On 1/18/2019 3:07 PM, Phil Allison wrote:> Bob Engelhardt wrote: > >> >> MOTs are commonly 1500VA> ** No they are not. > > Continuous fan cooling plus *intermittent operation* allows the use of an otherwise grossly undersized transformer.I'm sticking with the functional definition: if it's used at 1500VA, then it is a 1500VA transformer.>> & I'm using my repurposed one at 400VA max,> ** IOW, right on the limit with no fan and continuous loaded.I didn't say that there was no fan and it isn't continuously loaded - more intermittently than in an oven.> So the tranny draws a heavy magnetising current & runs hot off load.So what? It's been working perfectly for 10 years. How would it work better if I had gone to the trouble of scoping the primary current and adding turns? Running cooler doesn't count as "working better".
Make your own Power Transformer
Started by ●January 13, 2019
Reply by ●January 19, 20192019-01-19
Reply by ●January 19, 20192019-01-19
Bob Engelhardt wrote:> On 1/18/2019 3:07 PM, Phil Allison wrote: > > Bob Engelhardt wrote: > > > >> > >> MOTs are commonly 1500VA > > > ** No they are not. > > > > Continuous fan cooling plus *intermittent operation* allows the use > > of an otherwise grossly undersized transformer. > > > I'm sticking with the functional definition: if it's used at 1500VA, > then it is a 1500VA transformer. >**> > >> & I'm using my repurposed one at 400VA max, > > > ** IOW, right on the limit with no fan and continuous loaded. > > I didn't say that there was no fan and it isn't continuously loaded - > more intermittently than in an oven. >** 400VA would be the limit under the conditions as stated. What you failed to mention is your problem.> > So the tranny draws a heavy magnetising current & runs hot off load. > > So what?** It needed mentioning.> It's been working perfectly for 10 years.** Aside from humming and running hot all the time....> How would it work > better if I had gone to the trouble of scoping the primary current and > adding turns?** No mention of "scoping" came from me.> Running cooler doesn't count as "working better".** Does in most folk's book. I can see you are made from different stuff. ..... Phil
Reply by ●January 21, 20192019-01-21
On Friday, January 18, 2019 at 12:32:30 PM UTC-8, George Herold wrote:> Magnetostriction in the iron? Hum should be at 100/120 Hz and not 50/60.With a resistive load, yes; with a rectifying load, could be either or both.
Reply by ●January 21, 20192019-01-21
On Monday, 21 January 2019 07:28:15 UTC, whit3rd wrote:> On Friday, January 18, 2019 at 12:32:30 PM UTC-8, George Herold wrote:> > Magnetostriction in the iron? Hum should be at 100/120 Hz and not 50/60. > > With a resistive load, yes; with a rectifying load, could be either or both.could also be much higher with nonlinearity. NT
Reply by ●January 28, 20192019-01-28
On Sun, 13 Jan 2019 20:03:16 -0600, tubeguy@myshop.com wrote:>Apparently he bought that bobbin, and the laminations to fit it. Is >there a place that sells that sells the parts (bobbin and laminations)?These days, the bobbin could possibly be 3D-printed? -- RoRo
Reply by ●January 29, 20192019-01-29
On 1/28/19 4:47 PM, Robert Roland wrote:> On Sun, 13 Jan 2019 20:03:16 -0600, tubeguy@myshop.com wrote: > >> Apparently he bought that bobbin, and the laminations to fit it. Is >> there a place that sells that sells the parts (bobbin and laminations)? > > These days, the bobbin could possibly be 3D-printed? >If you don't mind it melting. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
Reply by ●January 29, 20192019-01-29
"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message news:o92dnbihka_mB83BnZ2dnUU7-WGdnZ2d@supernews.com...>> These days, the bobbin could possibly be 3D-printed? >> > > If you don't mind it melting. >Not so -- I might not be inclined to trust an extruder product, at least not without a much fancier material than ABS or PLA (and in which case, you may need a special extruder head to handle the much higher temp, and possibly the abrasiveness if it's glass fiber reinforced). There are some pretty fantastic materials available in UV-cure resin, though! Just a matter of how much you're willing to pay for it, and how much you'll be able to use within its shelf life... Tim -- Seven Transistor Labs, LLC Electrical Engineering Consultation and Design Website: https://www.seventransistorlabs.com/
Reply by ●January 29, 20192019-01-29
On 1/29/19 3:21 PM, Tim Williams wrote:> "Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message > news:o92dnbihka_mB83BnZ2dnUU7-WGdnZ2d@supernews.com... >>> These days, the bobbin could possibly be 3D-printed? >>> >> >> If you don't mind it melting. >> > > Not so -- I might not be inclined to trust an extruder product, at least > not without a much fancier material than ABS or PLA (and in which case, > you may need a special extruder head to handle the much higher temp, and > possibly the abrasiveness if it's glass fiber reinforced). > > There are some pretty fantastic materials available in UV-cure resin, > though!� Just a matter of how much you're willing to pay for it, and how > much you'll be able to use within its shelf life... > > Tim >Yeah, but you need a UV laser system to cure it. It would probably be cheaper to machine it from solid yourself than to get it printed. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●January 29, 20192019-01-29
On 1/29/2019 2:24 PM, Phil Hobbs wrote:> On 1/29/19 3:21 PM, Tim Williams wrote: >> "Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message >> news:o92dnbihka_mB83BnZ2dnUU7-WGdnZ2d@supernews.com... >>>> These days, the bobbin could possibly be 3D-printed? >>>> >>> >>> If you don't mind it melting. >>> >> >> Not so -- I might not be inclined to trust an extruder product, at >> least not without a much fancier material than ABS or PLA (and in >> which case, you may need a special extruder head to handle the much >> higher temp, and possibly the abrasiveness if it's glass fiber >> reinforced). >> >> There are some pretty fantastic materials available in UV-cure resin, >> though!� Just a matter of how much you're willing to pay for it, and >> how much you'll be able to use within its shelf life... >> >> Tim >> > > Yeah, but you need a UV laser system to cure it.� It would probably be > cheaper to machine it from solid yourself than to get it printed. > > Cheers > > Phil Hobbs >Go to a motor rewind shop and ask for the paper they use to insulate the wire when they put it in the slot. It' not paper actually and will withstand high temperatures. Then use their high temp tape to put together a bobbin. Mikek
Reply by ●January 30, 20192019-01-30
On Sunday, 13 January 2019 21:03:23 UTC-5, tub...@myshop.com wrote:> I watched a youtube video of a guy winding his own power transformer. He > used a pre-made plastic bobbin, wound the enameled wire as needed, and > put in the steel laminations. > > Apparently he bought that bobbin, and the laminations to fit it. Is > there a place that sells that sells the parts (bobbin and laminations)?Improvise? https://www.mx6.com/forums/lounge/196292-third-world-arc-welding.html --Spehro Pefhany
