12V Inveter

Status
Not open for further replies.
LG, as to your generators output frequency. For a single phase generator: Generator Frequency (f) = Number of revolutions per minute of the engine (N) * Number of magnetic poles (P) / 120
Conversely, P = 120*f/N. So for 60 Hz. a two pole generator running at 3600 RPM will output 60 Hz or 3000 RPM will output 50 Hz. Lower RPM diesel types are generally a 4 pole generator so 60 Hz is 1800 RPM and 50 Hz would be 1500 RPM. Engin speed is normally controlled by a governor on the engine.

Back in 2007 we did major house renovations and that is when I added an 18 KW fully automatic system that runs on natural gas which we have as a utility to the house. Prior to that I had an old 4 KW (5 KW Surge) unit that runs on gasoline. Portable units like my old one are relatively inexpensive around here. A used but good 4 or 5 KW unit can be had for about $200 (USD) or less.

Ron
 
A 5KW here is alot more than that! Shame about the RPM's, the kabota PTO has 450 RPM and 850 RPM, but it is engine speed linked, so i could get 1500 off the PTO gear box, but it means high revving the engine.
S better to take power from a pulley attached to alternator, maybe you know who could weld one to the existing one, 1500 RPM off of that would be easy. PIC tachometer driving a servo connected to accelerator and some kind of PID control. .
I Think the engine bit wouldn't be a problem, it's the generator part that concern's me. Pointless taking it further than this, until i read up more on the generator part.
 
An 8 pole gen would operate around 850 revs, maybe a bit less.
Think of a 2 pole motor, it runs in sync with the gen at the power station at 3krm (ok not all power stations run at 3krevs, but we'll assume they do), a 4 pole motor 1440 revs and an 8 pole about half that (maybe a little quicker as slip isnt as noticeable) at about 800 revs, your gen is bery similar, assuming its synchronous which most are.
Commerical gens are often only approximate on frequency, unless its one of those inverter type things, but they seem to always break.
 
I started the engine this morning, it ticks over at around 650 rpm, so straight off the pulley would be good and more economical, there wouldnt be power loss via gearbox friction etc
See i do pay attention
 
There wouldnt be a great deal of friction in a drive belt, but your right you'd lose some power.
Also the max linear speed for most belts is 100ft/sec, or the life will be very much shortened, gearing up makes this problwm worse.
Use a proper industrial coupling, like a spider coupling, any mis-alignment is sorted out with the coupling and doesnt end up as vibration.
Yes you do listen, thats because your interested.
 
I was thinking more of the power loss from PTO gearbox, if I get dad to take the gearbox and PTO stuff off, then i can drive direct from the front or back flywheel thingy., its a Kabota so need to add a circuit to heat the plugs before trying to start it! they are crap cold starters without heat.
 
Looks like its time to expand on your knowledge base and add engine and mechanical drive systems to the list!

You can never know too much about how stuff works!
 
tcmtech said:
Looks like its time to expand on your knowledge base and add engine and mechanical drive systems to the list!

You can never know too much about how stuff works!
Click to expand...

While you are doing that you may want to keep in mind how much power (horsepower) you need to get what you want.

While 746 watts = 1.0 HP that would be an ideal world, unfortunately the real world is less than ideal. The creature needs to be able to deliver power when loads are applied. My little 4 KW (5 KW Surge) gasoline unit has an 8 HP engine running at 3600 RPM for 60 Hz power. So heed what tcmtech has to say.

Ron
 
Then as a rough guide, i would get around 8KW playing it on safe side. But it is a tough little diesel engine,3600RPM is in the plenty of grunt region. Just a guess but i would think going through the PTO i should get 10KW, I know that the figures dont add up, but I am not convinced it puts out the HP that is stated for it.
The engine has a twin that is in a compact tractor we use, it has alot of power for its size. Tiny 2 cylinder engine but pulls like a train! Failing that we have a ride on mower with a 3 cylinder diesel that puts out around 23 HP. The mower isnt now used as we have a new one. Loads of information you have given me, Obviously now i need to do some background reading up!
 
If you had some engine model numbers I can probably track down the basic power curve specs so you would have a reasonable idea of what usable power you may have available at different RPM's.
 
Personaly I owuldnt take off the g/box and stuff the amount you lose is very small, but if you really want go ahead.
I converted my wifes landy into a diesel and despite having more than enough electronics knowledge to make the heater plugs all electronc, I didnt for reliability theres just a pushbutton and a high current relay, the driver gets to say how long heat is applied for not some circuit that can get it wrong, and theres very little to go wrong.
Power ratings for diesels vary a lot, some quote the max power by the amount the engine revs drop, some (most) quote the amount of power you can take with the engine at full throttle and the rpm at the max torque which is usually 2k2 revs, and some quote the max power that the engine can provide without excessive wear which is the one you really need to be operating it at.
 
The Kabota is a small compact tractor, it has always been seen as mine, as I am the one that mainly uses it. I am lucky that it is a very simple rugged machine, that I grew up on. So i am pretty good with its parts .
The heater is simple relay on it, so plug control nice and easy, summer or winter turn key to plug heat, count to 18 and start simples
 
I often borrow fork lifts at work to shift stuff, the ones that are the sam eas your kubota are better to start, the colder it is th emore you count, the later electronically controlled ones allways take 3 or 4 goes to get going, and th eplugs cut out as soon as the engine fires so it stalls when you set off, I think they must have been designed in a warmer climate.
Too much electronics can make a mess of things.
 
All i would do for auto start is, Pull plug relay in, start count, release relay, turn engine set number of times (say 4 turns), test for start condition (monitor alternator for any output), if no output repeat with smaller relay count on plugs. But I agree they are utterly reliable engines! Dads big tractor is pretty modern, and can be a real pain to start. my little Kabota starts every time! and is 28 years old!
 
Not all diesels use glow plugs, some esp boat engines use a flame plug, it has its own pump and glow plug, the glow plug glows and the pump squirts fuel across it lighting it creating a flame warming the intake air, when they work they are great but when a few years old can be a right pain in the...
 
The Kabota engine we have uses glow plugs, there is a small hole in the dash, on the tractor with same engine, inside the hole is a small coil, you turn the key to glow plug and wait until you see the little coil glow, then turn to start
 
So we started with inverters and now we are up to diesel engine starting systems?

Kinda gets complicated real fast when you are trying to do DIY backup power doesn't it?

I've had to work with diesel engine for years. I like glow plugs and intake grid heaters but those flame plug designs are the worst for function and reliability.

The only flame based system I have ever seen that works well is a propane torch down the engines throat while it's being cranked over.
 
Ok till the torch goes out and the rings break.
They used to fit wiffy bottles to leyland engines from the factory, not many others did.
I've seen tha damage that stuff does.
 
Status
Not open for further replies.

Similar threads

C
  • Question
Constant current / constant voltage 12V battery charger questions?
Replies
4
Views
2K
crutschow
P
  • Question
"Reverse" the result of 12v "Safety" Toggle switches operation
Replies
15
Views
2K
Pepsikid51
P
D
  • Question
12v rail smoothing?
Replies
10
Views
2K
danadak
D
  • Question
12v multi input switch?
Replies
5
Views
1K
Nigel Goodwin
T
  • Question
12V 10A to USB-C?
Replies
16
Views
5K
thatonenerd
T
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…