just signed on, was wondering the web and came across this place. first i better say a little bout who i be, I'm a ham as of 25+ yrs ago, A class , n4isf, was krazy over electronics and studied basic radio quite throughly up to about 20 yrs of age, (i'm 40 now) (still have a good size collection of electronic junk to pull spare parts from.) then we bought land in the hills of tn and i drifted into logging/sawmilling, horses, agriculture, etc. got backhoe and dozer and been doing jobs with them, but now i'm backing off on those off the farm jobs and persuing getting a production greenhouse started and some land cleared for pasture.
Now i have a little project to persue.
I need to turn on a 7.5 hp 3 phase moter with a thermostat, (blower to cool a greenhouse) and I'm not going to buy an expensive contactor to do it. ($350) as that would only do part of what needs doing anyway, because I only have 1 phase power to run it.
My tenative design; The therm. contacts will turn on a transistor powered relay which will turn on a small 1 phase motor, belt drive starting a 3hp or larger 3 phase motor for a phase converter, a delay circuit will then turn on the power to the 3 phase motor and interupt the power to the 1 phase motor at the same time, then a second delay circuit will turn on some large relays(by way of a small one) to turn on the big blower. I'm thinking of trying ford/AMC starter relays for the big relays, but they are intermitant duty, so i need to do a current limiting resistor/capacitor setup to prevent the coils from over heating. i never heard of using 12 V starter relays for 240V but i don't see any reason it won't work, the coil is normally isolatable from the main contacts. I pick up motors from the local scrap yard for $0.15 a pound, some are new or next to it. (that's where the big blowers came from, i have 2, a 7.5hp and a 20hp, the 20 will go on a big double size greenhouse later, and they are new, never been hooked up, found them sitting there last year.)
PS: another little project my brother and i have been playing with off and on, installing an electric forklift motor in a compact car, we got forklift parts from the scrap yard too, and going to hook up the big transistors on the control board to drive it, with a 555 ic variable pulse width osciliator driving them. run it on 4 normal size deepcycle marine batterys, going to add a 13 hp honda engine to drive a couple welding size alternators to provide average power. (one of which also came from the s yard.) Then there's another device in the works we want to add to it, I've played with them in the past, my neighbor has too, and he had one working for awile in excess of 20 yrs ago. the best way to tell ya what it is, is to read this 25 pg. story;
http://216.239.51.104/search?q=cache:GZX8vvELR4EJ:byronw.www1host.com/files/Gone%2520to%2520China,%2520AC%26theFIVS605.pdf+T76+aluminum&hl=en&ie=UTF-8
my projection of expected mpg for the car is around 400-480.
a future project still in dream stage is a ton truck with same setup, should be able to easily get 150 with one, it would use either 84 or 112 hp EV motors, (3 or 4 28's) and probably 20 batterys, with a small car engine running on a "fuel processor" generating around 40 KW.
one neat thing about the hybred EV, plug in cables and it's a DC welder. oh well!! gabatchya suhmore later. RT
Now i have a little project to persue.
I need to turn on a 7.5 hp 3 phase moter with a thermostat, (blower to cool a greenhouse) and I'm not going to buy an expensive contactor to do it. ($350) as that would only do part of what needs doing anyway, because I only have 1 phase power to run it.
My tenative design; The therm. contacts will turn on a transistor powered relay which will turn on a small 1 phase motor, belt drive starting a 3hp or larger 3 phase motor for a phase converter, a delay circuit will then turn on the power to the 3 phase motor and interupt the power to the 1 phase motor at the same time, then a second delay circuit will turn on some large relays(by way of a small one) to turn on the big blower. I'm thinking of trying ford/AMC starter relays for the big relays, but they are intermitant duty, so i need to do a current limiting resistor/capacitor setup to prevent the coils from over heating. i never heard of using 12 V starter relays for 240V but i don't see any reason it won't work, the coil is normally isolatable from the main contacts. I pick up motors from the local scrap yard for $0.15 a pound, some are new or next to it. (that's where the big blowers came from, i have 2, a 7.5hp and a 20hp, the 20 will go on a big double size greenhouse later, and they are new, never been hooked up, found them sitting there last year.)
PS: another little project my brother and i have been playing with off and on, installing an electric forklift motor in a compact car, we got forklift parts from the scrap yard too, and going to hook up the big transistors on the control board to drive it, with a 555 ic variable pulse width osciliator driving them. run it on 4 normal size deepcycle marine batterys, going to add a 13 hp honda engine to drive a couple welding size alternators to provide average power. (one of which also came from the s yard.) Then there's another device in the works we want to add to it, I've played with them in the past, my neighbor has too, and he had one working for awile in excess of 20 yrs ago. the best way to tell ya what it is, is to read this 25 pg. story;
http://216.239.51.104/search?q=cache:GZX8vvELR4EJ:byronw.www1host.com/files/Gone%2520to%2520China,%2520AC%26theFIVS605.pdf+T76+aluminum&hl=en&ie=UTF-8
my projection of expected mpg for the car is around 400-480.
a future project still in dream stage is a ton truck with same setup, should be able to easily get 150 with one, it would use either 84 or 112 hp EV motors, (3 or 4 28's) and probably 20 batterys, with a small car engine running on a "fuel processor" generating around 40 KW.
one neat thing about the hybred EV, plug in cables and it's a DC welder. oh well!! gabatchya suhmore later. RT
