RLR
New member
- Location
- United States
Greetings all,
I have never posted before so please let me know where I stray.
I am a climate change scientistwho uses various resistance heaters to elevate surface and soil temperatures in forests. I have just custom built some probes from resistance heating cable. I have sucessfully used similar cable in other experiments for years. The probes are made from dual conductor heating cable and are 32" long (cable is 9.36 ohm/m with 12 w/ft output). There are 12 of them and they run in parrallel because they have to. I am using a PWM output and a zero crossing SSR relay to adjust voltage output to maintain my heating differential for the experiment based on temperature data. The experiment heats soils to be 2 C above ambient soils. I use between 9 and 12 soil probes on a given array and I have to transform voltage down 16 or 18V which I have been doing with a torroidal transformer so far with 240V supply. I rarely run these heaters at full capacity. Unfortunately to have the 500 VA capacity (calculated need is actually 384 VA) that I need. I either need to operate two 250VA transformers in parrallel (an easy solution) or buy a 500 kva buck boost transformer (16v at 500KVA). Can I split the load line and run two torroidal tranformers in parallel? I was planning on using triad magnetics VPT36940?
I am also wondering about voltage loss and positioning of transformer. It would be very efficient for my experiment layout to buy a single 2KVA buckboost transformer to run my whole system at low voltage. BUT my runs would be are long ~ 75-100 ft each. The other alternative would be to transform voltage very near experimental array. I was planning on using 10/3 or 12/3 SJEOOW to carry the load. For a given KVA, is voltage loss worse for low voltage (16V) or high voltage configuration (240). I could put use 500 KVA transformer near array if need be but that would mean added expense. This is a little unconventional as it is an experiment with experimental equipment. We put a premium on folkd safety and also keeping the experiment as pristine and untouched as possible.
Thanks for any help you can give.
I am a bit of a hillbilly engineer with respect to this stuff. Any advice would be appreciated.
I have never posted before so please let me know where I stray.
I am a climate change scientistwho uses various resistance heaters to elevate surface and soil temperatures in forests. I have just custom built some probes from resistance heating cable. I have sucessfully used similar cable in other experiments for years. The probes are made from dual conductor heating cable and are 32" long (cable is 9.36 ohm/m with 12 w/ft output). There are 12 of them and they run in parrallel because they have to. I am using a PWM output and a zero crossing SSR relay to adjust voltage output to maintain my heating differential for the experiment based on temperature data. The experiment heats soils to be 2 C above ambient soils. I use between 9 and 12 soil probes on a given array and I have to transform voltage down 16 or 18V which I have been doing with a torroidal transformer so far with 240V supply. I rarely run these heaters at full capacity. Unfortunately to have the 500 VA capacity (calculated need is actually 384 VA) that I need. I either need to operate two 250VA transformers in parrallel (an easy solution) or buy a 500 kva buck boost transformer (16v at 500KVA). Can I split the load line and run two torroidal tranformers in parallel? I was planning on using triad magnetics VPT36940?
I am also wondering about voltage loss and positioning of transformer. It would be very efficient for my experiment layout to buy a single 2KVA buckboost transformer to run my whole system at low voltage. BUT my runs would be are long ~ 75-100 ft each. The other alternative would be to transform voltage very near experimental array. I was planning on using 10/3 or 12/3 SJEOOW to carry the load. For a given KVA, is voltage loss worse for low voltage (16V) or high voltage configuration (240). I could put use 500 KVA transformer near array if need be but that would mean added expense. This is a little unconventional as it is an experiment with experimental equipment. We put a premium on folkd safety and also keeping the experiment as pristine and untouched as possible.
Thanks for any help you can give.
I am a bit of a hillbilly engineer with respect to this stuff. Any advice would be appreciated.
