Search found 239 matches

by groper
Fri Jan 29, 2016 11:36 am
Forum: Plumbing
Topic: Desalinator [moved from MV Catapult build]
Replies: 56
Views: 53408

Re: MV catapult

My setup is going to be run from AC power fed from the inverter. As I will have a variable speed drive running it, i can control the output of the system to whatever I like. I will likely find the best balance of output vs power consumption and just let it run there. But as 44c noted, the output can...
by groper
Thu Jan 28, 2016 7:03 pm
Forum: Plumbing
Topic: Desalinator [moved from MV Catapult build]
Replies: 56
Views: 53408

Re: MV catapult

Gerald - i can make anything electrical work - i do it for a living :) I can size the pump and motor which will work for you but there is no such thing as a free lunch - the more power you use the more water you will make and visa versa. So going with a really small current draw just means you have ...
by groper
Thu Jan 28, 2016 8:36 am
Forum: Plumbing
Topic: Desalinator [moved from MV Catapult build]
Replies: 56
Views: 53408

Re: MV catapult

2 housings and 2 membranes costs more than 1 twice it's size. The 2540 is more than twice the length of 2514 and thus it has more surface area. So it should produce more water and cost less - the problem I can forsee is that the flow is so small that the membrane will not have sufficient flow across...
by groper
Sun Jan 24, 2016 9:26 am
Forum: Plumbing
Topic: Desalinator [moved from MV Catapult build]
Replies: 56
Views: 53408

Re: MV catapult

The compressor isnt as nearly as noisy as the petrol engine powered versions - obviously there isnt a combustion engine running it. But its still noisy, just the pistons of the compressor do make a bit of noise - at full speed its the same as any other small size electric motor and belt driven air c...
by groper
Sat Jan 23, 2016 4:58 pm
Forum: Plumbing
Topic: Desalinator [moved from MV Catapult build]
Replies: 56
Views: 53408

Re: MV catapult

Good news - my varibale speed drive arrived on friday and i connected it all to the dive compressor... it ran fine on plugged into the mains but kept tripping the inverter when i tried to run it from the boat... good news is i added an inductor to the line as a line filter and everything is now ok -...
by groper
Sat Jan 23, 2016 10:02 am
Forum: Plumbing
Topic: Desalinator [moved from MV Catapult build]
Replies: 56
Views: 53408

Re: MV catapult

Our system is a bit cheaper than $4400... more like $3500 -(should be a little less than this but until i have all the pieces installed i dont wanna say as we all know the incidental costs can add up - the main thing i dont know yet is what the high pressure hoses and fitting are going to cost once ...
by groper
Fri Jan 22, 2016 7:59 am
Forum: Plumbing
Topic: Desalinator [moved from MV Catapult build]
Replies: 56
Views: 53408

Re: MV catapult

I have found other motors which you could use... they are available here in OZ, 240VAC motors which will fit on that pump down to 370W. And also 12V motors which go upto 375w etc... choice is yours... If you cant find something that works for you - we can make it work or just build your own like we ...
by groper
Thu Jan 21, 2016 11:49 pm
Forum: Plumbing
Topic: Desalinator [moved from MV Catapult build]
Replies: 56
Views: 53408

Re: MV catapult

And one more thing about big motors... Induction motors typically use between 5 and 8 times their full load current on startup - its called inrush current, and its so large because the rotor is not turning and their is no inductive reactance to provide any other impedance to current flow. Only the r...
by groper
Thu Jan 21, 2016 11:35 pm
Forum: Plumbing
Topic: Desalinator [moved from MV Catapult build]
Replies: 56
Views: 53408

Re: MV catapult

Gerald - if you only have 1 battery - and it is 12v 150ah - then you can only realistically use half of that or you will kill your battery in no time - even 50% depth of discharge is pushing it, a 30% DoD is a typical design goal for a lead acid battery. So you have at best 12v * 75ah = 0.9kwh to bu...
by groper
Wed Jan 20, 2016 9:54 pm
Forum: Plumbing
Topic: Desalinator [moved from MV Catapult build]
Replies: 56
Views: 53408

Re: MV catapult

Ive bought a few inverters off ebay for various purposes, they all seem to work fine... but to start an decent size induction motor you need a BIG inverter, buy the biggest one you can find - 3000W is the biggest 12v inverter ive found. Go to ebay and search "Giandel". The 3000W pure sine ...