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Author Topic: Low voltage  (Read 10345 times)

Joe

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Re: Low voltage
« Reply #15 on: August 31, 2006, 03:07:35 AM »
What you would be looking for is a full-wave bridge rectifier.  There are a lot of different sizes...I don't remember where I got the size info...but If I had to guess it would be from George's CD...I do believe they are available from him also...good to have a spare...then you'll never need it.  :)

Joe
Nothing is easy...if it were...anybody could do it.

2005 Power Solutions  6/1-ST5

dkwflight

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Re: Low voltage
« Reply #16 on: September 02, 2006, 09:15:59 PM »
Hi I took a pic of theheatsink and diode. here it is.

http://s29.photobucket.com/albums/c294/dkwflight/?action=view&current=100_0164.jpg&refPage=&imgAnch=imgAnch1

As you can see I haven't mounted it yet.
 :D I need to clean the sooty oil up too!
Dennis
28/2 powersolutions JKSon -20k gen head
Still in devlopment for 24/7 operation, 77 hours running time

Joe

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Re: Low voltage
« Reply #17 on: September 03, 2006, 02:26:37 AM »
Found the diodes I got on ebay in Dec 05...have had them tucked away since then and not had a chance to do anything with them yet...
The only number on it is KBPC3510...don't know if this is a good replacement for the Chinese arangement  that is standard on an ST 5kw...when dealing with electrical componets I would do more research and find a more credible source as to size than some unknown stranger on the net (me).

Joe
Nothing is easy...if it were...anybody could do it.

2005 Power Solutions  6/1-ST5

dkwflight

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Re: Low voltage
« Reply #18 on: September 03, 2006, 05:00:13 AM »
Hi I don't think the values are too critical.
I ran the gen with the heatsink under a good load to day. no problems with ir. It ran cool, maybe 1 degree above ambient.

I had some problems with throwing the belt  tho. I had alowed the gen to get oput of alignmenmt with the drive pulley. Use a long straight edge to chec. put it across the driven pulley edge and look at the belt spacing.
Dennis
« Last Edit: September 03, 2006, 05:04:00 AM by dkwflight »
28/2 powersolutions JKSon -20k gen head
Still in devlopment for 24/7 operation, 77 hours running time

bitsnpieces1

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Re: Low voltage
« Reply #19 on: September 03, 2006, 06:50:47 PM »
Guys....I'm a machinist not a "sparkey" I have done lots of wireing 3phase and single......but never a bridge rectifier. I can take it apart and put it back togeather but rectifier values.... ???....I'm in part number land...I did do a e-bay search and found the "archer" one ....but what are the nessary values it has to have?...Radio Shack has em in stock...easy!

Peak reverse volt 50v
rectified current   25a
Forward volt drop 1.7v
reverse leakage at PRV 100ua

Of course a diode conducts electricity one way and (almost) not the other way. 
Peak reverse volt = how much voltage you can apply in the reverse direction without it breaking down and conducting. 
rectified current = current that it is designed to carry,  over that and it probaly will overheat and burnout.
Forward volt drop = when conducting in the correct direction you will get this amount of volts drop due to resistance.
reverse leakage at PRV = that amount of current that will leak when you apply the reverse voltage. 100 microamps in this case. 
  You can get different ratings for all of these things.  Mostly need to be sure that PRV and Rectified current are high enough for the application.  In this case 50 volts is way more that the 24-48 you'll have, and 25 amps is more than you'll be running through it.


There are four connections on a full wave bridge.  Two are the AC connections, doesn't make any difference which wire goes on which connection.  The others, marked (+) and (-) are the DC ones and the appropriate polarity DC wires should be wired to them. 
« Last Edit: September 03, 2006, 06:54:25 PM by bitsnpieces1 »
Lister Petter AC1, Listeroid 12/1, Briggs & Stratton ZZ, various US Mil. surplus engines. Crosley (American) 4cyl marine engine(26hp).

Doug

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Re: Low voltage
« Reply #20 on: September 03, 2006, 06:56:12 PM »
I'm not a sparky I'm an elelctrican, the term sparky tends to make me think your a welder or a very unlucky electrican ).

Just a point I'd like to make about the PIV rating of diodes and bridges try and go double or a little better than the actual voltage required. This is cheap insurance that a voltage spike caused by any one of a number of things doesn't blow a diode.

Doug

dkwflight

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Re: Low voltage
« Reply #21 on: September 03, 2006, 07:17:17 PM »
Hi Sorry about the sparky crack. My mistake, I was looking at a photo by somebody who was drawing a big spark with a piece of wire from two power pole transformers powered up backwards from a 240 volt power supply. powered this way the 240 is stepped up to several thousand volts and will throw very impressive sparks. I don't remember who was doing that demo but an accident could be deadly.

And you are right, by useing a diode that has a rating higher than the source power supply you have a cushion to avoid future breakdowns.
Thanks
Dennis
« Last Edit: September 04, 2006, 02:07:38 AM by dkwflight »
28/2 powersolutions JKSon -20k gen head
Still in devlopment for 24/7 operation, 77 hours running time

Doug

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Re: Low voltage
« Reply #22 on: September 04, 2006, 12:23:29 AM »
Yes I also saw that photo and it made the hair on the back of my neck stand up. I even offered to send him a pair of 15 kV hot gloves but after reading his reply I see he seems to know what he's doing.

Arcs care the hell out of me, I have a small flash burn on my arm and I'm not eager to repeat the experince. I've had some scares working in high voltage and invariably the reasons were improper use of tools, PPE and not following the procedure. Another point often not spoken about is how hi the available falut current has become on todays power system. We now talk about things like arc blast and thermal energy at so many inchesr when we decide what level of protection we need to do a job becausea bad arcing fault can give you 3rd degree burns and metal vapour burns lungs. Arc blast, ,the presure wave caused by all that energy in a confined space and how far it likely to toss you back. As recently as Friday night I was checking the SCRs in large drive, doing a hot test on a very large machine and few people in my dept want to do that anymore out of the real fear of arcs and just how much energy is available.

And from an engineering stand point situations where you have power electronics and inductive circuts like field coil you go for a minimum of 2.5:1 margin. Many go much higher but this is the min you would wnat in a situation where some sort of inductive kick back or transient ( don't ask what kind on a machine this small I'm just talking in general ) to ensure the semicon device will servive.

Doug

Joe

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Re: Low voltage
« Reply #23 on: September 04, 2006, 12:31:17 AM »
bitsnpieces1,

Peak reverse volt 50v
rectified current   25a
Forward volt drop 1.7v
reverse leakage at PRV 100ua


In my box of diodes I have one that matches that spec exactly...it is a Radio Shack
# 276-1185..the price on it is $2.99....I have no idea how old it is or what the current price is...but the ones I bought last year on ebay were cheaper and bigger...
maybe way too much over kill?..... arrrgh... more power....

Joe

Nothing is easy...if it were...anybody could do it.

2005 Power Solutions  6/1-ST5

Doug

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Re: Low voltage
« Reply #24 on: September 04, 2006, 12:38:00 AM »
25 amps is just a tad more than your going to need, Id like to see a PIV between 100 and 200 volts just to be safe, but the lower end of that range is probaly already overkill. I have no idea wht the field current for that should be but I can't see it being much above 5-10 amps

dkwflight

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Re: Low voltage
« Reply #25 on: September 04, 2006, 02:06:55 AM »
Hi Doug
I don't know what the amps are running through the diode, I'll check tomorrow.
I would like to clean up my power. The computer UPS would not kick in and let me run my computert today.
Dennis
28/2 powersolutions JKSon -20k gen head
Still in devlopment for 24/7 operation, 77 hours running time

Rainbow-Farm

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Re: Low voltage
« Reply #26 on: September 09, 2006, 10:45:23 PM »
Has anyone ever tried an APC Line-R for voltage regulation after the generator? They are made in 300, 600, and 1200 watt. I suspect they are full of copper... they boost low voltage and clip high voltage... "melt" for lightning protection.

Might be good for stuff like computers, UPS, etc... give the appliance cleaner juice, maybe partially or fully overcome fluctuations from the generator?

I bought 3 of them and use them, even with grid power. I don't notice any difference but them I have never tried them on  generator power yet.
Do not trust the "grid" folks!

dkwflight

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Re: Low voltage
« Reply #27 on: September 19, 2006, 01:18:47 AM »
Hi I bought the APC Line-R power conditioner. hoping to be able to run my pc off generated power. No Luck at all!
It didn't make any difference to the UPC. It still acts like there is no power present.
Dennis
28/2 powersolutions JKSon -20k gen head
Still in devlopment for 24/7 operation, 77 hours running time

peterako

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Re: Low voltage
« Reply #28 on: September 19, 2006, 08:05:30 PM »
Hi oke i am a sparky :P

Check your label on the gen. the field voltage and current are the ones you need.
always use bigger bridge rectiferers or install two two lower the loses and heat in the units.

Keep in mind the most off the cin. and indi. types are not so good. replace a.s.a.p.

also lower heat on the diodes means more current and voltage to the field coil means more magnetic field means more power.

yes it is another inprovment on fuel here and cheap.

greetings from Greece  ;D
lovson 6/1 DI backup for my new house using solar heating and power plus a 1000W wind generator.