Wanted: Some way to get about 1.5-2kw ish @ aprox 3-500v out of my 6hp lister...

[julian]

Ive got my lister running fine now, and ive accquired a 2nd hand 2.5kw SMA Sunny Boy grid tie inverter, but ive yet to sort out an item to actually generate the power.

Ive been looking at different options, inc 3ph induction motors and permenant magnet servo motors, but nothing perfect has presented itself yet.


Posting here in case anyone has anything that may be suitable?


Thank you,
Julian

(essex, uk)

[guydewdney]

2kw pmg as per renewablecomponents website (google miniwind) ? offer?

[julian]

2kw pmg as per renewablecomponents website (google miniwind) ? offer?

pm'd

[Other-Power]

I was going to suggest http://www.utterpower.com/products/pmg/ but they have stopped making them.

[julian]

Thank you,

At present, it looks like shipping a new windy-nation unit from the states is probably my best option.

This is also the unit Dick Jotec has been using for, i think, over a year now, in the same application, so i know it works (indeed, Dick's is actually the slightly earlier revision, and the latter one is supposed to be higher output)

Shipping and taxes will add far too much to the price, but, (un)fortunatly, its still significantly cheaper than any of the other options i have found.

[jotec]

You could try finding someone who is going to the States who may be prepared to bring one back as, paid, luggage?
Dick

[knighty]

why not a 3 phase generator, and then rectify the output ?

[julian]

ive been looking into IMAG stuff (as you may have seen on the veg forum) but the advantage of the PMAs seems to be that they have a much larger output range.

i may still give the imag stuff a go if i come across a near-free 3ph motor.

[knighty]

guessing you want to run at higher/lower rpm ?

do you want to run at a set output for long periods of time or change it all the time ?

like high in the winter low in the summer ?

you can set the output in the inverter and then it will put out that much moper no matter the voltage coming into it (as long as it's within range)

if you set it to 800watts, it doesn't matter is your engine is going at 900rpm or 1500rpm it will still output 800watts

[julian]

I *think* that the only way to alter the settings on the GTI are with a special cable that Dick has.

What i was planning ; ) was to visit Dick at some point, and do a 1-time setup using his cable.

Or i could buy myself the cable - but theyre so expensive that, if im to do that, i may as well just buy the proper PMA and have done with it anyhow!


However, for stage 2 of the plan, i will need the setup continiously variable (ie not just two settings) as ill want to get the generating kit to track the load.
The GTI has no idea as to the demand on the house side of it - it just puts out whatever its set to, and the flow is either to or from the grid, depending on the local demand.

This is great for most grid tie options, but rubbish for me, as i dont actually ever really want to feed to the grid (the only reason i have a GTI is to enable seamless linking between the two supplies - for when the engine is off or demand is higher than the engine output)

So, the 2nd part of my plan is to use a couple of current clamps to monitor the current at the connection to the load (the house) and the connecion from the gti, and have a little bit of electronics compare the two -

if (load>gti) speed up engine
if (load<gti) slow down engine

(within a pre-defined range, of course)

This way the engine rpm should control the voltage output, which should, in turn, using the software on the GTI, alter the load presented to the alternator, and the output from the GTI to the house.

Its a crazy way of doing things, i know, but i cant work out any other option to get the generating side to track the load, as the GTI blocks the usual feedback pathway.

[guydewdney]

whats wrong with a 'normal' generator, and leave the lister to maintain its speed, irrespective of load - thats what a diesel engine governor does. No pooters....

[knighty]

This way the engine rpm should control the voltage output, which should, in turn, using the software on the GTI, alter the load presented to the alternator, and the output from the GTI to the house.

Its a crazy way of doing things, i know, but i cant work out any other option to get the generating side to track the load, as the GTI blocks the usual feedback pathway.

I've been planning exactly the same thing for quite a while !

whats wrong with a 'normal' generator, and leave the lister to maintain its speed, irrespective of load - thats what a diesel engine governor does. No pooters....

is there a way to do it that way and easily adjust the output of the gti depending on power needed ?

[julian]

whats wrong with a 'normal' generator, and leave the lister to maintain its speed, irrespective of load - thats what a diesel engine governor does. No pooters....

Im not too bothered about the specific engine rpm, just its kw output.

The issue is that i want the kw output to track the load.  So i need a feedback pathway from the load to the engine.

A normal diesel generator system works by the regulator in the alternator effectivly trying to slow down the engine, and then the govenor does it thing, so the kw output goes up to match the load (i know you know all this ; )

But, as soon as the GTI is in the pathway, there's no immediate feedback from the load to the engine side.  Sure, i can set the engine to whatever speed, and itll maintain that speed, but the GTI will then always present the same load to the alternators regulator, and the kw output will be fixed.


I need a way for the GTI's output to be variable.  So it can track the load.  The only way that i can think of doing this is by using the GTI's input voltage to move up it software load curve and, hence, present more load to the engine.

I can not think of any other way.  If you can, im all ears!

Again, i want the GTI output to track the House power consumption.  I do not want to generate more power than needed (so i do not want to export) and i am using the GTI to seamlessly 'blend' the two (grid and generator) power sources.  I am not using the GTI as a tool to deliberatly feed into the grid at all - im simply using it as a device to maintain the supply to the house regardles of load or engine status.

[guydewdney]

the wind version of the aurora inverter has a wind speed input. I havent investigated it much, but it appears to be a frequency to power graph, where the frequency would normally be derived from the wind turnip, and it alters its power out accordingly.

[desperate]

Hey Julian, a bit late, but this is still kicking around in my garage..... Haywood 2hp elec  motor v heavy came off a floor sander.

Any use to you, we are near Kingston.

Desp