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Forum Index : Electronics : petrol gen wiring
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Madness Guru  Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Has anyone tried connecting an unmodified F&P to a grid tie inverter via a rectifier? There are only 10 types of people in the world: those who understand binary, and those who don't. |
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renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
I scored a new 36 pole stator, it's a bugger get out the centre plastic bit. I like the way Highlander did that mount with the red pulley and the two bearing carriers on both sides. Reckon I'll copy that. Cheers Mark Cheers Caveman Mark Off grid eastern Melb |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
I might try that, I have an un f'd with 36 stator, Was just doing the wiring for the star delta config on the 42 today, jeez, bloody tedious, only got 1/3 done. Have to decide on petrol or diesel motor to run the bastard. Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Just be careful of the voltage, firstly the danger of 400 maybe 500 volts, secondly, it will take a minute before the GTI will connect and load down the generator. During that time keep the RPM down otherwise you may end up with too many volts. The GTI will also not be happy if there is not at least 1 megaohm resistance to ground. I have a couple inverter AC compressors that I will cut open and see if there is any potential for them to be used as generators. They are basically the same type of motor as an F&P but with the magnets on the inside like a conventional motor. But they are made for much higher power than an F&P washing machine, a small one is around 600 watts bigger ones are up in the region of 5KW and beyond. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
That will be a while off mate, prob Feb, I'll give you a yell before I do it. Cheers mate merry xmas to everyone. Cheers Caveman Mark Off grid eastern Melb |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
This is a good point. I had a lot of trouble with this when trying to use an IMAG to an inverter. Unloaded the revs had to be kept within spec which wasn't easy without going over voltage. As soon as the inverter kicked in and started ramping up, the voltage and the engine would sag and often drop below the inverters minimum which would make it disconnect then it would take another minute of self tests to re engage. Successful couplings were hard to achieve and usually caused a lot of swings in the engine and output as the inverter ramped itself up and down. To get around this one needs a lot of reactive power in the engine to over come the sudden loading. The inverters electronics will always be faster than the engines mechanical Governor. Given the inherent Torque of a diesel over a petrol motor, and the subsequent reactive power, the oil burner would be a good choice for this application. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Thanks George, I'll keep a look out for the diesel engines. I primarily want it for a constant charger though, so a cheaper keystart petrol will be 1/3 the price but depends on what sales are happening. BTW what's IMAG? Cheers Caveman Mark Off grid eastern Melb |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
Induction Motor As Generator. In this case 3 Phase motor wired up in a C2C Configuration ( capacitors across 2 legs to make is single phase) I would not expect an F&P motor to be AS touchy but certainly I would think the loading and initial coupling would need close monitoring of initial and constant voltage. The inverters being MPPT seem to hunt for the sweet spot of output ramping up and backing off the loading to get the best combination of output. If the engine has not got a good govenor and plenty of torque, this causes a lot of up and down of the engine revs. My conclusion in playing round with the IMAG which I think would be applicable to any engine driven setup was you really want the engine and generator to be over size for the inverter. This way the inverter will just max out and stay there providing a constant load on the engine and won't be up and down trying to find where the most power is. If the inverter has more capacity than the motor/ generator combination it can always pull them down too far and will try to as the inverer is always going to try and achieve it's max output. If the inverter is below the max capeable output, it can only pull to it's rating which leaves the engine and generator happily within their power curve and not overly stressed or having to deal with a constantly varing load. As an example, a 5kw inverter on a 4 KW generator is going to try and pull up to 5KW. It will over power the generator the when the output falls or maxes out, it will back off a bit. Volts will come up, the inveter will think there is more there so increase load, overpower and pull down the motor and generator again and so it keeps going with output like a see saw. If the generator is 5 KW and the Inverter is 4, the inverter will ramp to it's max then when there it will pretty much stay pegged. might back off a few watts but as soon as it sense's still plenty of power it will go over a few watts. Won't be enough to upset the gen and the output will be constant as will engine speed. I have never tried this with a generator with an AVR which may compensate a bit ( or fight with the inverter) but I still think the motor and generator will need to be over size for the inverter to ensure smooth and stable running unless there is a way to electronically limit an oversize inverters current draw to under that of the genny. |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
If you put a run capacitor in series before the rectifier it will reduce the current, you would have to play around with cap values. This would allow you to run a smaller generator than the GTI, secondhand GTI's are cheap so a 1.5 KW GTI on a 3KW petrol generator would run happily. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Yes, the generator with cap in series with the ac line, makes them all play properly. The cap will effect PF positively, but allows the mppt to work with it. It can fiddle about, and find the best power transfer, and the motor does not need to bother too much at all. Use this on an outer island down at the wool shed, to charge batteries back at the house 100 yards away or so..... keeps the noise down in winter when you need it at night to supplement the shortened days power if overcast. It runs into a 3kw aerosharp with a 2500 watt genny ........oztules Village idiot...or... just another hack out of his depth |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
Stupid question, but would a heavy flywheel help in this instance to help smooth out the changes in engine revs? |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
"Stupid question, but would a heavy flywheel help in this instance to help smooth out the changes in engine revs? " This just changes the hysteresis in the system... the same results will occur, but in slow motion. The one caveat may be that the engine has a longer time to try to increase or decrease the power, but the same thing applies, it will hunt as the mppt changes from high to low and back again. A cap or group of caps will solve this from practical experience.... it's that simple. ( I like simple) .......oztules Village idiot...or... just another hack out of his depth |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
No worries, I was just thinking if the engine had more time to respond, it would give it a better chance of getting power up or down as required, those mechanical governors arent the quickest to respond, but if the caps work, all to the good |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Reminds me of a generator I had many years ago it had a Ronaldson Tippet 8HP Diesel with a huge flywheel and only did 800 RPM. When we were building the builder had a 13 HP honda generator, everytime they pulled the trigger on their circular saw it grunted and groaned. Then it died eventually and they were using my old generator, starting the saw did not even register, it just kept bopping along just slightly louder. But GTI's don't have big startup surges, they will just go up to their rated power, if the generator takes slightly longer to get their it won't matter unless the DC input volts drops below the GTI's threshold to disconnect. But the GTI should back off if that happened anyway. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
What a pisser! have a look at the start on P1, this started by a fella running a motor in a paddock hooked upto a F&P 10 years ago. Now it's progressed to being connected to GTI's. Ahh bloody technology. Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
You could go back to melting down animal fat to burn for light. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
HAHAHAHAH sorry mate didn't want to come across like the Unabomber, just thought it was amusing how a thread developed over a 10 year period. Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Didn't realise it is so old, might be up for heritage listing then, not very often a thread that old gets exhumed. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Hey guys I wired a 42 pole to 7x2 star delta like the instructions as per this.  So to get delta do you connect Z to Z1, Y to Y1, X to X1 And star connect Z1, Y1 and X1 together? Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
This might help  From There are only 10 types of people in the world: those who understand binary, and those who don't. |
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