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Forum Index : Electronics : Electronics Design Help Needed?
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WindyMiller Regular Member  Joined: 05/04/2011 Location: United StatesPosts: 62 |
GidDay! I have a engineering question for those that can help me out? I am in the process of converting a 2 HP Dayton electric motor into a petrol driven induction generator unit. This is pilot test for a larger unit of 5 to 10KW. My question is in regards to the following issues. 1. The book I am going by for this conversion is "Motors as Generators for Micro-Hydro Power" By Nigel Smith. This book is indespensible for those who are interested in Induction Generators. The problem is I live in the United States and to obtain the Induction Generator Controller schematics? You have to attend a ITDG approved course to get at the Mark-Space Controller design? The problem is I do not have the means to travel across the pond to England to attend one of the courses? So does anyone have the specific control unit in question that can share it with me? I am thinking of writing Nigel and see what I can work out with the ITDG folks? Without this controller my generator is as good as scrap metal as these things need a proper controller, and the ITDG design by Nigel Smith is exactly what I am looking for and in need of. I have looked at other controllers and have not found anything else suitable? 2. This is really more a agrovation than anything else. On page 80 of the above mentioned book is a small circuit used for pfe on starting of an AC electric motor load. This little circuit uses a Diode bridge, a few resistors, two or three motor run capacitors of about 10UF, and a DC operated solid State Relay that switches in a Motor Start Capacitor that is the main PFE cap for about 0.5 to 1.5 seconds. This capacitor is of 270-324 MFD. My problem is I cannot find a simple schematic on the web of a commerically made DC operated Solid State Relay of the amperage rating I need? I only like to copy existing proven designs for obveious reasons. However I found a nice AC Solid State Relay article in PDF format by Rodney Kreuter. The article is from Radio Electronics Mag from around 1991. The PDF I found on the web a long time ago while searching for Solid State Relays. My question is for those who have a copy of the book and can look at this circuit? Would it be possible to remove the diodes and use an AC solid state relay? This is the name of the PDF Solid%20State%20Relay.pdf Or is it possible to make a simple 120 Volt DC to 120 Volt AC power source to operate the AC solid State relay of the mentioned PDF which would charge the capacitor and switch it in and out? instead of purchasing a DC operated Solid State Relay which are expensive here in the US? What about using one of those cheap 100W power inverters you find for laptop charging. They are really cheap and available every place over here? I would imagine that one could use a DC to DC converter to somehow bring the 120 Volt DC done to 12 volts to feed the simple little power inverter which then would operate the relay and charge the cap which hopefully would switch off when it is supposed to so it does not go BANG. The motivation behind building my own relays is that I simply do not have alot of money and I have 5 large boxes of old circuit boards and other junk with most if not all of the parts I will need for the relay. I also would rather build a proper DC solid state relay just for the simple pleasure I get also from building things. I also suffer from wanting over engineer things whenever possible! Robert |
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| VK4AYQ Guru  Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Robert The people that do the breezy conversion may be able to help. http://www.prairieturbines.com/ All the best Bob Foolin Around |
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| WindyMiller Regular Member Joined: 05/04/2011 Location: United StatesPosts: 62 |
Bob, I will have a look at the link? Thank you for replying. Robert |
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| WindyMiller Regular Member Joined: 05/04/2011 Location: United StatesPosts: 62 |
Bob, After looking at the mentioned link I did not really come across anything helpful? I did contact them awhile back and they were unable to help. I guess what I need most right now is a good working schematic for a DC to DC converter to convert 120 Volts or more DC to 12 or 14 volts DC at 100 Watts of power? Or maybe 11 amps output. I have not found anything of a schematic for such a beast? Although I believe someone probably has such a drawing. Robert |
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| WindyMiller Regular Member Joined: 05/04/2011 Location: United StatesPosts: 62 |
Update, For the few who maybe watching this post? I finally did find a reasonable price for the converter I am looking for http://www.trcelectronics.com/Meanwell/sd-100d-12.shtml However the unit would come in above the price of a DC operated solid state relay so for now I have hit a moot point. It would be just simpler to buy the DC OP SSR which I found on Ebay some from the US, and some from China. I personally hate Chinese engineering. So I would go for the US or Canadian built units. Robert |
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