Forum Top Banner Ad

Collapse

Ebay Classic organs

Collapse

Announcement

Collapse
No announcement yet.

Magnet valves

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Magnet valves

    Hello,
    I'm looking to buy some magnet valves but I am having a hard time finding options.
    I see that PetersonEMP sells some but I'd like to see what else is out there and I don't know where to look. Does anyone have any suggestions?

    Also, I see that they are available in different resistances like 40 Ohm and 90 Ohm. What should be considered when choosing a resistance?

    Thank you!

    Click image for larger version  Name:	Peterson Valve.jpg Views:	17 Size:	7.9 KB ID:	798732
    Last edited by Conner Blase; 04-26-2022, 02:01 PM.

  • #2
    https://www.electricsolenoidvalves.c...s-measurement/

    According to the source above, the resistance helps you predict how much current the solenoid will pull. At 12 volts, the 90 ohm one will pull about 100 mA, whereas the 40 ohm one will pull about 250 mA. Of course, this will vary with room temperature, the value of your bridge rectifier, details of the power supply, current loss by the length of wiring, etc. and this assumes DC current. If you're replacing faulty ones, make sure you use solenoids that have the same characteristics as the ones you're replacing. The power supply or how the coils are wired may also be burning out the coils, so this has to be checked carefully as well.

    These are high amperage's, especially if you are powering a lot of solenoids at once, so make sure you observe all the safety recommendations and have someone who knows how to work with high currents! When wiring, make sure you use low enough gauge wire, and wire carefully. Protect yourself with a grounding strap, and use fuses if possible.

    Current: Allen 225 RTC, W. Bell reed organ, Lowrey TGS, Singer upright grand
    Former: Yamaha E3R
    https://www.exercisesincatholicmythology.com

    Comment


    • myorgan
      myorgan commented
      Editing a comment
      Originally posted by Larason2
      It doesn't work like a traditional resistor, because of the conversion of energy, rather than dissipating energy as heat.
      Thank you for the clarification. Your explanation makes more sense than how I was thinking of it (i.e. dissipation, etc.). Now I know why I don't ever want to be an electrical engineer. Hurts me in some of my endeavors, but I always have others I can ask.

      Michael

    • j reimer
      j reimer commented
      Editing a comment
      Larason2's current figures are in the right direction, but are understated for some reason. It is the article's "DC Coil Current Characteristics" section which is relevant for most organ applications. So after the initial short (a few milliseconds) period, we are talking about DC conditions. i.e. Current = Voltage / Resistance. 90 ohms will yield 133 mA, and 40 ohms, 300 mA. All at 12 volts.

    • Larason2
      Larason2 commented
      Editing a comment
      As per the article above, I assumed a 1.5 volt voltage drop because of the bridge rectifier in the example. I rounded to the nearest 50 mA, so actually 117 mA and 263 mA to be more precise.

  • #3
    In addition to the points made by @Larson2, there are some other points to consider. The diameter of the valve and the wind pressure are also factors in the resistance decision. For modest wind pressures, say 3.5" and valve diameters of 0.75", 90 ohm magnets should be sufficient. You may have to consider lower values for larger valve diameters, which may be needed in the 8' octave, or higher wind pressures.

    Also, if the valves are driven by a solid-state relay, you want to make sure that the output stage can handle the expected current. Relay specs will typically indicate what value of load they can handle.

    Doug

    Comment


    • #4
      Being that I am a pipe organ builder and a electrical engineer, we need to know what the valves are going to be used for. What is the opening size and the wind pressure. Normally for a pipe chest, one can use the 90 ohm coils with a valve size to 5/8" on about 4" of water pressure. Larger valves will need a lower resistance coil down to 24 ohm. Theater organs are voiced at much higher pressure and can use up to 30 to 50" pressure and will need much smaller resistance coils. Hope this helps.

      Michael

      Comment


      • #5
        I'm still looking for a place to get the valves from if anyone has any suggestions.

        Comment


        • Pipeorganbuilder
          Pipeorganbuilder commented
          Editing a comment
          Sorry, I have been away for a few days and have not been able to follow up with your posts.
          If you can supply me with a number of the valves you need, I may very well have what you need and if not will be glad to order them for you. Sad that my suppliers do not sell to the public. Same with Allen organ company. Parts should be available to anyone needing them in my opinion.
          Michael

        • Conner Blase
          Conner Blase commented
          Editing a comment
          Pipeorganbuilder, I sent you a private message if you haven't seen it.

      • #6
        Originally posted by Conner Blase
        I'm still looking for a place to get the valves from if anyone has any suggestions.
        Originally posted by Pipeorganbuilder View Post
        Being that I am a pipe organ builder and a electrical engineer, we need to know what the valves are going to be used for.
        @Pipeorganbuilder, Michael, do you care to share any of your known sources? I know some pipe organ suppliers have closed recently, and others do not sell to individuals. However, I don't know any to share beyond those who have already been named.

        Conner Blase, have you answered Michael's question about how the valves will be used? The answer will help Michael help you.

        Michael
        Way too many organs to list, but I do have 5 Allens:
        • MOS-2 Model 505-B / ADC-4300-DK / ADC-5400 / ADC-6000 (Symphony) / ADC-8000DKC
        • Lowrey Heritage (DSO-1)
        • 11 Pump Organs, 1 Pipe Organ & 7 Pianos

        Comment


        • Conner Blase
          Conner Blase commented
          Editing a comment
          I'm building a small test organ to get my feet wet before I jump into a much bigger project down the road.
          It'll run on 2" of pressure with holes an inch or less in diameter.

          This video was my inspiration
          https://youtu.be/XeJpEhwZcqQ

      • #7
        Organsupply.com stocks Reisner magnet valves: http://www.organsupply.com/assets/Br...r-Tri-Fold.pdf
        -------

        Hammond M-102 #21000.
        Leslie 147 #F7453.
        Hammond S-6 #72421

        Comment


        • myorgan
          myorgan commented
          Editing a comment
          GTC,

          They only sell to dealers. They've refused to sell items to me (as an organ owner) more than once.

          Michael

        • gtc
          gtc commented
          Editing a comment
          Bummer. I wonder who they'll sell to when there are no dealers left?

        • myorgan
          myorgan commented
          Editing a comment
          Great point gtc!

          Michael

      • #8
        I'd like to come back to some of the safety precautions brought up by Larason2. Although wearing a ground strap is a good idea when working with chips sensitive to static electricity, that is the only time it should be worn. Should you be wearing a ground strap on your right wrist and then you touch 120 V with your left hand, the current flow would be straight across the heart and potentially deadly. It's better to be wearing rubber soles to reduce the chances of being grounded when touching a dangerous voltage. BTW, I've worked on many circuit boards without resorting to a ground strap and have yet to destroy a chip. But it can happen. A student of mine once destroyed an 8085 microprocessor chip by touching it after shuffling across a concrete floor. The chip was easily replaced and it was a perfect teaching moment.

        A precaution not mentioned is to make sure you are not wearing a ring or a watch with a metal bracelet when working around high currents. Shorting a 70 A source with a gold ring will instantly turn it red hot and cause a severe burn.

        And yes, do use fuses as recommended by the manufacturers of organ switching systems and combination actions. I always hook up the power coming from a high current source directly to a fuse block and then subdivide it into sub circuits each carrying at most 10 A. I like the marine fuse blocks that may be found on Amazon. They have the capacity, are very rugged and have built in LEDs to indicate when one of the automotive fuses has blown. More than once, it has let me instantly spot a problem when a circuit fails.

        The nice thing about working around organ voltages, of 15 V, say is that there is no electrocution risk as long as the power supply is working properly.

        Comment


        • edkennedy
          edkennedy commented
          Editing a comment
          Ground strap - A proper ground strap has a high internal resistance (about 1 Mohm) which will dissipate static electricity, but will not allow hazardous current to flow. There is no safety issue while wearing one. Rings and metal watch bands can, as stated above, be very dangerous if they short across the power terminals.

        • Larason2
          Larason2 commented
          Editing a comment
          That's interesting Ed. You are right about the grounding strap. I just tested mine, and it is very close to 1 Mohm. So it seems I have been using it wrong all this time. The main thing is to make sure the organ is well grounded! And of course, to always be careful.

      • #9
        Coenraads is right that any safety device has to be used properly to work. The whole idea of a safety strap is current goes along the strap and not into your heart. It's true that current can go into your left hand through your chest to the safety strap, but it can do that if you're not wearing a safety strap too. To my knowledge, no one has ever been killed by less than 50 A, and you're unlikely to meet that much current in an organ. However I've never heard on anyone shocked with 10A who has enjoyed the experience!

        So to be safe, even if you have safety equipment, you have to be careful. A situation I use the safety strap is discharging high value capacitors, and I make sure the hand that has the strap attaches the clip!

        If wiring up magnets, do all the wiring without the power supply attached, double check everything, then attach the power supply. If after testing there are problems, remove the power supply and check if possible. If you have to check something with live 10A power, that's when I would use the safety strap, and do the testing with the hand that has the strap. If you can avoid that situation though, that would be more ideal!

        Like Coenraads, I never use a safety strap with sensitive chips. I just ground myself before I touch them!

        Current: Allen 225 RTC, W. Bell reed organ, Lowrey TGS, Singer upright grand
        Former: Yamaha E3R
        https://www.exercisesincatholicmythology.com

        Comment


        • #10
          Conner Blase Peterson has a chart that shows you which magnets to use based on the toe hole size and the wind pressure. It is here: http://www.petersonemp.com/manuals/m...08-14-2014.pdf

          As far as I know, Peterson is the only company that will sell directly to a person. However, I suggest reaching out in one of the pipe organ garage sale groups on Facebook because many people there generally have magnets to sell.

          Comment


        • #11
          As a physics teacher, I used to teach my class a lesson called, "How to electrocute yourself." I would put a stuffed monkey on a stand and hang a neon bulb around his neck. Then we would probe various situations with the two leads coming from the bulb to see what would make it light up. If the neon bulb lights up, there is a danger of electrocution. A toaster was my favourite thing to test. Surprisingly, a toaster when turned off can still be lethal when you stick a fork inside. And there is a reason why toasters are never grounded.

          Does current kill? Not in and of itself. I'll happily touch the terminals of a 12 V car battery even though it is capable of providing a current of hundreds of amperes. Even if the starter motor is cranking, and the wires are carrying one or two hundred amperes, there is still no danger of electrocution.

          Does voltage kill? Again, not in and of itself. I'll (not so happily) touch the dome of a Van de Graaf generator capable of generating an electric potential of one million volts. It may "tickle" but it won't kill since the current is of the order of microamps.

          What kills is the right combination of current and voltage. As little as 100 mA across the heart can cause death but that current must get inside your body first. It takes an electrical potential of more than 70 or 80 volts for electricity to overcome skin resistance. Thus a household socket capable of providing 15 A at 120 V can kill and fuses provide zero protection. A GFCI (Ground Fault Circuit Interrupter) works quite differently and can be an effective safety device under certain circumstances.

          We tend to think of a nine volt battery as harmless, but connect a couple of dozen in series and they will be lethal. On the other hand, working on an organ with a 70 A, 15 V power supply can be done safely with the power on as long as you don't inadvertently create a short circuit which will cause the wire creating the short to glow red hot instantly and is quite capable of causing a serious burn or even a fire. My habit when using a test probe on a live organ circuit is to connect a 10 ohm, wire wound resistor in series with my test probe. This will still let enough current flow to turn on a chest magnet, say, yet provide complete protection against the possibility of a dangerous current.

          Or to put it simply: high voltages cause death while high currents cause fires.

          Comment


          • #12
            When I was trained in electronics, we were taught that, under certain conditions, current as low as 50mA in a path across the chest can cause ventricular fibrillation, which is a life-threatening condition.

            In my neck of the woods, where mains voltage is 240, toasters are most definitely grounded and, because of nuisance triggering resulting from characteristics of the MEN system, ELCBs are no longer used. RCDs are used instead.

            That aside, my advice to anyone is that unless you are formally trained in safe electrical working practice, do not attempt to work on mains powered equipment.
            Last edited by myorgan; 05-03-2022, 07:10 PM. Reason: Correct post per gtc's request.
            -------

            Hammond M-102 #21000.
            Leslie 147 #F7453.
            Hammond S-6 #72421

            Comment

            Working...
            X