| Page 1 of 2 | 1 | 2 |
|
|
Re-winding solenoids.
Just a few abstract thoughts here. It makes sense to me,
but then I've been known to over look the obvious on occasion. ;-) I have a solenoid coil that actuates a large 3-pole contactor. A short pulse to pull up on a lever that will toggle it from on position to another, and back. Making measurements of the solenoid coil, although potted in epoxy, yields a few measurements and a couple of guesses. http://www.pronine.ca/multind.htm Coil form 1" diameter, 1-3/8" width and 1.5" depth. Going backwards on a solenoid coil java script, yields a matching 125 mH inductance (as measured) and 95 ohm DCR (as measured) for 2500 turns of #30 AWG which will fill the bobbin. This a 480 VAC actuator. Am I headed in the right direction if I assume the key factor here is ampere turns? Not allowing for the added inductance by a movable core, this has an impedance of roughly 100 ohms. So that works out to 4.8 amps or 12,000 ampere turns. Substituting 2000 turns of #28 AWG yields 80 mH, and 42 Ohms. And subsequently roughly 12,000 ampere turns at 240 VAC. Putting 240 VAC across the 480 VAC coil yields only 6,000 ampere turns and obviously is NOT enough to actuate the contactor transfer mechanism. The reason I'm curious is that ASCO seems to think that the replacement coil for this is worth $585, although they will sell it as the "sale price" of only $421.80. Jeff-1.0 The other other one -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
Jeffrey Angus wrote:
Just a few abstract thoughts here. It makes sense to me, but then I've been known to over look the obvious on occasion. ;-) I have a solenoid coil that actuates a large 3-pole contactor. A short pulse to pull up on a lever that will toggle it from on position to another, and back. Making measurements of the solenoid coil, although potted in epoxy, yields a few measurements and a couple of guesses. http://www.pronine.ca/multind.htm Coil form 1" diameter, 1-3/8" width and 1.5" depth. Going backwards on a solenoid coil java script, yields a matching 125 mH inductance (as measured) and 95 ohm DCR (as measured) for 2500 turns of #30 AWG which will fill the bobbin. This a 480 VAC actuator. Am I headed in the right direction if I assume the key factor here is ampere turns? Not allowing for the added inductance by a movable core, this has an impedance of roughly 100 ohms. So that works out to 4.8 amps or 12,000 ampere turns. Substituting 2000 turns of #28 AWG yields 80 mH, and 42 Ohms. And subsequently roughly 12,000 ampere turns at 240 VAC. Putting 240 VAC across the 480 VAC coil yields only 6,000 ampere turns and obviously is NOT enough to actuate the contactor transfer mechanism. The reason I'm curious is that ASCO seems to think that the replacement coil for this is worth $585, although they will sell it as the "sale price" of only $421.80. Jeff-1.0 The other other one Beware that some coils are dual coils with diodes potted in them. WHen a diode fails in one of these, they tend to generate some noise when energized. This is because one coil is pushing both directions against the other that isn't. Basically what this means is, the coil is designed to operate in a DC state. What we have done in the past if we suspected a shorted diode in one of these types is to put a bridge rectifier in front of it. But I can tell you this, if the construction of core around this coil in the device that is using it has a laminated type layers, chances are, you have a simple coil and there is some form of shading device near the contact point where the accouter makes contact with it. What is this thing? A ratcheting three position device? being ASCO, it sounds like some kind of valve. Jamie |
Re-winding solenoids.
On Sun, 16 Oct 2011 15:48:07 -0500, Jeffrey Angus
wrote: This a 480 VAC actuator. Make, model, and photograph? Is there a copper D-ring on the top end of the solenoid? If the coil it dead, try disolving the epoxy. http://www.esslinger.com/attack.aspx It will also make a useful coil form. If you know the core dimensions and the wire guage, you can estimate the number of turns. The reason I'm curious is that ASCO seems to think that the replacement coil for this is worth $585, although they will sell it as the "sale price" of only $421.80. Check eBay? -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Re-winding solenoids.
On 10/16/2011 4:33 PM, Jamie wrote:
Beware that some coils are dual coils with diodes potted in them. WHen a diode fails in one of these, they tend to generate some noise when energized. This is because one coil is pushing both directions against the other that isn't. Basically what this means is, the coil is designed to operate in a DC state. What we have done in the past if we suspected a shorted diode in one of these types is to put a bridge rectifier in front of it. But I can tell you this, if the construction of core around this coil in the device that is using it has a laminated type layers, chances are, you have a simple coil and there is some form of shading device near the contact point where the accouter makes contact with it. What is this thing? A ratcheting three position device? being ASCO, it sounds like some kind of valve. This is a simple multi-layer solenoid. It is fed with 480 VAC via an external bridge rectifier. It is a pull up actuated 100 amp 3-pole contactor. It is physically identical to this one, with the excption of being 3-poles rather than 2. http://www.ebay.com/itm/130520617745 The solenoid is at the top left of the contactor with the bridge rectifier on the side. Jeff-1.0 -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
On 10/16/2011 5:14 PM, Jeff Liebermann wrote:
On Sun, 16 Oct 2011 15:48:07 -0500, Jeffrey wrote: This a 480 VAC actuator. Make, model, and photograph? A similar model. 2-pole 120 VAC rather than 3-pole 480 VAC. http://www.ebay.com/itm/130520617745 This is the coil itself from ASCO. http://www.ascoparts.com/343500-063.html Is there a copper D-ring on the top end of the solenoid? Nope. If the coil it dead, try disolving the epoxy. http://www.esslinger.com/attack.aspx It will also make a useful coil form. Coil works perfectly with 480 VAC applied to the bridge recitfier. My task is to wind a new coil that will work at 240 VAC. If you know the core dimensions and the wire gauge, you can estimate the number of turns. I did that, see the initial posting. Using DC resistance, physical size and measured inductance. The reason I'm curious is that ASCO seems to think that the replacement coil for this is worth $585, although they will sell it as the "sale price" of only $421.80. Check eBay? They have the contactors available from $750 and up, and complete units for $1500 and up. No solenoids only. Jeff-1.0 -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
On Oct 16, 1:48*pm, Jeffrey Angus wrote:
Just a few abstract thoughts here. It makes sense to me, but then I've been known to over look the obvious on occasion. ;-) I have a solenoid coil that actuates a large 3-pole contactor. A short pulse to pull up on a lever that will toggle it from on position to another, and back. Making measurements of the solenoid coil, although potted in epoxy, yields a few measurements and a couple of guesses. http://www.pronine.ca/multind.htm Coil form 1" diameter, 1-3/8" width and 1.5" depth. Going backwards on a solenoid coil java script, yields a matching 125 mH inductance (as measured) and 95 ohm DCR (as measured) for 2500 turns of #30 AWG which will fill the bobbin. This a 480 VAC actuator. Am I headed in the right direction if I assume the key factor here is ampere turns? Not allowing for the added inductance by a movable core, this has an impedance of roughly 100 ohms. So that works out to 4.8 amps or 12,000 ampere turns. Substituting 2000 turns of #28 AWG yields 80 mH, and 42 Ohms. And subsequently roughly 12,000 ampere turns at 240 VAC. Putting 240 VAC across the 480 VAC coil yields only 6,000 ampere turns and obviously is NOT enough to actuate the contactor transfer mechanism. The reason I'm curious is that ASCO seems to think that the replacement coil for this is worth $585, although they will sell it as the "sale price" of only $421.80. do you see the part number on this list? Seems considerably cheaper: http://www.valvestore.com/products.asp?dept=1448 |
Re-winding solenoids.
Jamie wrote: Jamie wrote: Jeffrey Angus wrote: On 10/16/2011 5:14 PM, Jeff Liebermann wrote: On Sun, 16 Oct 2011 15:48:07 -0500, Jeffrey wrote: This a 480 VAC actuator. Make, model, and photograph? A similar model. 2-pole 120 VAC rather than 3-pole 480 VAC. http://www.ebay.com/itm/130520617745 This is the coil itself from ASCO. http://www.ascoparts.com/343500-063.html Is there a copper D-ring on the top end of the solenoid? Nope. If the coil it dead, try disolving the epoxy. http://www.esslinger.com/attack.aspx It will also make a useful coil form. Coil works perfectly with 480 VAC applied to the bridge recitfier. My task is to wind a new coil that will work at 240 VAC. If you know the core dimensions and the wire gauge, you can estimate the number of turns. I did that, see the initial posting. Using DC resistance, physical size and measured inductance. The reason I'm curious is that ASCO seems to think that the replacement coil for this is worth $585, although they will sell it as the "sale price" of only $421.80. Check eBay? They have the contactors available from $750 and up, and complete units for $1500 and up. No solenoids only. Jeff-1.0 Why don't you use a simple step up transformer for the coil? you won't need a large one. JAmie To add to that, a 1:1 control transformer of a very small size can be wired as a buck boost to operate that coil. Tell him something he DOESN'T already know. -- You can't have a sense of humor, if you have no sense. |
Re-winding solenoids.
Jeffrey Angus wrote:
On 10/16/2011 5:14 PM, Jeff Liebermann wrote: On Sun, 16 Oct 2011 15:48:07 -0500, Jeffrey wrote: This a 480 VAC actuator. Make, model, and photograph? A similar model. 2-pole 120 VAC rather than 3-pole 480 VAC. http://www.ebay.com/itm/130520617745 This is the coil itself from ASCO. http://www.ascoparts.com/343500-063.html Is there a copper D-ring on the top end of the solenoid? Nope. If the coil it dead, try disolving the epoxy. http://www.esslinger.com/attack.aspx It will also make a useful coil form. Coil works perfectly with 480 VAC applied to the bridge recitfier. My task is to wind a new coil that will work at 240 VAC. If you know the core dimensions and the wire gauge, you can estimate the number of turns. I did that, see the initial posting. Using DC resistance, physical size and measured inductance. The reason I'm curious is that ASCO seems to think that the replacement coil for this is worth $585, although they will sell it as the "sale price" of only $421.80. Check eBay? They have the contactors available from $750 and up, and complete units for $1500 and up. No solenoids only. Jeff-1.0 Why don't you use a simple step up transformer for the coil? you won't need a large one. JAmie |
Re-winding solenoids.
Jamie wrote:
Jeffrey Angus wrote: On 10/16/2011 5:14 PM, Jeff Liebermann wrote: On Sun, 16 Oct 2011 15:48:07 -0500, Jeffrey wrote: This a 480 VAC actuator. Make, model, and photograph? A similar model. 2-pole 120 VAC rather than 3-pole 480 VAC. http://www.ebay.com/itm/130520617745 This is the coil itself from ASCO. http://www.ascoparts.com/343500-063.html Is there a copper D-ring on the top end of the solenoid? Nope. If the coil it dead, try disolving the epoxy. http://www.esslinger.com/attack.aspx It will also make a useful coil form. Coil works perfectly with 480 VAC applied to the bridge recitfier. My task is to wind a new coil that will work at 240 VAC. If you know the core dimensions and the wire gauge, you can estimate the number of turns. I did that, see the initial posting. Using DC resistance, physical size and measured inductance. The reason I'm curious is that ASCO seems to think that the replacement coil for this is worth $585, although they will sell it as the "sale price" of only $421.80. Check eBay? They have the contactors available from $750 and up, and complete units for $1500 and up. No solenoids only. Jeff-1.0 Why don't you use a simple step up transformer for the coil? you won't need a large one. JAmie To add to that, a 1:1 control transformer of a very small size can be wired as a buck boost to operate that coil. Jamie |
Re-winding solenoids.
On 10/16/2011 8:05 PM, Jamie wrote:
Why don't you use a simple step up transformer for the coil? you won't need a large one. Um, however briefly, the transformer needs to supply 5.2 amps at 480 volts to successfully energize the coil. That's 2500 VA Even a 500 VA control transformer that I have sags too much to properly actuate the transfer switch. Jeff-1.0 -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
On 10/16/2011 8:12 PM, Jamie wrote:
To add to that, a 1:1 control transformer of a very small size can be wired as a buck boost to operate that coil. As I mentioned previously, the solenoid requires a 5.2 amp pulse to properly actuate the contactor mechanism. With a 240/240 control transformer wired up in boost mode that would need at 1000 VA transformer as a bare minimum. Jeff-1.0 -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
On 10/16/2011 8:01 PM, Michael A. Terrell wrote:
Tell him something he DOESN'T already know. Heh, thanks Michael. What I don't know and would like to know is if my thinking with regards to ampere turns is correct. Because I CAN wind a new solenoid coil with a 1/2 pound spool of wire for about $20. Jeff-1.0 -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
Jeffrey Angus wrote:
On 10/16/2011 8:05 PM, Jamie wrote: Why don't you use a simple step up transformer for the coil? you won't need a large one. Um, however briefly, the transformer needs to supply 5.2 amps at 480 volts to successfully energize the coil. That's 2500 VA Even a 500 VA control transformer that I have sags too much to properly actuate the transfer switch. Jeff-1.0 I find it hard to believe that coil is using that much? Are you sure it's in proper working order? We have 500 amp contactors with 120V coils that only require about 2 amps to pull in. Something just does not sound right, but what ever. Jamie |
Re-winding solenoids.
On 10/16/2011 8:34 PM, Jamie wrote:
I find it hard to believe that coil is using that much? Are you sure it's in proper working order? We have 500 amp contactors with 120V coils that only require about 2 amps to pull in. Something just does not sound right, but what ever. Yes I am sure. And yes I know what some contactors take to actuate the coils in a steady state holding condition. To repeat. This is a pulsed operation. The auxiliary contacts on the transfer switch contactor interrupt the source from the solenoid as it actuates. The solenoid core pulls up on a link that rotates the armature of the contactor assembly from normal to emergency position. Each time it is pulsed, it rotates it one way, then the other way. The actual amount of time (I haven't measured it) this takes is under a second roughly. Jeff-1.0 -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
Tell him something he DOESN'T already know.
Heh, thanks Michael. What I don't know and would like to know is if my thinking with regards to ampere turns is correct. Because I CAN wind a new solenoid coil with a 1/2 pound spool of wire for about $20. Do you have good reason to believe that AWG 30 is the proper gauge, and that your calculations are correct? If so, then buy the wire and do it. If it doesn't work, you're out only $20 and the time it took to wind the coil. I don't know enough about solenoids to properly judge your calculations. But I don't see anything obviously wrong. |
Re-winding solenoids.
Jeffrey Angus wrote:
On 10/16/2011 8:12 PM, Jamie wrote: To add to that, a 1:1 control transformer of a very small size can be wired as a buck boost to operate that coil. As I mentioned previously, the solenoid requires a 5.2 amp pulse to properly actuate the contactor mechanism. With a 240/240 control transformer wired up in boost mode that would need at 1000 VA transformer as a bare minimum. Jeff-1.0 Then it must be pushing a large load a long distance. at that current, you looks like you have ~ 100 ohm coil. which means the wire in the coil is rather a large gauge since this is DC going to it. I would start around 20awg and see what the DCR 1M is on the chart. Then see if that will physically fit on the form. Jamie. |
Re-winding solenoids.
On 10/16/2011 8:44 PM, Jamie wrote:
Then it must be pushing a large load a long distance. at that current, you looks like you have ~ 100 ohm coil Did you read the details from my original posting? (Se below) which means the wire in the coil is rather a large gauge since this is DC going to it. I would start around 20awg and see what the DCR 1M is on the chart. Then see if that will physically fit on the form. I originally wrote: Coil form 1" diameter, 1-3/8" width and 1.5" depth. Going backwards on a solenoid coil java script, yields a matching 125 mH inductance (as measured) and 95 ohm DCR (as measured) for 2500 turns of #30 AWG which will fill the bobbin. This a 480 VAC actuator. roughly 100 ohms, yes. This is NOT a constant pull and hold solenoid. This is a pulsed operation. So that works out to 4.8 amps or 12,000 ampere turns. Substituting 2000 turns of #28 AWG yields 80 mH, and 42 Ohms. And subsequently roughly 12,000 ampere turns at 240 VAC. Based on: Ampere turns = (Applied voltage * number of turns)/(coil resistance) Both estimations of the needed number of turns and wire size seem correct. Putting 240 VAC across the 480 VAC coil yields only 6,000 ampere turns and obviously is NOT enough to actuate the contactor transfer mechanism. This tends to indicate that ampere turns is indeed the magic number as 6000 is not enough to actuate a mechanism that appears to require 12,000. Jeff-1.0 -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
On 10/16/2011 8:42 PM, William Sommerwerck wrote:
Do you have good reason to believe that AWG 30 is the proper gauge, and that your calculations are correct? http://www.pronine.ca/multind.htm Yields both the correct inductance and DC resistance with #30 AWG for the assumptions I've made for the physical size of the coil bobbin. If so, then buy the wire and do it. If it doesn't work, you're out only $20 and the time it took to wind the coil. I don't know enough about solenoids to properly judge your calculations. But I don't see anything obviously wrong. And that's why I thought I'd ask here. I was hoping to find someone that _is_ familiar enough to at least tell me, "Yeah, you seem to be heading in the right direction." Jeff-1.0 -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
On Oct 16, 6:59*pm, Jeffrey Angus wrote:
On 10/16/2011 8:42 PM, William Sommerwerck wrote: Do you have good reason to believe that AWG 30 is the proper gauge, and that your calculations are correct? http://www.pronine.ca/multind.htm Yields both the correct inductance and DC resistance with #30 AWG for the assumptions I've made for the physical size of the coil bobbin. If so, then buy the wire and do it. If it doesn't work, you're out only $20 and the time it took to wind the coil. I don't know enough about solenoids to properly judge your calculations. But I don't see anything obviously wrong. And that's why I thought I'd ask here. I was hoping to find someone that _is_ familiar enough to at least tell me, "Yeah, you seem to be heading in the right direction." You didn't say this solenoid was part of a transfer switch. This raises the stakes substantially. Transfer switches are used to switch the mains supply to a generator when mains power is interrupted. They serve two main purposes: to keep critical equipment functioning when mains power is interrupted, and to deenergize the power line so that workers can assume it is deenergized when they work on it. Now, the transfer switch was tested to meet specifications with the designed solenoid installed. Knowing nothing of the design or construction of the component, you propose to roll your own and stick it in. Which would be fine, if no one's life depended on its working. And if the vendor would stand behind your handicraft. I don't think Asco could reasonably foresee that someone would use a program that gives the number of turns for an air-core inductor to design a part for a life-safety application. |
Re-winding solenoids.
On Sun, 16 Oct 2011 17:30:05 -0500, Jeffrey Angus
wrote: Coil works perfectly with 480 VAC applied to the bridge recitfier. My task is to wind a new coil that will work at 240 VAC. You left that out of your initial rant. First sentence should be what the [deleted expletive] you're trying to accomplish. I did that, see the initial posting. Using DC resistance, physical size and measured inductance. What you want is an equal amount of magnetic force (i.e. gilberts) or ampere-turns for both the 480VAC and 240VAC coils. 480VAC coil = 125mH and 95 ohms XL = 2*Pi*60*125*10^-3 = 47 ohm Total impedance is the vector sum of 95 ohms and 47 ohms = Z = sqrt(95^2 + 47^2) = 105 ohms Current is: I = 480VAC / 105 ohms = 4.5A 2500 turns * 4.5A = 11,250 AT Ok, you got that part correct. Trying a different gauge for 240VAC. The hard part will be keeping the max diameter to under 1.5" OD. http://www.pronine.ca/multind.htm For #29awg, 75mH, 1990 turns, 51 ohms resistance. XL = 2*Pi*60*75*10^-3 = 28 ohm Z = sqrt(51^2 + 28^2) = 63 ohms I = 240VAC / 63 ohms = 3.8A 1990 turns * 3.8A = 7580 AT For #28awg, 60mH, 1759 turns, 37 ohms resistance. XL = 2*Pi*60*60*10^-3 = 22.5 ohm Z = sqrt(51^2 + 37^2) = 63 ohms I = 240VAC / 63 ohms = 3.8A 1759 turns * 3.8A = 6700 AT Ok, that's not going to work. Most of the impedance is coming from the DC resistance of the wire. Decreasing the gauge decreases this resistance, but also decreases the number of turns that will fit on a the spool to a maximum OD of 1.5". This isn't working. I give up for tonite. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Re-winding solenoids.
On 10/16/2011 11:08 PM, spamtrap1888 wrote:
You didn't say this solenoid was part of a transfer switch. This raises the stakes substantially. Transfer switches are used to switch the mains supply to a generator when mains power is interrupted. They serve two main purposes: to keep critical equipment functioning when mains power is interrupted, and to deenergize the power line so that workers can assume it is deenergized when they work on it. Now, the transfer switch was tested to meet specifications with the designed solenoid installed. Knowing nothing of the design or construction of the component, you propose to roll your own and stick it in. Which would be fine, if no one's life depended on its working. And if the vendor would stand behind your handicraft. I don't think Asco could reasonably foresee that someone would use a program that gives the number of turns for an air-core inductor to design a part for a life-safety application. Thank you for your information. It changes nothing. The original solenoid develops about 12,000 ampere turns at 480 Volts. The replacement needs to develop 12,000 ampere turns at 240 volts. If this were a customer, such as a extended care center where I originally bought the used generator from and replaced their original automatic transfer switch with a new compatible one I would have (and did) take proper steps to insure everything worked within the confines of a life-safety application. This is a manual transfer switch with some control logic to determine if all the power is present prior to switching. What in essence it does is not allowing you to switch to a non-existent source. I asked for an opinion that ampere turns was the right direction I was headed in to change an operating solenoid from 480 to 240 volts. I did not ask form someone such as yourself to presume that I totally lack the ethics to endanger life with a crap modification. Ya know, the way this transfer switch operates, I can just as easily add the optional "manual handle" on the side of the box to switch from normal to emergency power and throw away all the complicated stuff inside. As far as life safety is concerned, this is to handle a loss of power at the shop I operate. Simple. "The power failed." Go outside, start the generator and once it's running go back and flip the transfer switch. When the utility power returns and stays on, flip the siwtch aback and then go outside and turn the generator off. This really isn't rocket science. Jeff-1.0 -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
On 10/16/2011 11:11 PM, Jeff Liebermann wrote:
Ok, that's not going to work. Most of the impedance is coming from the DC resistance of the wire. Decreasing the gauge decreases this resistance, but also decreases the number of turns that will fit on a the spool to a maximum OD of 1.5". This isn't working. I give up for tonite. Well as long as your bitching at me for leaving something out.... The original coil is being fed through a bridge rectifier (mentioned elsewhere in the thread). So the AC impedance is less of an issue. Using the proline scripting, I came up with 80 mH using #28 AWG wire, 1988 turns and 1.54" outside diameter with 42.63 ohms. I come up with 11192 ampere turns. I've got some wiggle room to increase the bobbin size a bit. So rest well good sir, we are at a point that is "close enough" to wind up a prototype and see if works properly. If it does, then it gets potted in Epoxy to match the original physical dimensions and we call it a success. Jeff-1.0 -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
On Mon, 17 Oct 2011 02:51:21 -0500, Jeffrey Angus
wrote: On 10/16/2011 11:11 PM, Jeff Liebermann wrote: Ok, that's not going to work. Most of the impedance is coming from the DC resistance of the wire. Decreasing the gauge decreases this resistance, but also decreases the number of turns that will fit on a the spool to a maximum OD of 1.5". This isn't working. I give up for tonite. Well as long as your bitching at me for leaving something out.... I always find something to complain about. It's part of my standard usenet protocol. Nothing personal. The original coil is being fed through a bridge rectifier (mentioned elsewhere in the thread). So the AC impedance is less of an issue. Bad news. 60Hz is still AC. The AC current, is determined by the AC impedance also known as Z. Fortunately, most of it comes from the resistance of the wires, making the coil specs easier to guess. Using the proline scripting, I came up with 80 mH using #28 AWG wire, 1988 turns and 1.54" outside diameter with 42.63 ohms. You cheated by going over the OD by 0.04". Assuming you can pack the windings in as tight as the original, that shouldn't be a problem. I'm not all that confident you can do it. Use a mandrel and a slow turning lathe. I come up with 11192 ampere turns. I've got some wiggle room to increase the bobbin size a bit. So rest well good sir, we are at a point that is "close enough" to wind up a prototype and see if works properly. It will probably work. I just hate to say that as I'm sure you'll blame me when it explodes and sprays coil bobbin parts all over the shop. It might help to immolate an old solenoid on the barbeque as a burnt offering to the god of electric power for a favorable outcome. If it does, then it gets potted in Epoxy to match the original physical dimensions and we call it a success. Right. Hide the evidence. Be sure to embalm the windings in yellow Kapton (Polyimide) high temp tape before potting. I learned that the hard way after trying to pot some radios. The epoxy shrinks as it hardens, which likes to tear wires away from their attachment points. The tape provides an easy air space for the epoxy to shrink. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Re-winding solenoids.
On 10/17/2011 10:37 AM, Jeff Liebermann wrote:
I always find something to complain about. It's part of my standard usenet protocol. Nothing personal. Well of course, I've known you long enough now to fully understand the protocol. ;-) You cheated by going over the OD by 0.04". Assuming you can pack the windings in as tight as the original, that shouldn't be a problem. I'm not all that confident you can do it. Use a mandrel and a slow turning lathe. The physical demisions after the epoxy potting are 1.55, instead of my guess of 1.375), and 1.66 rather than my also guess of of 1.50. It will probably work. I just hate to say that as I'm sure you'll blame me when it explodes and sprays coil bobbin parts all over the shop. Isn't that also standard Usenet protocol? Right. Hide the evidence. Be sure to embalm the windings in yellow Kapton (Polyimide) high temp tape before potting. I still have several rolls here at the shop from when I'd rewind surplus wall warts for laughs. Jeff-1.0 the other other one. Having a vacuum pot and temperature chamber helps make stuff "right" when you do it. I kind of prefer a polyurethane for potting myself. -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
On Mon, 17 Oct 2011 11:02:42 -0500, Jeffrey Angus
wrote: Isn't that also standard Usenet protocol? Yes. The first step to analyzing a failure is to blame someone. Having a vacuum pot and temperature chamber helps make stuff "right" when you do it. I kind of prefer a polyurethane for potting myself. I like to use Bondo, because it doesn't shrink. Way back in the days when I still received a regular paycheck, the company had a "modular products" division that sold data converters into such non-critical applications like missiles and air traffic control systems. Instead of just dumping the electronics into a potting shell and filling it with epoxy, they would first fill it almost to the pour hole with sand and then top it off with epoxy. The thermal conductivity of epoxy is slightly better than lousy. The sand gives an even temperature distribution, protects against mechanical shock, and is cheaper than epoxy. It also makes post-potting repair somewhat possible. Filling the bobbin with sand before potting isn't going to do anything useful for your solenoid, but I thought I would mention it for future applications. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Re-winding solenoids.
Jeff Liebermann wrote:
On Mon, 17 Oct 2011 02:51:21 -0500, Jeffrey Angus wrote: On 10/16/2011 11:11 PM, Jeff Liebermann wrote: Ok, that's not going to work. Most of the impedance is coming from the DC resistance of the wire. Decreasing the gauge decreases this resistance, but also decreases the number of turns that will fit on a the spool to a maximum OD of 1.5". This isn't working. I give up for tonite. Well as long as your bitching at me for leaving something out.... I always find something to complain about. It's part of my standard usenet protocol. Nothing personal. The original coil is being fed through a bridge rectifier (mentioned elsewhere in the thread). So the AC impedance is less of an issue. Bad news. 60Hz is still AC. The AC current, is determined by the AC impedance also known as Z. Fortunately, most of it comes from the resistance of the wires, making the coil specs easier to guess. Using the proline scripting, I came up with 80 mH using #28 AWG wire, 1988 turns and 1.54" outside diameter with 42.63 ohms. You cheated by going over the OD by 0.04". Assuming you can pack the windings in as tight as the original, that shouldn't be a problem. I'm not all that confident you can do it. Use a mandrel and a slow turning lathe. I come up with 11192 ampere turns. I've got some wiggle room to increase the bobbin size a bit. So rest well good sir, we are at a point that is "close enough" to wind up a prototype and see if works properly. It will probably work. I just hate to say that as I'm sure you'll blame me when it explodes and sprays coil bobbin parts all over the shop. It might help to immolate an old solenoid on the barbeque as a burnt offering to the god of electric power for a favorable outcome. If it does, then it gets potted in Epoxy to match the original physical dimensions and we call it a success. Right. Hide the evidence. Be sure to embalm the windings in yellow Kapton (Polyimide) high temp tape before potting. I learned that the hard way after trying to pot some radios. The epoxy shrinks as it hardens, which likes to tear wires away from their attachment points. The tape provides an easy air space for the epoxy to shrink. You said in an earlier post that the current in the coil needs to be around 5 amps, and you propose to use 28 AWG wire to wind it. AWG 28 wire has a rated ampacity for chassis wiring (inside a bundle, similar to your solenoid coil), is only 1.4 amps. I doubt that your coil would last very long with that amount of current. More investigation is necessary. Might be less painful to spring for the proper solenoid from the manufacturer. -- David dgminala at mediacombb dot net |
Re-winding solenoids.
Dave M wrote:
Jeff Liebermann wrote: On Mon, 17 Oct 2011 02:51:21 -0500, Jeffrey Angus wrote: On 10/16/2011 11:11 PM, Jeff Liebermann wrote: Ok, that's not going to work. Most of the impedance is coming from the DC resistance of the wire. Decreasing the gauge decreases this resistance, but also decreases the number of turns that will fit on a the spool to a maximum OD of 1.5". This isn't working. I give up for tonite. Well as long as your bitching at me for leaving something out.... I always find something to complain about. It's part of my standard usenet protocol. Nothing personal. The original coil is being fed through a bridge rectifier (mentioned elsewhere in the thread). So the AC impedance is less of an issue. Bad news. 60Hz is still AC. The AC current, is determined by the AC impedance also known as Z. Fortunately, most of it comes from the resistance of the wires, making the coil specs easier to guess. Using the proline scripting, I came up with 80 mH using #28 AWG wire, 1988 turns and 1.54" outside diameter with 42.63 ohms. You cheated by going over the OD by 0.04". Assuming you can pack the windings in as tight as the original, that shouldn't be a problem. I'm not all that confident you can do it. Use a mandrel and a slow turning lathe. I come up with 11192 ampere turns. I've got some wiggle room to increase the bobbin size a bit. So rest well good sir, we are at a point that is "close enough" to wind up a prototype and see if works properly. It will probably work. I just hate to say that as I'm sure you'll blame me when it explodes and sprays coil bobbin parts all over the shop. It might help to immolate an old solenoid on the barbeque as a burnt offering to the god of electric power for a favorable outcome. If it does, then it gets potted in Epoxy to match the original physical dimensions and we call it a success. Right. Hide the evidence. Be sure to embalm the windings in yellow Kapton (Polyimide) high temp tape before potting. I learned that the hard way after trying to pot some radios. The epoxy shrinks as it hardens, which likes to tear wires away from their attachment points. The tape provides an easy air space for the epoxy to shrink. You said in an earlier post that the current in the coil needs to be around 5 amps, and you propose to use 28 AWG wire to wind it. AWG 28 wire has a rated ampacity for chassis wiring (inside a bundle, similar to your solenoid coil), is only 1.4 amps. I doubt that your coil would last very long with that amount of current. More investigation is necessary. Might be less painful to spring for the proper solenoid from the manufacturer. OOps.. I got that wrong.. That figure was the capacity in free air... The capacity of AWG28 wire in an enclosed space is 0.83 amps. -- David dgminala at mediacombb dot net |
Re-winding solenoids.
On 10/17/2011 2:21 PM, Dave M wrote:
You said in an earlier post that the current in the coil needs to be around 5 amps, and you propose to use 28 AWG wire to wind it. AWG 28 wire has a rated ampacity for chassis wiring (inside a bundle, similar to your solenoid coil), is only 1.4 amps. I doubt that your coil would last very long with that amount of current. More investigation is necessary. Might be less painful to spring for the proper solenoid from the manufacturer. OOps.. I got that wrong.. That figure was the capacity in free air... The capacity of AWG28 wire in an enclosed space is 0.83 amps. I'm sure that it is. The original coil at 480 volts draws 5.2 amps and is wounnd with #30 AWG. Guess I need to repeat this. It is PULSED not STEADY operation. Jeff-1.0 -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
Jeffrey Angus wrote:
On 10/16/2011 11:11 PM, Jeff Liebermann wrote: Ok, that's not going to work. Most of the impedance is coming from the DC resistance of the wire. Decreasing the gauge decreases this resistance, but also decreases the number of turns that will fit on a the spool to a maximum OD of 1.5". This isn't working. I give up for tonite. Well as long as your bitching at me for leaving something out.... The original coil is being fed through a bridge rectifier (mentioned elsewhere in the thread). So the AC impedance is less of an issue. Using the proline scripting, I came up with 80 mH using #28 AWG wire, 1988 turns and 1.54" outside diameter with 42.63 ohms. I come up with 11192 ampere turns. I've got some wiggle room to increase the bobbin size a bit. So rest well good sir, we are at a point that is "close enough" to wind up a prototype and see if works properly. If it does, then it gets potted in Epoxy to match the original physical dimensions and we call it a success. Jeff-1.0 You know, at this point, you pretty much don't care I would assume how ever, have you thought about constructing a voltage double rectifier instead of that bridge rectifier to drive that coil? +-------+-------++ | | | + | | D1 - | | ^ | | | | + C1 + + C| 240 AC in | --- C| 480 Solenoid || | ---C2 C| +---+-||+------+ + | || + | + | | | - | | D2 ^ | | 240 AC in + | | | + | +-------------+-------++-------+ (created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de) I suppose if you had to motor caps around you could use those, the large ones of course. What ever. Jamie |
Re-winding solenoids.
On Mon, 17 Oct 2011 19:05:15 -0400, Jamie
t wrote: You know, at this point, you pretty much don't care I would assume how ever, have you thought about constructing a voltage double rectifier instead of that bridge rectifier to drive that coil? +-------+-------++ | | | + | | D1 - | | ^ | | | | + C1 + + C| 240 AC in | --- C| 480 Solenoid || | ---C2 C| +---+-||+------+ + | || + | + | | | - | | D2 ^ | | 240 AC in + | | | + | +-------------+-------++-------+ (created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de) I suppose if you had to motor caps around you could use those, the large ones of course. What ever. Jamie Good idea. The caps will need to be charged by the 240VAC line voltage in a few cycles in order to get any kind of usable response time for pulsed operation. That means the caps are going to be rather big. A rough guess would be: AC impedance of the coil is roughly: 480VAC / 5A = 96 ohms To get C2 up to about 90% of full charge in 2 cycles, the capacitive reactance of C1 would need to be about: Xc = 96 * 0.1 = 9.6 ohms At 60Hz, that's 276 uF. 330uf 600VDC caps should work. I'm not very confident with my crude approximations. Therefore, I would feed the model to LTSpice and see what it's really going to do. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Re-winding solenoids.
On 10/18/2011 11:47 AM, Jeff Liebermann wrote:
At 60Hz, that's 276 uF. 330uf 600VDC caps should work. I'm not very confident with my crude approximations. Therefore, I would feed the model to LTSpice and see what it's really going to do. You're charging to the peak values, not RMS, so it's going to be 680 volts at a minimum, and probably more like 750 for some margin of safety. Caps of that size and rating will end up costing as much as the coil itself. Jeff -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
On 10/17/2011 6:05 PM, Jamie wrote:
You know, at this point, you pretty much don't care You're right. I don't. Because my original question was in regards to ampere turns and rewinding a solenoid for a different operating voltage. Because so far, with one notable exception, everyone has insisted on coming up with some Rube Goldberg solution or accusing me of trying to murder widows and orphans. Jeff-1.0 -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
On Oct 19, 5:09*am, Jeffrey Angus wrote:
On 10/17/2011 6:05 PM, Jamie wrote: You know, at this point, you pretty much don't care You're right. I don't. Because my original question was in regards to ampere turns and rewinding a solenoid for a different operating voltage. I wish that that had been your original question, which was a rambling stream of consciousness. Your reference to a program for calculating aircore inductors made me think you were using "solenoid" in the sense of "helical coil." Because so far, with one notable exception, everyone has insisted on coming up with some Rube Goldberg solution or accusing me of trying to murder widows and orphans. Your desire to save $380 in the belief that ASCO was screwing its customers with jacked-up prices seemed a bit unreasonable, the more so when you revealed the true application for the solenoid actuator. But your juryrig would merely produce widows and orphans, not kill them. Only the lineman trying to restore power would be killed if your Rube Goldberg solution failed to work. |
Re-winding solenoids.
spamtrap1888 wrote: Your desire to save $380 in the belief that ASCO was screwing its customers with jacked-up prices seemed a bit unreasonable, the more so when you revealed the true application for the solenoid actuator. But your juryrig would merely produce widows and orphans, not kill them. Only the lineman trying to restore power would be killed if your Rube Goldberg solution failed to work. Can't follow a thread, can you? It's for his workshop. -- You can't have a sense of humor, if you have no sense. |
Re-winding solenoids.
On 10/19/2011 10:52 AM, spamtrap1888 wrote:
But your juryrig would merely produce widows and orphans, not kill them. Only the lineman trying to restore power would be killed if your Rube Goldberg solution failed to work. Since you seem to be so good at divination....Pray tell me just exactly how a three-pole double throw transfer switch can connect the emergency power to the line rather than the load. The ONLY thing this switch can do if the solenoid fails is to NOT actuate the switch from one position the other. But I'm sure you have a reasonable explanation on how that can not be the case here. Jeff-1.0 -- "Everything from Crackers to Coffins" |
Re-winding solenoids.
spamtrap1888 wrote:
On Oct 19, 5:09 am, Jeffrey Angus wrote: On 10/17/2011 6:05 PM, Jamie wrote: You know, at this point, you pretty much don't care You're right. I don't. Because my original question was in regards to ampere turns and rewinding a solenoid for a different operating voltage. I wish that that had been your original question, which was a rambling stream of consciousness. Your reference to a program for calculating aircore inductors made me think you were using "solenoid" in the sense of "helical coil." Because so far, with one notable exception, everyone has insisted on coming up with some Rube Goldberg solution or accusing me of trying to murder widows and orphans. Your desire to save $380 in the belief that ASCO was screwing its customers with jacked-up prices seemed a bit unreasonable, the more so when you revealed the true application for the solenoid actuator. But your juryrig would merely produce widows and orphans, not kill them. Only the lineman trying to restore power would be killed if your Rube Goldberg solution failed to work. I must say, you are an idiot! How is the device itself any less dangerous than using an alternate to operate it? Jamie |
Re-winding solenoids.
On Oct 19, 2:47*pm, Jeffrey Angus wrote:
On 10/19/2011 10:52 AM, spamtrap1888 wrote: But your juryrig would merely produce widows and orphans, not kill them. Only the lineman trying to restore power would be killed if your Rube Goldberg solution failed to work. Since you seem to be so good at divination....Pray tell me just exactly how a three-pole double throw transfer switch can connect the emergency power to the line rather than the load. The ONLY thing this switch can do if the solenoid fails is to NOT actuate the switch from one position the other. But I'm sure you have a reasonable explanation on how that can not be the case here. I see that only the ASCO 4000 and 7000 series are closed-transition switches, i.e. break before make, not the Series 940 -- which I had to look up from the replacement part number you gave. My bad, I suppose. |
Re-winding solenoids.
On Oct 19, 3:14*pm, Jamie
t wrote: spamtrap1888 wrote: On Oct 19, 5:09 am, Jeffrey Angus wrote: On 10/17/2011 6:05 PM, Jamie wrote: You know, at this point, you pretty much don't care You're right. I don't. Because my original question was in regards to ampere turns and rewinding a solenoid for a different operating voltage. I wish that that had been your original question, which was a rambling stream of consciousness. Your reference to a program for calculating aircore inductors made me think you were using "solenoid" in the sense of "helical coil." Because so far, with one notable exception, everyone has insisted on coming up with some Rube Goldberg solution or accusing me of trying to murder widows and orphans. Your desire to save $380 in the belief that ASCO was screwing its customers with jacked-up prices seemed a bit unreasonable, the more so when you revealed the true application for the solenoid actuator. But your juryrig would merely produce widows and orphans, not kill them. Only the lineman trying to restore power would be killed if your Rube Goldberg solution failed to work. I must say, you are an idiot! * How is the device itself any less dangerous than using an alternate to operate it? Jamie If the alternate does not operate sufficiently like the original. If he could explain how the actuator works and what the important parameters were, we could speculate as to all the possible failure modes. |
Re-winding solenoids.
spamtrap1888 wrote:
On Oct 19, 3:14 pm, Jamie t wrote: spamtrap1888 wrote: On Oct 19, 5:09 am, Jeffrey Angus wrote: On 10/17/2011 6:05 PM, Jamie wrote: You know, at this point, you pretty much don't care You're right. I don't. Because my original question was in regards to ampere turns and rewinding a solenoid for a different operating voltage. I wish that that had been your original question, which was a rambling stream of consciousness. Your reference to a program for calculating aircore inductors made me think you were using "solenoid" in the sense of "helical coil." Because so far, with one notable exception, everyone has insisted on coming up with some Rube Goldberg solution or accusing me of trying to murder widows and orphans. Your desire to save $380 in the belief that ASCO was screwing its customers with jacked-up prices seemed a bit unreasonable, the more so when you revealed the true application for the solenoid actuator. But your juryrig would merely produce widows and orphans, not kill them. Only the lineman trying to restore power would be killed if your Rube Goldberg solution failed to work. I must say, you are an idiot! How is the device itself any less dangerous than using an alternate to operate it? Jamie If the alternate does not operate sufficiently like the original. If he could explain how the actuator works and what the important parameters were, we could speculate as to all the possible failure modes. You can speculate all you want. You sound like an attorney looking for work or closely related to one. If you read the blog, you would see what he is using if for, and if he really wants you to know, I am sure he'll refresh your memory. Jamie |
Re-winding solenoids.
On 10/19/2011 8:39 PM, spamtrap1888 wrote:
I see that only the ASCO 4000 and 7000 series are closed-transition switches, i.e. break before make, not the Series 940 -- which I had to look up from the replacement part number you gave. My bad, I suppose. I suppose. The solenoid coil listed is for the series 940. It is also used for several other series. Specifically, in my case, the Series 386 manual transfer switch. And in case you missed it earlier, here is the link for an eBay auction showing picturs of the transfer switch contactor. A similar model. 2-pole 120 VAC rather than 3-pole 480 VAC. http://www.ebay.com/itm/130520617745 And if you go to the partsasco.com website and look up the replacement part numbers for the model 300 or 386, it directs you to the coil marked as being for the series 940. This is the coil itself from ASCO. http://www.ascoparts.com/343500-063.html But again, you're making all sorts of asumption looking to find fault. You've done nothing what so ever to answer the question on rewinding a solenoid to operate at 240 volts rather than 480. Jeff-1.0 -- "Everything from Crackers to Coffins" |
| All times are GMT +1. The time now is 10:46 AM. |
|
Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 DIYbanter