Electronics

The74namesofgod · Joined: 01 Jun 2008 Posts: 5

hello I am trying to build a 10-20 KW induction heater. i dont know much about electonics so i need alot of help. im not sure but i think i can run transformers together to more watts. i have found some caps for the work coil im not sure but i think there 17.1 amps and there 0.1 uf 250 volts. i should need 200-500 caps. the rest i dont have a clue about please help please check if i got the right amps for the cap i could have made an error. thanks

a link to cap data sheet
http://www.epcos.com/inf/20/20/db/fc_05/MKP_B32651_56.pdf

a link to the cap
http://www.epcos.com/web/generator/Web/Sections/ProductSearch/Hitlist/Capacitors/FilmCapacitors/MetallizedPolypropylene/Page,locale=en.html?param_c_r=0.1&param_c_r_tol=&param_v_rms=250&param_dv_dt=975&from=searchform&doAction=searchform&distributorId=0&cssurl=&shop=no

neon · Joined: 25 Feb 2006 Posts: 598

what do you mean together? in series in parallel? for 20 40kw that is quite of bit of watts. capacitors values is what you need but more inportant for now is the voltage you just cannot put a 10mfd into just any circuit just because you hapopen to have one there otherwise it is new year immidiately. get the message??

The74namesofgod · Joined: 01 Jun 2008 Posts: 5

i was going to have 250 volts AC across the caps. they are rated for 250 v ac. i think i need 20 to 50 uf. the caps are for the work coil. the transformers i will have are 5000 watts each and i need to put 3 to 4 together to make 15000 to 20000 watts. they are from welders and i dont know anything else about the transformers at this time. i think i will have to rewind the transformers. i got one welder from a guy for free but it works and now i cant use it have 2 more that i have to go get, and i will have them soon. i have 3 (3phase) converters comming so i can make a gas powered generator from them that will supply the power i need.i do want to know if i got the amps right on the caps 250V*2pi*10900Hz*0.1uf=17.1 amps

The74namesofgod · Joined: 01 Jun 2008 Posts: 5

i will put the transformers in parallel

neon · Joined: 25 Feb 2006 Posts: 598

first of all transformers do not come at 100% efficiency expect to loose quite a bit of power as in heat. you got the advice to put them in parallel that only works if the primary is 240v ac. here is another thing that is called phase transformers must be in phase and with the sanme output voltage before you can say put them anywhere. in parallel. a lower voltage on one will act as a load to the other 180 degrees out of phase then you got a short with or without any load.

The74namesofgod · Joined: 01 Jun 2008 Posts: 5

what if i made it dc then 20-100 KHz ac then tough the transformers

neon · Joined: 25 Feb 2006 Posts: 598

ha now that is different still the same problem sharing the load how are you going to share the load obviously the higher power tranf. is going to be dominant. think of battery both 9v but one is somewhat week then the good one will try to supply power for the week one is overworking one is loafing. solution add a very small resistor to share the load ineficient as hell wasting power but it will work.

The74namesofgod · Joined: 01 Jun 2008 Posts: 5

ok this is going to sound stupid what if i run 250 V dc though an alternator from a car its 3 phase and rated for 200 amp at 12 volts so i need like 80 amp at 250 volts yeah its 10 times but i dont care if i break it i could cool it with water maybe and try to spin it at 30000 rpm....this wont work but i will try it unless there is some problem that im overlooking

neon · Joined: 25 Feb 2006 Posts: 598

30,000 rpm do you have any idea the containament field required if it blows up. quit coming up with lame ideas i will not answer you any more, I ca be held responsible if i suggest crazy stuff for you to try. as they say in MEXICO adios amigo.

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