Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
Search
"Yellow Box Coater"
|
Aurigema, Andrew N. (KSC)[ASRC AEROSPACE]
开云体育I would think James Lerch would.? Did you try to
contach James................. he is playing toy helocopters these days but
should be monitoring this list.?
?
Drew? in soggy Fla ( opposite side of the state from
James ) From: VacuumX@... [mailto:VacuumX@...] On Behalf Of glinos7124 Sent: Thursday, June 19, 2008 6:22 PM To: VacuumX@... Subject: [VacuumX] "Yellow Box Coater"
|
|
--- In VacuumX@..., "glinos7124" <tg@...> wrote:
I think he's using a single 4" diffusion pump and two fore pumps. There is info on his first system that had a smaller chamber on his Web site at He's using Invoil 20 in both diff. and fore pumps with freon cooled cold trap just undwer the chamber. Cool stuff!! Roy M. |
|
--- In VacuumX@..., "glinos7124" <tg@...> wrote:
By they way I'm working on a similar project. I have almost everything and I'm hooking up power for my new TIG welder so I can assemble some of the parts. I have purchased most of the parts from eBay and the rest came from the local Menards, a surplus metal supplier and some dumpster diving. I'm currently on the tail end of cleaning my ancient NRC 4" diff. pump. Looks like somebody let it overheat and part of the aluminum splash shield was fused to the bottom of the pump. For my initial chamber I have sectioned a 12" compressor tank and purchased an angle flange from McMaster Carr to use in forming the sealing surface at the open end. I have a small welder that I'm planning on using to power the evap. coils and will controll it with a Variac. Roy M. |
|
Aurigema, Andrew N. (KSC)[ASRC AEROSPACE]
开云体育Get a big variac for that.? I burned up a 1kw unit
discovering that they are not rated to what they say they can take.? go
twice what you think you need.???You know you need a serious
stepdown transformer to make lots of amps at low voltage ( like 30 amps at 3 vac
for each emmitter ).??
?
I just chatted with James a few minutes ago so I know
he?is at least typing.? He may not be monitoring?this list right
now.? ??
?
Andrew in sunny FLA
?
? From: VacuumX@... [mailto:VacuumX@...] On Behalf Of radroy92 Sent: Monday, June 30, 2008 12:53 PM To: VacuumX@... Subject: [VacuumX] Re: "Yellow Box Coater" --- In VacuumX@yahoogroups
> > > Does anyone have any details on the Lerch/Jones box coater > at the St. Petersburg Mirror Lab? > > Dimensions, materials, pumps, sensors,.... that kind of thing. > > I'm mulling over building one. > It looks like a challenging, but doable project. > > tom > By they way I'm working on a similar project. I have almost everything and I'm hooking up power for my new TIG welder so I can assemble some of the parts. I have purchased most of the parts from eBay and the rest came from the local Menards, a surplus metal supplier and some dumpster diving. I'm currently on the tail end of cleaning my ancient NRC 4" diff. pump. Looks like somebody let it overheat and part of the aluminum splash shield was fused to the bottom of the pump. For my initial chamber I have sectioned a 12" compressor tank and purchased an angle flange from McMaster Carr to use in forming the sealing surface at the open end. I have a small welder that I'm planning on using to power the evap. coils and will controll it with a Variac. Roy M. |
|
Why do we have to use heavy emmitters like that can we use thinner
wire? Or does it fall apart at those temperatures? Roy M. --- In VacuumX@..., "Aurigema, Andrew N. (KSC)[ASRC AEROSPACE]" <andrew.n.aurigema@...> wrote: they are not rated to what they say they can take. go twice what youthink you need. You know you need a serious stepdown transformer to makeemmitter ). Behalf Of radroy92everything and I'm hooking up power for my new TIG welder so I can assemblesome of the parts. I have purchased most of the parts from eBay and therest came from the local Menards, a surplus metal supplier and somedumpster diving. I'm currently on the tail end of cleaning my ancient NRC 4"purchased an angle flange from McMaster Carr to use in forming the sealingsurface at the open end. I have a small welder that I'm planning on usingto power the evap. coils and will controll it with a Variac. |
|
Aurigema, Andrew N. (KSC)[ASRC AEROSPACE]
开云体育You can use single wire emmitters.? James does.?
his emmitters are about 1mm diameter bent into a U shape.? I bought the
tri-wire ones that are pre twisted so i could put more aluminum on each
strand.? I only have 24 emmitters and have to cover a 60" diameter disk so
I needed to put out some serious material.??You cant put to much
aluminunm on each wire or the tungston disolves into the aluminum and?you
eat up the wires.? So I put?3 wires on each emmitter with three little
strips of aluminum ( about 60 mg total ) and zap it with lots of
current.??
?
Andrew? From: VacuumX@... [mailto:VacuumX@...] On Behalf Of radroy92 Sent: Tuesday, July 01, 2008 2:07 PM To: VacuumX@... Subject: [VacuumX] Re: "Yellow Box Coater" Why do we have to use heavy emmitters like that can we use thinner --- In VacuumX@yahoogroups AEROSPACE]" ...> wrote: > > Get a big variac for that. I burned up a 1kw unit discovering that they > are not rated to what they say they can take. go twice what you think > you need. You know you need a serious stepdown transformer to make > lots of amps at low voltage ( like 30 amps at 3 vac for each emmitter ). > > > I just chatted with James a few minutes ago so I know he is at least > typing. He may not be monitoring this list right now. > > Andrew in sunny FLA > > > > ____________ > > From: VacuumX@yahoogroups Behalf > Of radroy92 > Sent: Monday, June 30, 2008 12:53 PM > To: VacuumX@yahoogroups > Subject: [VacuumX] Re: "Yellow Box Coater" > > > > --- In VacuumX@yahoogroups > "glinos7124" wrote: > > > > > > Does anyone have any details on the Lerch/Jones box coater > > at the St. Petersburg Mirror Lab? > > > > Dimensions, materials, pumps, sensors,.... that kind of thing. > > > > I'm mulling over building one. > > It looks like a challenging, but doable project. > > > > tom > > > > By they way I'm working on a similar project. I have almost everything > and I'm hooking up power for my new TIG welder so I can assemble some > of the parts. I have purchased most of the parts from eBay and the rest > came from the local Menards, a surplus metal supplier and some dumpster > diving. I'm currently on the tail end of cleaning my ancient NRC 4" > diff. pump. Looks like somebody let it overheat and part of the > aluminum splash shield was fused to the bottom of the pump. For my > initial chamber I have sectioned a 12" compressor tank and purchased an > angle flange from McMaster Carr to use in forming the sealing surface > at the open end. I have a small welder that I'm planning on using to > power the evap. coils and will controll it with a Variac. > > Roy M. > |
|
How many emitters would I need for a 12.5 mirror??
I checked my litle welder I'm planning on using for a supply for the emmitters. My Variac was putting out 13 Amps at 120 Volts. The welder was putting out 30 Amps at 30 Volts. This was with a 3.5 " long coil of 3/32 stainless wire that measured 1.1 ohm. It was glowing yellow hot laying on the concrete. Any more and it would melt. It fused to the concrete and a few spots. Roy M. --- In VacuumX@..., "Aurigema, Andrew N. (KSC)[ASRC AEROSPACE]" <andrew.n.aurigema@...> wrote: about 1mm diameter bent into a U shape. I bought the tri-wire ones thatare pre twisted so i could put more aluminum on each strand. I onlyhave 24 emmitters and have to cover a 60" diameter disk so I needed to putout some serious material. You cant put to much aluminunm on each wireor the tungston disolves into the aluminum and you eat up the wires.So I put 3 wires on each emmitter with three little strips of aluminum (Behalf Of radroy92that theyleastare not rated to what they say they can take. go twice what youthinkyou need. You know you need a serious stepdown transformer to makeemmitter ). 40yahoogroups.com> ] Ontyping. He may not be monitoring this list right now.[mailto:VacuumX@... <mailto:VacuumX% BehalftheOf radroy92<mailto:VacuumX%40yahoogroups.com> , rest4"came from the local Menards, a surplus metal supplier and somedumpsterdiving. I'm currently on the tail end of cleaning my ancient NRC mydiff. pump. Looks like somebody let it overheat and part of the initial chamber I have sectioned a 12" compressor tank andpurchased anangle flange from McMaster Carr to use in forming the sealingsurfaceat the open end. I have a small welder that I'm planning on usingtopower the evap. coils and will controll it with a Variac. |
|
Aurigema, Andrew N. (KSC)[ASRC AEROSPACE]
开云体育That is what is going to take you a lot of time to figure
out.? You can use a lot of emmitters ( 18 or so ) close up ( a few inches
away? )? or a lesser number farther back.? In theory you could
put one at the focal point of the mirror and it would give you the best overall
coating.? But you will need a long chamber with very very good vacuum for
that.?
?
Not sure how you are using a variac and welder at the same
time.?
?
I use my 2.5kva variac to power a 120 : 24 vac x 1500 watts
stepdown transformer.? the 24 vac is just right to power 4 tungstens in
series.? It took me a lot of experimentation to get the right number of
emmitters in series and parallel?for my power supplies.? Now I can
start?out cherry red to wick the aluminum onto the tungsten?then go to
near white hot for a few seconds then back to cherry and then off.? If you
hit the power to fast the aluminum?just melts and falls.? that is very
very very bad?for you mirror so dont?ever let that happen.?
??
?
Andrew From: VacuumX@... [mailto:VacuumX@...] On Behalf Of radroy92 Sent: Tuesday, July 01, 2008 5:36 PM To: VacuumX@... Subject: [VacuumX] Re: "Yellow Box Coater" How many emitters would I need for a 12.5 mirror?? --- In VacuumX@yahoogroups AEROSPACE]" ...> wrote: > > You can use single wire emmitters. James does. his emmitters are about > 1mm diameter bent into a U shape. I bought the tri-wire ones that are > pre twisted so i could put more aluminum on each strand. I only have 24 > emmitters and have to cover a 60" diameter disk so I needed to put out > some serious material. You cant put to much aluminunm on each wire or > the tungston disolves into the aluminum and you eat up the wires. So I > put 3 wires on each emmitter with three little strips of aluminum ( > about 60 mg total ) and zap it with lots of current. > > Andrew > > ____________ > > From: VacuumX@yahoogroups Behalf > Of radroy92 > Sent: Tuesday, July 01, 2008 2:07 PM > To: VacuumX@yahoogroups > Subject: [VacuumX] Re: "Yellow Box Coater" > > > > Why do we have to use heavy emmitters like that can we use thinner > wire? Or does it fall apart at those temperatures? > > Roy M. > > --- In VacuumX@yahoogroups > "Aurigema, Andrew N. (KSC)[ASRC > AEROSPACE]" > wrote: > > > > Get a big variac for that. I burned up a 1kw unit discovering that > they > > are not rated to what they say they can take. go twice what you > think > > you need. You know you need a serious stepdown transformer to make > > lots of amps at low voltage ( like 30 amps at 3 vac for each > emmitter ). > > > > > > I just chatted with James a few minutes ago so I know he is at least > > typing. He may not be monitoring this list right now. > > > > Andrew in sunny FLA > > > > > > > > ____________ > > > > From: VacuumX@yahoogroups > [mailto:VacuumX@yahoogroups > Behalf > > Of radroy92 > > Sent: Monday, June 30, 2008 12:53 PM > > To: VacuumX@yahoogroups > > Subject: [VacuumX] Re: "Yellow Box Coater" > > > > > > > > --- In VacuumX@yahoogroups > 40yahoogroups. > > "glinos7124" wrote: > > > > > > > > > Does anyone have any details on the Lerch/Jones box coater > > > at the St. Petersburg Mirror Lab? > > > > > > Dimensions, materials, pumps, sensors,.... that kind of thing. > > > > > > I'm mulling over building one. > > > It looks like a challenging, but doable project. > > > > > > tom > > > > > > > By they way I'm working on a similar project. I have almost > everything > > and I'm hooking up power for my new TIG welder so I can assemble > some > > of the parts. I have purchased most of the parts from eBay and the > rest > > came from the local Menards, a surplus metal supplier and some > dumpster > > diving. I'm currently on the tail end of cleaning my ancient NRC 4" > > diff. pump. Looks like somebody let it overheat and part of the > > aluminum splash shield was fused to the bottom of the pump. For my > > initial chamber I have sectioned a 12" compressor tank and > purchased an > > angle flange from McMaster Carr to use in forming the sealing > surface > > at the open end. I have a small welder that I'm planning on using > to > > power the evap. coils and will controll it with a Variac. > > > > Roy M. > > > |
|
Hi Andrew,
The welder I want to use is a little Sears carbon arc/stick welder with a max output of 50 Amps at 45 volts or so. It runs on 120 Volts so I just plugged it into a 10 Amp Variac. Can Nichrome wire be used for emitters?? Roy M. --- In VacuumX@..., "Aurigema, Andrew N. (KSC)[ASRC AEROSPACE]" <andrew.n.aurigema@...> wrote: can use a lot of emmitters ( 18 or so ) close up ( a few inchesaway ) or a lesser number farther back. In theory you could put one at thefocal point of the mirror and it would give you the best overallcoating. But you will need a long chamber with very very good vacuum for that.series. It took me a lot of experimentation to get the right number ofemmitters in series and parallel for my power supplies. Now I can start outwhite hot for a few seconds then back to cherry and then off. If you hitthe power to fast the aluminum just melts and falls. that is very veryvery bad for you mirror so dont ever let that happen.Behalf Of radroy92the emmitters. My Variac was putting out 13 Amps at 120 Volts. Theput outwiresome serious material. You cant put to much aluminunm on each or(the tungston disolves into the aluminum and you eat up the wires.So Iput 3 wires on each emmitter with three little strips of aluminum 40yahoogroups.com> ] Onabout 60 mg total ) and zap it with lots of current.[mailto:VacuumX@... <mailto:VacuumX% BehalfthinnerOf radroy92 makewire? Or does it fall apart at those temperatures?<mailto:VacuumX%40yahoogroups.com> , 40yahoogroups.com>leastlots of amps at low voltage ( like 30 amps at 3 vac for eachemmitter ). <mailto:VacuumX%40yahoogroups.com>assemble<mailto:VacuumX%40yahoogroups.com> ,"glinos7124" <tg@> wrote:everythingBy they way I'm working on a similar project. I have almost NRCsometheof the parts. I have purchased most of the parts from eBay andrestcame from the local Menards, a surplus metal supplier and somedumpsterdiving. I'm currently on the tail end of cleaning my ancient 4"usingmydiff. pump. Looks like somebody let it overheat and part of the topower the evap. coils and will controll it with a Variac. |
|
Aurigema, Andrew N. (KSC)[ASRC AEROSPACE]
开云体育I dont think you can use nicchrome wire.? check out
Midwestern Tungsten's orphin bin?or go to JK Leskers and look at all the
stuff they have.? The catalog is a serious source of info.?
?
Your welder is going to try to put out around 2kva.?
Is your variac rated for 4kva ???? It better be or it will simply
smoke.??Variac do not like max amp draw for very long......... they
get hot and the insulation on the winding
breaksdown.??
?
? From: VacuumX@... [mailto:VacuumX@...] On Behalf Of radroy92 Sent: Wednesday, July 02, 2008 4:18 PM To: VacuumX@... Subject: [VacuumX] Re: "Yellow Box Coater" Hi Andrew, --- In VacuumX@yahoogroups AEROSPACE]" ...> wrote: > > That is what is going to take you a lot of time to figure out. You can > use a lot of emmitters ( 18 or so ) close up ( a few inches away ) or > a lesser number farther back. In theory you could put one at the focal > point of the mirror and it would give you the best overall coating. But > you will need a long chamber with very very good vacuum for that. > > Not sure how you are using a variac and welder at the same time. > > I use my 2.5kva variac to power a 120 : 24 vac x 1500 watts stepdown > transformer. the 24 vac is just right to power 4 tungstens in series. > It took me a lot of experimentation to get the right number of emmitters > in series and parallel for my power supplies. Now I can start out > cherry red to wick the aluminum onto the tungsten then go to near white > hot for a few seconds then back to cherry and then off. If you hit the > power to fast the aluminum just melts and falls. that is very very very > bad for you mirror so dont ever let that happen. > > Andrew > > ____________ > > From: VacuumX@yahoogroups Behalf > Of radroy92 > Sent: Tuesday, July 01, 2008 5:36 PM > To: VacuumX@yahoogroups > Subject: [VacuumX] Re: "Yellow Box Coater" > > > > How many emitters would I need for a 12.5 mirror?? > > I checked my litle welder I'm planning on using for a supply for the > emmitters. My Variac was putting out 13 Amps at 120 Volts. The > welder was putting out 30 Amps at 30 Volts. This was with a 3.5 " > long coil of 3/32 stainless wire that measured 1.1 ohm. It was > glowing yellow hot laying on the concrete. Any more and it would > melt. It fused to the concrete and a few spots. > > Roy M. > > --- In VacuumX@yahoogroups > "Aurigema, Andrew N. (KSC)[ASRC > AEROSPACE]" > wrote: > > > > You can use single wire emmitters. James does. his emmitters are > about > > 1mm diameter bent into a U shape. I bought the tri-wire ones that > are > > pre twisted so i could put more aluminum on each strand. I only > have 24 > > emmitters and have to cover a 60" diameter disk so I needed to put > out > > some serious material. You cant put to much aluminunm on each wire > or > > the tungston disolves into the aluminum and you eat up the wires. > So I > > put 3 wires on each emmitter with three little strips of aluminum ( > > about 60 mg total ) and zap it with lots of current. > > > > Andrew > > > > ____________ > > > > From: VacuumX@yahoogroups > [mailto:VacuumX@yahoogroups 40yahoogroups. > Behalf > > Of radroy92 > > Sent: Tuesday, July 01, 2008 2:07 PM > > To: VacuumX@yahoogroups > > Subject: [VacuumX] Re: "Yellow Box Coater" > > > > > > > > Why do we have to use heavy emmitters like that can we use thinner > > wire? Or does it fall apart at those temperatures? > > > > Roy M. > > > > --- In VacuumX@yahoogroups > 40yahoogroups. > > "Aurigema, Andrew N. (KSC)[ASRC > > AEROSPACE]" > wrote: > > > > > > Get a big variac for that. I burned up a 1kw unit discovering > that > > they > > > are not rated to what they say they can take. go twice what you > > think > > > you need. You know you need a serious stepdown transformer to make > > > lots of amps at low voltage ( like 30 amps at 3 vac for each > > emmitter ). > > > > > > > > > I just chatted with James a few minutes ago so I know he is at > least > > > typing. He may not be monitoring this list right now. > > > > > > Andrew in sunny FLA > > > > > > > > > > > > ____________ > > > > > > From: VacuumX@yahoogroups > 40yahoogroups. > > [mailto:VacuumX@yahoogroups > > 40yahoogroups. > > Behalf > > > Of radroy92 > > > Sent: Monday, June 30, 2008 12:53 PM > > > To: VacuumX@yahoogroups > 40yahoogroups. > > > Subject: [VacuumX] Re: "Yellow Box Coater" > > > > > > > > > > > > --- In VacuumX@yahoogroups > 40yahoogroups. > > 40yahoogroups. > > > "glinos7124" wrote: > > > > > > > > > > > > Does anyone have any details on the Lerch/Jones box coater > > > > at the St. Petersburg Mirror Lab? > > > > > > > > Dimensions, materials, pumps, sensors,.... that kind of thing. > > > > > > > > I'm mulling over building one. > > > > It looks like a challenging, but doable project. > > > > > > > > tom > > > > > > > > > > By they way I'm working on a similar project. I have almost > > everything > > > and I'm hooking up power for my new TIG welder so I can assemble > > some > > > of the parts. I have purchased most of the parts from eBay and > the > > rest > > > came from the local Menards, a surplus metal supplier and some > > dumpster > > > diving. I'm currently on the tail end of cleaning my ancient NRC > 4" > > > diff. pump. Looks like somebody let it overheat and part of the > > > aluminum splash shield was fused to the bottom of the pump. For > my > > > initial chamber I have sectioned a 12" compressor tank and > > purchased an > > > angle flange from McMaster Carr to use in forming the sealing > > surface > > > at the open end. I have a small welder that I'm planning on using > > to > > > power the evap. coils and will controll it with a Variac. > > > > > > Roy M. > > > > > > |
|
I read that there are problems controlling highly inductive loads
with a simple variac since they break. There is a reason for this: they are not meant to be used with inductive loads, only resistive loads like lamps. The simple schematic that these variacs normally is built around isnt constructed to be used with inductive loads and could, depending on the load, be quickly destroyed. If a really heavy duty variac is used so will it hold just because the triac in it is bigger. I have a big microwaveoven transformer rated 2750W that i have rewound the secondary on. After that so did i get 5.4V and 1036A with shorted secondary but i needed to be able to control the output so i could control the temperature on the coils. I have now build a triac- based controller for highly inductive loads like an transformer are and i can now regulate the output power and the heat of the coil without any step from 0 to 100%. Thanks to that its meant to handle highly inductive loads so is a small 6A enough and its hardly gets warm with an output of 100A from the transformer. --- In VacuumX@..., "Aurigema, Andrew N. (KSC)[ASRC AEROSPACE]" <andrew.n.aurigema@...> wrote: they have. The catalog is a serious source of info.do not like max amp draw for very long......... they get hot and theinsulation on the winding breaksdown.Behalf Of radroy92Volts so I just plugged it into a 10 Amp Variac.You canstepdownuse a lot of emmitters ( 18 or so ) close up ( a few inchesaway ) ora lesser number farther back. In theory you could put one at thefocalpoint of the mirror and it would give you the best overallcoating. Butyou will need a long chamber with very very good vacuum for that. hittransformer. the 24 vac is just right to power 4 tungstens inseries.It took me a lot of experimentation to get the right number ofemmittersin series and parallel for my power supplies. Now I can start outwhite theverypower to fast the aluminum just melts and falls. that is very very40yahoogroups.com> ] Onbad for you mirror so dont ever let that happen.[mailto:VacuumX@... <mailto:VacuumX% BehalfareOf radroy92the thatabout1mm diameter bent into a U shape. I bought the tri-wire ones wires.areputpre twisted so i could put more aluminum on each strand. I onlyhave 24emmitters and have to cover a 60" diameter disk so I needed tooutwiresome serious material. You cant put to much aluminunm on eachorthe tungston disolves into the aluminum and you eat up the aluminumSo Iput 3 wires on each emmitter with three little strips of (40yahoogroups.com><mailto:VacuumX%40yahoogroups.com>about 60 mg total ) and zap it with lots of current. <mailto:VacuumX%40yahoogroups.com>you<mailto:VacuumX%40yahoogroups.com> ,"Aurigema, Andrew N. (KSC)[ASRCthat atmakethinkyou need. You know you need a serious stepdown transformer tolots of amps at low voltage ( like 30 amps at 3 vac for eachemmitter ). 40yahoogroups.com>leasttyping. He may not be monitoring this list right now. <mailto:VacuumX%40yahoogroups.com>40yahoogroups.com><mailto:VacuumX%40yahoogroups.com>[mailto:VacuumX@... <mailto:VacuumX% <mailto:VacuumX%40yahoogroups.com>40yahoogroups.com><mailto:VacuumX%<mailto:VacuumX%40yahoogroups.com> <mailto:VacuumX%thing. andassembleeverythingBy they way I'm working on a similar project. I have almost sometherestcame from the local Menards, a surplus metal supplier and theNRCdumpsterdiving. I'm currently on the tail end of cleaning my ancient4"diff. pump. Looks like somebody let it overheat and part of Foraluminum splash shield was fused to the bottom of the pump. myusinginitial chamber I have sectioned a 12" compressor tank andpurchased anangle flange from McMaster Carr to use in forming the sealingsurfaceat the open end. I have a small welder that I'm planning ontopower the evap. coils and will controll it with a Variac. |
|
they are inductive controler out there
toggle quoted message
Show quoted text
it is for vacuum fan in kitchen a bit inductive load but the load you have is very special at the beginning it is very loo resistor when the heat come the resistor increase and if the element cut no load this give you variation in load or spicke that is very difficult for inductive load and if you used only 100 amp on decondary try to have a tranformer whit a max capacity of 150 not 1030A you are in the lower part of the operating rage jack 47'N 71'W I read that there are problems controlling highly inductive loads |
|
The 100A was just an example, and the 1036A is when the secondary is
shorted and that would be over 5000W but that was just to say how much it can put out during a very few seconds nothing else. I will use more or less the entire capacity of the transformer later on but max would be 2300W because the fuse here is 10A and we use 230V so max is 2300W on the output which would be 425A as max with 5.4V which would be enough. Normally would i use everything between 160 - 425A so it need to be this big. But the transformer and the controling circuit i built works just fine even at only a few watts output with no problems at all and i have checked it in a oscilloscope and it works perfect no matter the output. Kitchen fans are not near as inductive as a big transformer so they could be controlled with a more or less ordinary variac schematic. --- In VacuumX@..., jacques savard <jacquessavard@...> wrote: resistor increase and if the element cut no loadwhit a max capacity of 150 not 1030Anormally is heavybuilt around isnt constructed to be used with inductive loads and isduty variac is used so will it hold just because the triac in it withbigger. so ishorted secondary but i needed to be able to control the output triac-could control the temperature on the coils. I have now build a arebased controller for highly inductive loads like an transformer handleand i can now regulate the output power and the heat of the coil stuffhighly inductive loads so is a small 6A enough and its hardly gets variactheyhave. The catalog is a serious source of info. Variacrated for 4kva ??? It better be or it will simply smoke. Ondo notlike max amp draw for very long......... they get hot and theinsulationon the winding breaksdown. welderBehalfOf radroy92 40yahoogroups.com> ,with a max output of 50 Amps at 45 volts or so. It runs on 120Voltsso I just plugged it into a 10 Amp Variac. the"Aurigema, Andrew N. (KSC)[ASRCYou that.focalpoint of the mirror and it would give you the best overallcoating. Butyou will need a long chamber with very very good vacuum for time. outstepdown nearcherry red to wick the aluminum onto the tungsten then go to 40yahoogroups.com>whitehithot for a few seconds then back to cherry and then off. If youtheverypower to fast the aluminum just melts and falls. that is veryverybad for you mirror so dont ever let that happen. for[mailto:VacuumX@... <mailto:VacuumX%40yahoogroups.com> ] OnBehalfOf radroy92 3.5 "theemmitters. My Variac was putting out 13 Amps at 120 Volts. The wouldlong coil of 3/32 stainless wire that measured 1.1 ohm. It was 40yahoogroups.com>melt. It fused to the concrete and a few spots. only<mailto:VacuumX%40yahoogroups.com> ,are"Aurigema, Andrew N. (KSC)[ASRC tohave 24emmitters and have to cover a 60" diameter disk so I needed eachputoutsome serious material. You cant put to much aluminunm on 40yahoogroups.com>wirewires.orthe tungston disolves into the aluminum and you eat up thealuminumSo Iput 3 wires on each emmitter with three little strips of(about 60 mg total ) and zap it with lots of current. 40yahoogroups.com><mailto:VacuumX%40yahoogroups.com>[mailto:VacuumX@... <mailto:VacuumX% 40yahoogroups.com><mailto:VacuumX% discovering<mailto:VacuumX%40yahoogroups.com>40yahoogroups.com>thinnerSubject: [VacuumX] Re: "Yellow Box Coater" whatthattheyare not rated to what they say they can take. go twice transformer toyouthinkyou need. You know you need a serious stepdown eachmakelots of amps at low voltage ( like 30 amps at 3 vac for isemmitter ). 40yahoogroups.com>at40yahoogroups.com>leasttyping. He may not be monitoring this list right now. coater<mailto:VacuumX%40yahoogroups.com>40yahoogroups.com><mailto:VacuumX%40yahoogroups.com>Subject: [VacuumX] Re: "Yellow Box Coater" almostthing.at the St. Petersburg Mirror Lab? ancientandassembleeverythingand I'm hooking up power for my new TIG welder so I cansomeof the parts. I have purchased most of the parts from eBaysometherestcame from the local Menards, a surplus metal supplier anddumpsterdiving. I'm currently on the tail end of cleaning my ofNRC4"diff. pump. Looks like somebody let it overheat and part pump.thealuminum splash shield was fused to the bottom of the sealingFormyinitial chamber I have sectioned a 12" compressor tank andpurchased anangle flange from McMaster Carr to use in forming the onsurfaceat the open end. I have a small welder that I'm planning usingtopower the evap. coils and will controll it with a Variac. |
|
a variac transformer can do the job at 6 amp easely and very safely not
toggle quoted message
Show quoted text
problemo whit short or spike of current a bit more expensive it is a variable transformer only sometime the old way to do the thing is still good jack 47'N 71'W The 100A was just an example, and the 1036A is when the secondary is |
|
Gomez Addams
On Jul 14, 2008, at 11:23 AM, henry_3507 wrote:
I read that there are problems controlling highly inductive loadsThere's something I'm missing here. 1. There is no triac in a variac. "Variac" is one of several trademarks for a variable transformer. "Powerstat" is another. A triac is a solid state switching device. You would not normally find one in or even associated with, a variable transformer. 2. Variable transformers are generally MUCH more robust and rugged than solid state switching devices. For decades, I and many other Tesla coil enthusiasts have been using variable transformers to control one of the worst (from an electrical standpoint) loads there is - disruptive discharge, spark gap type Tesla coils. The load is intermittent, highly inductive (due to large high voltage transformers) is intermittent due to the spark gap's firing, and often puts spits large amounts of RFI and high voltage spikes back toward the variac. Only recently (within the last ten years or so) have Tesla coil enthusiasts started building solid state controls that will handle a large (several kilowatts or more) Tesla coil without breaking. I have a big microwaveoven transformer rated 2750W that i haveOne thing you will discover after you've worked with solid state switching devices for a while, especially when you're doing phase angle control of inductive loads, is that two SCRs connected back-to -back are much more reliable, and handle surges and unexpected load behavior much better than a triac. If you compare an SCR and a TRIAC having identical PRV and I(f) ratings, you will find that the I(tsm) for the SCR is typically much larger than the TRIAC's. Greatly over-specifying the switching device is not the usual solution. The usual (and cheaper) solution to nasty loads (provided they remain generally within the safe operating area of the device) is to place a snubber network (can be as simple as a capacitor and resistor in series) across the device to limit the reverse voltage rise time appearing on the device's terminals. - Bill "Gomez" Lemieux |
|
Ok, there has been a real mixup here because in Sweden so is a triac
based regulator often called a variac since they do about the same thing as a transformer based depending on how you use it - control the power. The transformer based is normally not called variac but something else that describes exactly what it is. The international name is variac but it is very rarely used for the tranformer type here so i didnt got that it was the transformer based type that was meant. But then it all makes sense since some things just really didnt add up. So then just ignore all i said before since i was talking about a triac based control unit. --- In VacuumX@..., Gomez Addams <gomez@...> wrote: normally is heavybuilt around isnt constructed to be used with inductive loads and isduty variac is used so will it hold just because the triac in it trademarksbigger.There's something I'm missing here. for a variable transformer. "Powerstat" is another. A triac is asolid state switching device. You would not normally find one in or eventhan solid state switching devices.electrical standpoint) loads there is - disruptive discharge, spark gap typeTesla coils. The load is intermittent, highly inductive (due to largehigh voltage transformers) is intermittent due to the spark gap's firing,back toward the variac. Only recently (within the last ten years or so)that will handle a large (several kilowatts or more) Tesla coil withoutwith so ishorted secondary but i needed to be able to control the output triac-could control the temperature on the coils. I have now build a arebased controller for highly inductive loads like an transformer handleand i can now regulate the output power and the heat of the coil TRIAChighly inductive loads so is a small 6A enough and its hardly getsOne thing you will discover after you've worked with solid state having identical PRV and I(f) ratings, you will find that the I(tsm)solution. The usual (and cheaper) solution to nasty loads (provided theyremain generally within the safe operating area of the device) is to placea snubber network (can be as simple as a capacitor and resistor in |
|
ok
toggle quoted message
Show quoted text
i untherstand all that from the begiining i am a retired specialist in electronic and I repair some vacuum system mew one and old one and like i said the old one used variable transformer and the old technic still good in this case the veriable cherge in inductive and short circuit type or heating element give me a go for variable transformenr nas the cost is probaly need the same only the finist control a bit better on tiac system jack 47'N 71'W Ok, there has been a real mixup here because in Sweden so is a triac |
|
Ah ok, then i told anybody else that might wonder. Im electronic
educationed as well. For those who doesnt relly know; There is a big different on the output from the triac based and transformer based and they both have advantages and disadvantages. With the transformer based so could you regulate the output sinewave amplitude perfectly and still have a nice sinuswave all the time which could be absolutely crucial for some things, but these types weigh quit much and take up some room. The triac based is very small even those that could handle a lot of power but they doesnt change the sinuswave amplitude but instead sort of hacking the sinuswave up so they control the overall power instead. Both will work just fine to heat an coil in a vacuum system (with an transformer between that can ramp the current up) but the triac based is so much easier to build and if you would buy one so wouldnt it cost as much as the transformer based, especially not if higher power levels are involved. I have also build a little bigger triac based one for highly inductive or resistive loads that can handle up to 24KW but it isnt much bigger then the palm of a hand, and it is the cooling fins that take up all the place without the fins so would it be smaller than a hand. A transformer based one for 24KW would cost a lot of money take up a lot of room and weigh i dont know how much. --- In VacuumX@..., jacques savard <jacquessavard@...> wrote: specialist in electronic and I repair some vacuum systemtechnic still good in this case the veriable cherge in inductive andshort circuit type or heating element give me a go for variable transformenrnas the cost is probaly need the sametriac thebased regulator often called a variac since they do about the same basedtranformer type here so i didnt got that it was the transformer loadstype that was meant. But then it all makes sense since some things this:with a simple variac since they break. There is a reason for resistivethey are not meant to be used with inductive loads, only andnormally isloads like lamps. The simple schematic that these variacsbuilt around isnt constructed to be used with inductive loads reallycould, depending on the load, be quickly destroyed. If a itheavyduty variac is used so will it hold just because the triac in is aistrademarksbigger.There's something I'm missing here. evensolidstate switching device. You would not normally find one in or ruggedassociated with, a variable transformer. usingthansolid state switching devices. typevariable transformers to control one of the worst (from anelectricalstandpoint) loads there is - disruptive discharge, spark gap firing,Teslacoils. The load is intermittent, highly inductive (due to largehighvoltage transformers) is intermittent due to the spark gap's spikesand often puts spits large amounts of RFI and high voltage so)backtoward the variac. Only recently (within the last ten years or controlshave Tesla coil enthusiasts started building solid state withoutthatwill handle a large (several kilowatts or more) Tesla coil 1036Abreaking.I have a big microwaveoven transformer rated 2750W that i have outputwithshorted secondary but i needed to be able to control the transformerso itriac-could control the temperature on the coils. I have now build abased controller for highly inductive loads like an coilareand i can now regulate the output power and the heat of the getshandlewithout any step from 0 to 100%. Thanks to that its meant tohighly inductive loads so is a small 6A enough and its hardly phasewarm with an output of 100A from the transformer.One thing you will discover after you've worked with solid state back-toangle control of inductive loads, is that two SCRs connected load-back are much more reliable, and handle surges and unexpected (tsm)behavior much better than a triac. If you compare an SCR and aTRIAChaving identical PRV and I(f) ratings, you will find that the I placefor the SCR is typically much larger than the TRIAC's.solution. asnubber network (can be as simple as a capacitor and resistor in |
to navigate to use esc to dismiss