Author Topic: Diode, Placement? (Read 6648 times)

coldspot · « **on:** January 09, 2006, 05:50:45 PM »

Diode, Placement, On a DC Motor?

I am ready to restand my tower and Ametek 30 VDC minimill.

I am wondering about the diode placement, UP by mill or DOWN in by Charge Controller?

Also, I have salvaged a bunch from other failed electronics.

I have, (in the larger physical sized ones), "SD945", "RK44 4D", "MW MR 504 8408","G1504 8332", a pair mnted together on aluminum, NEG(side away from stripe?) side heatsink/conductor 1/4" x 2.5" marked "EGP30DG18641" and one with a RED not silver color stripe and markings, "RG4Z 41".

Anybody with bettter/experience info, please advise on what one and where.

How big a heat sink will be needed, I'll use old cpu sinks and thermo paste.

And a side thought, I've used the little glass ones on stepper motors also some of the smaller, (little black ones with silver markings), "IN4007 GI 432". to get DC out.

Once I've got control box set-up, (Box with charge controller, Battery isolater and fuses in it), I should be able to just run all these steppers into an POWER IN line from outside to the control box and get the little extra power also with out many issues.

I know I should Goggle but I am buzy with running lines and Tower placement, Guy lines ect...

I'll check back after shower and will be ready for tower restanding, but would like to know if Diode should be placed up there or not.

THANKS, I love to surf this site!!!!!!

l8r

drdongle · « **Reply #1 on:** January 09, 2006, 01:56:18 PM »

Put it Down tower, simpler to repace that way.

Flux · « **Reply #2 on:** January 09, 2006, 01:57:43 PM »

It really doesn't matter but it seems so much simpler to have it where you can get at it and where the environment is friendlier to it. I would put it near the battery.

mlz · « **Reply #3 on:** January 10, 2006, 08:15:45 AM »

I'd place down the tower, IIRC, there are less line losses with AC over DC. Plus the obvious advantage of having it handy when you blow a diode.

Speaking of which, I'm thinking of building two arrays with knife switches, so that I can cut them in and out in case of one or more frying and allowing the system to unload in a high wind.

ghurd · « **Reply #4 on:** January 10, 2006, 08:30:53 AM »

And where the enviroment is friendlier to the meters, soldering iron, and maintaince person (you).

Repairs around here seem to need done when it is 33'F in a driving rain.

G-

coldspot · « **Reply #5 on:** January 10, 2006, 11:46:53 AM »

OK

So NOT up the tower.

Cool will be easy that way, so they do blow out sometimes then?

I put the tower back together yesterday and running down wire thru it was a major pain,

kept hanging up on cross bolts, was about 3' from bottom and stopped. Had to get girlfriends son to wiggle the wire at top side, (tower laying down in hallway with top end resting across a couple of fold-up dinner stands n bottom held up by legs opened), while I ran a wooden arrowshaft dowl with paper clip rubber banded to end hook style to finally get it to drop thru to bottom end, MAN that was a pain! lol.

Tower now be about 12' n girlfriend worry about power lines out back. Will be hard to please her about my "Hobby" stuff. lol

Anyway

THANKS for replies!!!

l8r

richhagen · « **Reply #6 on:** January 10, 2006, 04:01:12 PM »

As a minor consideration, the rectifiers are going to radiate a small amount of heat. A half volt voltage drop at 10 amps is 5 watts worth. If it were a large wind turbine, that heat might be more considerable in windy weather. If the mill were using a full bridge rectifier, the voltage drop would be one to one point two volts under load, and If you draw fifty amps at one point two volts, you would need to radiate 60 watts of heat. Thats good in the winter, not so good in the summer if it is inside I guess. Anyway, while not a major consideration, it is interesting. Rich Hagen

richhagen · « **Reply #7 on:** January 10, 2006, 05:45:12 PM »

They often fail to short, which is not necessarily a good thing since that can connect the battery straight to the coils in your mill, turning them into a heating element.

http://www.fieldlines.com/story/2005/7/23/23160/8453 (rectifiers failing to short)

http://www.fieldlines.com/story/2004/10/25/101453/25 (rectifiers overheating)

http://www.fieldlines.com/story/2004/12/10/144656/52 (heat from rectifiers)

While you could put an overcurrent fuse, such as in Tim's power panel:

http://www.fieldlines.com/story/2004/10/18/131136/07

If that fuse or circuit breaker blew you would have an open circuit and since this would most likely happen in in windy weather, you would then risk your mill flying apart since it would likely overspeed with no load on it. If you are around at the time and catch it, you could disconnect the rectifiers and short the mill to stop it. On the panel in the example, you could disconnect the rectifiers and throw the switch on the AC side to short out the mill. If you are not around, you will likely at best need a new stator I would think. All in all, I think risking a cooked stator on the mill would be more attractive to me than having a fire in my house. I can always make a new stator or blades.

It strikes me that a little planning here can help prevent a potential fire risk and minimize damage in the event of a failure. Automating a control circuit to handle a situation where the rectifiers failed to short, but which draws no or little current otherwise would be an intersting project. It would have to detect a failure, and then open the battery circuit between the batteries and the rectifier and short the alternator. Rich

kenputer · « **Reply #8 on:** January 10, 2006, 06:10:57 PM »

Just a tip on fishing wire,get out the shop vac and some twine,tie a small piece of rag to the twine put the vac hose on one end of pipe and go hold rag and twine at the other,let the suction pull the twine through, tie wires on twine and pull wires through. Works like a charm.

Kenputer

TomW · « **Reply #9 on:** January 10, 2006, 07:51:03 PM »

kenputer;

Yes, sucking light line thru conduit is a neat trick. I use that tarred net making line very tuff stuff. Seems to work on long runs too over 200 feet.

Cheers.

TomW

coldspot · « **Reply #10 on:** January 11, 2006, 05:06:18 PM »

Yea a vac would have worked but,

with 12' I did'nt want to drive across town for "FishTape" in my storage toolbox.

It would have went easyer if I wasn't using two extention cords hooked together,

wire ties kept hanging on cross bolts.

Thanks for all the input anyway!!!

All this info on rectfiers has given me a better idea of how much heatsink will be required when I build a dual rotor. BUT,

How much is required for the Diode on this Ametek 30 V DC PM Motor???

ghurd · « **Reply #11 on:** January 11, 2006, 07:14:08 PM »

I will suggest the overkill approach.

Maybe feed the gennie's positive into both AC ~ terminals of a 25A bridge. Output is still the positive terminal. Easy to heatsink a bridge too.

G-

kenputer · « **Reply #12 on:** January 12, 2006, 05:32:57 AM »

I use a 40 amp diode (free) on my ametek motors down at the batteries with a 50amp dc on/off/on switch to shut it down if needed.

coldspot · « **Reply #13 on:** January 12, 2006, 12:46:18 PM »

Overkill- Thats my normal way also.

But, of all the Diodes I listed above, only one shows on a search-

SD945, 9A, 340V Forward, 45V reverce.

Bat= 12 VDC, so using W=VI, 12X9=108, Would this then be good for 108 Watts? seems wrong.

I also have some rectifiers but was going to save for use when I get to a dual rotor.

But, as I have 4 PM motors, I quess I'll use one now, for first one UP.

one is a "tympanium corp" 278000123 2300, square shape center hole.

one 27 H Q-OA, raised numbers on it 511938 with a 2 by one mnt hole.

one 19 I Q-OA, " " 511938 with 3 by same hole. These are round w/two mnt tabs

Those three are aluminum body, and I am pretty sure for Outboard motors.

also one 369450 1 1397 rec shape plastic body potted bottom, rated at 20Amp, (marks I made a long time ago).

Also one "Diode Rectifier" it has three diodes "ZP IN 5402 9707", I think it was inboard motor.

So I quess I should use one that can be mnted to Heatsink, should all three "In" wire put but on Pos side of gen then? Or could I only use one and as I get more PM gens UP, use the other wires for their Pos.

The chargecontroller, "FlexCharge NC25A-12", is only rated at 25Amp 12 VDC.

Sorry for all the crazy questions but thats why we are here, to share.

THANKS

coldspot · « **Reply #14 on:** January 12, 2006, 12:51:20 PM »

OOP'S-

All three aluminum Rec's have three IN wires and one out wire.

ghurd · « **Reply #15 on:** January 12, 2006, 03:50:56 PM »

The forward voltage should never go past 2V. Something is very wrong if the forward voltage is past 1.0V per diode.

I personally believe a higher If and Vr result in a lower Vf (loss).

I never saw a 4 pin 'diode', except for monster 3-phase units used in steel mills. 3 pin diodes are usually dual diodes, like half of a bridge rectifier.

Anyway, IMHO, go for the biggest amps first, then over 50Vr.

dinges · « **Reply #16 on:** January 12, 2006, 04:01:59 PM »

Thanks for the tip!

Had never heard of this one before, but now you mention it... Sound so logical and easy, I should have thought about this myself.

The things you learn on this board....

Peter,

The Netherlands.

ghurd · « **Reply #17 on:** January 12, 2006, 04:12:57 PM »

And a toy crossbow pistol will send kite string and bolt / arrow very far, allowing a stronger string, then pull wires through a wall or ceiling. Scares the crap out of rodents, marsupials, etc, too. Big fun!

dinges · « **Reply #18 on:** January 13, 2006, 09:52:02 AM »

Spot the contradiction in terms:

toy crossbow

Now, if I had a toy crossbow, I wouldn't scare the little critters, I would get me some meat.

Peter,

The Netherlands.

coldspot · « **Reply #19 on:** January 13, 2006, 12:16:35 PM »

"Toy CrossBow"

Now thats one I didn't think about, might be good Idea.

But Having a couple of them and many experiences with them, (CrossBows)

I'm pretty sure that the string would break, (having broken fishingline up to 20Lbs and also the braided Hi-Tech stuff up to 50Lbs, But that is probebly because MY BOWS are tweeked to 80Lbs and 115Lbs pull, {I can't leave stuff stock}, so maybe if tried with regular bow just lightly pulled would WORK GREAT).

And as Pete said-

The stuff we learn here is just great!!!!! THANKS

coldspot · « **Reply #20 on:** January 13, 2006, 12:21:56 PM »

The diodes are standard, one in one out

the rec's are from the boating industry, inboards and outboards.

coldspot · « **Reply #21 on:** January 18, 2006, 02:45:41 AM »

OK

I came up with

MUR3020PT, (Mosfet looking 3 leg unit 15A per leg, the two outside ones)

ESAE83-004, (same 3 leg type unit, rated 60A ?)

also a

RBV-404, (4 leg unit with sine marks on center legs and + left leg with - right leg)

But even looking over the "datasheet" I can't tell if 4 Amp or 80 Amp.

If(AV)(A)With heatsink 4.0

Ifsm(A)(50Hz)Half-cycle Sinewave Single Shot 80

Also marked on it under the "RBV-404" is "53 A"

This might make a good bridge Rec for a AC unit but I'm still on a Ametek 30 V DC

So if I use the E83-004 or 3020PT, They are showing bolth outside legs as "IN" and center leg as "OUT", A PM DC Motor Has a Pos, (hot) and a Neg Wire.

I know this is a stupid question but

Should I only use one "IN" leg or bolth by splitting the hot (pos) wire to them???

Or by only using one, could I hook up an other miniGen later on the other "IN" leg???

ghurd · « **Reply #22 on:** January 18, 2006, 07:19:19 AM »

Use both legs, and a big heat sink.

With good luck the 15A will be too small for a good derated design. Seems like most people report 5 to 8 amps peak? It's good for 5A, but I wouldn't use it for 8A.

The bridge sounds like a 4A unit. Too small.

You will find another big dual diode, or bridge before the next gen is ready.

Also, pos and neg will depend on the direction of rotation, not the wire color. But you knew that.

"May the 15A dual diode burn out!" (Good Luck)

G-

coldspot · « **Reply #23 on:** January 18, 2006, 11:37:26 AM »

GHURD-

THANK YOU!!!!!!!!!!!

" not the wire color"

Yea I'm using brown and white, (all the Dollar store had left after X-Mas in extention cords) for the down in tower, (16G used bolth wire for each leg), then an outdoor rated extention cord 100' from a friend will be used for in to the control box, (also had white n brown wires inside, LOL).

I can't see these tiny rec's being able to handle any REAL power.

Pic from this morning.

Wouldn't any one of these be much better for the job???

The black one is new as is the square unit.

bolth round ones are used.

This is the one I'd rather use, With a heatsink.

Wire bolth yellows to Pos and just forget about the black one?

ghurd · « **Reply #24 on:** January 18, 2006, 12:18:28 PM »

"Wire bolth yellows to Pos and just forget about the black one?" Yes.

ghurd · « **Reply #25 on:** January 20, 2006, 07:23:41 AM »

I just read a story about a guy getting 17 amps from an Ametek. Looked a little deeper and found a few more people claiming well over 150W. Sorry.

The 15A bridge is going to be marginal. Keep an eye out for a bigger unit.

News:

Author Topic: Diode, Placement? (Read 6648 times)