have to use a second relay (your choice of contact types). Try a wrecking yard first. Flip, flop, d Skinner's algorithm for squaring a number: Divide the number by its reciprocal. Duke McMullan n5gax nss13429r phon505-255-4642 ee5391aa@hydra.unm.edu
arnief@tekgvs.LABS.TEK.COM (Arnie Frisch) (09/21/89)
A quick look in my EEM yielded a list of about 100 companies that make or sell latching relays - which obviously are very popular. Arnold Frisch Tektronix Laboratories
ivan@megatest.UUCP (Ivan Batinic) (09/22/89)
Yes, there are three types which I am familiar with: 1) Mechanical "escapement" toggling relays 2) Toggling relays with builtin transistor-transistor flip-flop 3) Biased "hold magnets" within a reed-relay I had a pet project which was a 6-instruction CPU (ALL RELAYS!) which interfaced to real memory and emulated an M6800 running basic running my 2-half-move look-ahead chess playing program; it was a real screamer (1 move/4.5 days). The relays were either Allen-Bradley, Magna-Latch or Magna-Craft; It has been quite a while now! So I may not have the names exactly right. There are other manufacturers -- look into relays in a parts-master catalog (latching relays). Good luck, they are a dying breed; although the Telephone companies still use them -- you might try salvage companies who carry used telephone equipment too. Ivan ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
nagle@well.UUCP (John Nagle) (09/22/89)
Assuming you really want an electromechanical latching relay,
they do exist. Potter and Brumfield makes a good selection. Call
Newark Electronics (312-784-5100) and get their catalog. Prices
are in the $15 range. These are open-frame relays, and are basically
a solenoid connected to a rachet mechanism. They tend to require substantial
current to drive, like half an amp at 12V. If this is for an application
that involves other electronics, where there's a +5 supply handy, you're
much better off with a flip-flop driving some kind of solid state relay
rather than fooling with these little pieces of machinery. Among other
things, they require a rather long input pulse to switch properly, and
can stop in intermediate positions, especially if not cleaned every
year or so. They are much more troublesome than ordinary relays.
John Nagledeanr@sco.COM (Dean Reece) (09/22/89)
In article <3558@dgis.daitc.mil> generous@dgis.daitc.mil (Curtis Generous) writes: >I have an application where I need to activate a SPDT set of contacts >such that the toggle action does not release after the coil voltage is removed. >And I should then be able to toggle back the contacts with another pulse. >The best analogy is a SPDT RELAY that latches in the activated position until >another pulse comes and toggles it again. >If anyone knows of such a device, or can think of a way of building one.... They do exist. I had one once that had a 6 volt coil and SPST contacts. I connected it to a phototransistor with a straw on its end. The relay contacts were used to gate my TV speaker. Add one reasonably strong flash light and... Ta Da - a commercial (audio) killer for 3 bucks (my TV had no remote). Anyway, back to the subject: The relay used a ballpoint pen style latch mechanism. Each pulse to the coil toggled the contacts. These handy little gidgets are available from various surplus parts vendors. One supplier I know of for sure is All Electronics. I've dealt with them and have been fairly happy with their service. The only problem you may have is that the selection on the surplus market is variable and limited. I can hunt down the address & ph number if you need it. - Hope it Helps ______________________________________________________________________ | Dean Reece Member Technical Staff |"The flames are all long gone | | The Santa Cruz Operation 408/458-1422 | but the pain lingers on" | |___________deanr@sco.com_______________|___________________Pink_Floyd_|
deanr@sco.COM (Dean Reece) (09/26/89)
In <3558@dgis.daitc.mil> generous@dgis.daitc.mil (Curtis Generous) writes: > I have an application where I need to activate a SPDT set of contacts > such that the toggle action does not release after the coil voltage is > removed. > And I should then be able to toggle back the contacts with another pulse. ... > If anyone knows of such a device, or can think of a way of building one.... Yes they exist, and Ive used them before. Specifically, You want a single coil latching relay. The dual coil configuration is more common (where one coil is energised to set, the other is energised to reset). All Electronics Corp. is a surplus parts dealer that I've dealt with many times. They are fairly reliable and represent their merchandise well (unlike some surplus dealers). All Electronics Corp. sells a small assortment of latching relays: Coil: Action: Description: Part Number: Price: -------- ------- ----------------------------------------- ------------- ----- 12 VDC SPDT Dual coil latching relay. LRLY-12DC $2.50 650 Ohms Operates on 7.5 to 26 VDC. -------- ------- ----------------------------------------- ------------- ----- 12 VDC SPDT Electrol latching reed relay. Sealed Case LRLY-121 $2.00 340 Ohms 1+9/16" X 1/2" with P.C Terminals. bipolar Latches open or closed when coil voltage polarity is reversed -------- ------- ----------------------------------------- ------------- ----- 12 VDC 4PDT Aromat # NCP-JPL-2-DC12V PC Board mount LRLY-124 $4.00 90 Ohms flat pack. 1.5" X 1" X .429" -------- ------- ----------------------------------------- ------------- ----- Single 1x SPDT Midtex 24 Vac coil. 3 sets of contacts. IMRLY-24AC $4.50 24 VAC 2x SPST Contacts open or close with each impulse. 10 Amps *** This is probably the one you want *** -------- ------- ----------------------------------------- ------------- ----- All Electronics Corp: 1-800-826-5432 (from areas 818 & 213: 818-904-0524) P.O.Box 567, Van Nuys, CA 91408 - Visa, Master Card, and Discover (no COD) The prices and descriptions above are reprinted without permission from the All Electronics Corp. Spring 1989 Catalog. - I hereby disclaim thee - hope it helps - Dean Reece - ______________________________________________________________________ | Dean Reece Member Technical Staff |"The flames are all long gone | | The Santa Cruz Operation 408/458-1422 | but the pain lingers on" | |___________deanr@sco.com_______________|___________________Pink_Floyd_|
morris@jade.jpl.nasa.gov (Mike Morris) (09/29/89)
Mail addressed to hydra.unm.edu!ee5391aa bounced badly, so pardon the
post:
%>I have an application where I need to activate a SPDT set of contacts such
%>that the toggle action does not release after the coil voltage is removed.
%If you want to do this on the cheap, try to get hold of an old VW headlight
%relay. These things were used to toggle the high-low headlight beam from an
%SPST switch. The drawback is that the contacts are SPST, too. You might have
%to use a second relay (your choice of contact types).
Or get the one out of a junkyard Volvo - my '71 145 had a Bosch SPDT relay -
I had to replace it once, and went to a junkyard. Every 140-series one I saw
had it - and a SPDT is just what you say you need. Watch the coil current,
some of them will draw a amp or so.
--
Mike Morris UUCP: Morris@Jade.JPL.NASA.gov
ICBM: 34.12 N, 118.02 W
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Mike Morris UUCP: Morris@Jade.JPL.NASA.gov
ICBM: 34.12 N, 118.02 W
#Include quote.cute.standard PSTN: 818-447-7052
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