Ok, so I'm looking for an efficient way to utilize a 6/1 prime mover to direct charge a 48v battery bank. So another idea I've been entertaining is acquiring a 7-10 hp 3ph induction motor rated for 1725 rpm. Use the existing pulley from the ST-5 to belt it to the 6/1 and turn the motor 1800 rpm. Then add capacitors to one leg and adjust until output is around 100 vac. Feed the output into a 3ph bridge and take the output from the bridge into an MX60.
This config would also allow a quick change back to the ST-5 in the event of an inverter failure. I like redundancy.
Comments?
I guess it should work, as long as you chose the right motor. The wrong ones don't generate. I think that's covered on some of the conversion sites.
I have read, a couple of times that peps are taking the output from from an automotive alt, direct to mx80 and it works, it even works with the mppt controllers as long as you can turn off the mmpt. As when the controller sweeps for the mmpt, it cause the engine/alternator to drop the load causing an over rev.
Lloyd
It must not be an automotive alt with the avalanche diodes that clamp @ 30v.
When I'm charging w/ MX80 it's always in MPPT mode. It sweeps every little while. You can hear the listeroid spin a little faster and then slow down as it builds up load again. Doesn't really overrev.
the only problem i could see with using an induction motor turned induction generator, feeding an mx60 or 80
would be during load dump.
when the mppt samples the engine will speed up to its full governed speed or overshoot a bit which might cause an overvoltage
spike to the mx60/80
therefore if the mx60/80 has a upper voltage limit of 140vdc, i would set my induction generator to produce maybe 110volts max, so that
if and when it goes into load dump and speeds up the resulting voltage doesn't get higher than 140volts
i might also be tempted in using one of those varistors (sp) that clamps the voltage spike to help keep the voltage under what the max input
of the mx60/80 can handle. (i think it is a varistor that does this, although i might be wrong and someone will correct me)
bob g
Ok it looks like I'll make a full court press to make this happen.
Any comments on this bridge for the planned application?
http://www.mouser.com/ProductDetail/Ixys/VUO50-12NO3/?qs=sGAEpiMZZMuCl5o%252b%2fAuPoBTpCrezwdFeUjUWSt8MgpA%3d (http://www.mouser.com/ProductDetail/Ixys/VUO50-12NO3/?qs=sGAEpiMZZMuCl5o%252b%2fAuPoBTpCrezwdFeUjUWSt8MgpA%3d)
Quote from: Tom on October 06, 2011, 05:56:43 PM
Ok it looks like I'll make a full court press to make this happen.
Any comments on this bridge for the planned application?
http://www.mouser.com/ProductDetail/Ixys/VUO50-12NO3/?qs=sGAEpiMZZMuCl5o%252b%2fAuPoBTpCrezwdFeUjUWSt8MgpA%3d (http://www.mouser.com/ProductDetail/Ixys/VUO50-12NO3/?qs=sGAEpiMZZMuCl5o%252b%2fAuPoBTpCrezwdFeUjUWSt8MgpA%3d)
Just 58A cont, at 85C ?
http://ixapps.ixys.com/DataSheet/VUO50.pdf has great PEAK amp specs, but the repetitive amps is low. But better that stuff off ebay. Mouser is out of stock, what's the lead time ?
Didn't notice that there is a 16 week lead time. Guess I'll look else where.
Something like this shroud fit the bill.... http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2070379_-1 (http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2070379_-1)
Overkill but safe.
Or a whole lot cheaper: http://gb.suntekstore.com/3-Phase-Diode-Bridge-Rectifier-100A-1200V-SQL100A.html?&utm_source=gbus&utm_campaign=gbus (http://gb.suntekstore.com/3-Phase-Diode-Bridge-Rectifier-100A-1200V-SQL100A.html?&utm_source=gbus&utm_campaign=gbus)
Thanks Greg! Item from Suntek is now on order. Robin may have a motor for me. So things are underway.
Hey Tom,
any update on this project ?
veggie
Yes! A 2$ spring on the governor resolved most of the issues with the functioning of the current system. So this work around is not needed. A frequency meter and 2 volt meters were added to the system and that gave me the info needed about the lazy governor. Now that that is fixed the voltage is stable enough that the AVR does not need to be installed either. I do like to keep things simple. Being off-grid the attraction to me is that if the magic smoke comes out of the inverters, the generator can run the place with the flip of a couple of breakers.
Dear Tom,
Before I had generators...I simply routed legs from the three phase induction motor into the fuse box and ran the house directly. I had a fluke meter to set the engine governor to the right hertz, then arranged the capacitors to make the correct voltage. It was a limited but reliable system that cost $15 with no electronics.
I still have some 10hp GEs (oldsters with grease boxes) tucked away, for the "ya never know" times.
Nowadays, I would try the kill-a-watt meter to set the hertz and caps.
BPJ
Quote from: Dualfuel on January 06, 2014, 12:54:25 PM
Dear Tom,
Before I had generators...I simply routed legs from the three phase induction motor into the fuse box and ran the house directly. I had a fluke meter to set the engine governor to the right hertz, then arranged the capacitors to make the correct voltage. It was a limited but reliable system that cost $15 with no electronics.
I still have some 10hp GEs (oldsters with grease boxes) tucked away, for the "ya never know" times.
Nowadays, I would try the kill-a-watt meter to set the hertz and caps.
BPJ
How did you go with controlling the output with varying loads kicking in and out? Did you just run something like a set number of Lightbulbs or other fixed and constant loads?
My largest motor is a 5.5 Hp and like everything else I have read, I get significant variation in output with any variation in load. Running in C2C config is better but still variable.
Dear Glort,
I never used C2C. Like I said much earlier...I simply lay out the caps in the same pattern as the motor, Wye motors were best because I could pick out a 120v leg, (not your issue, there, I suppose.) A set of caps was configured for each voltage. I tried to keep everything equal but....well, turns out it wasn't rocket science, not with a big motor.
So with three legs, I would have the washing machine on one, the lights on another, and the third would up being devoted to powering an electric heating system for the fuel...
can't find the picture of it....prolly on another laptop...
Hmm, Normally I run my setup in delta as with the pulleys which are fixed on my Diesel and have defeated all Pullers I have been able to lay my hands on so far on the induction motor mean I have to rev the engine very hard to run in Wye.
I do have another 10 Hp motor up the shed that is brand new so I might drag that out. I have a pulley that fits that which would give a 1:1 ratio so I'll try that and see if I get more stability.
A bigger induction motor like yours may be a good part of the answer as well but they are not as easy to get here as 4- 5.5Kw units.
I'll keep looking though.
I have seen a few 20-50 Kw Motors lately going cheap which I'd love to hook up to my Mercedes engine but then I wonder what the hell I would do with all that power?
-THEROTECIALY- of course, ::) I could always run a 50A Circuit back to the switchboard and back feed my entire power bill in a day.* ;D
I have looked and emailed companies for a proper induction motor controller but so far have drawn a blank slate there.
* Only after having every saftey devise known to man installed by a qualified Tradesman and complying with every regulation ever cooked up and the blessing of the electrical utility and the pope and Dali Lama.