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me,my stator and a brick wall
By spinner, Section Homebrewed Electricity Posted on Wed Mar 15, 2006 at 03:27:02 PM MST
the soultion seems too elusive for me

I have been experimenting with a 9/12 machine on and off for a few weeks, time permitting.
My delima arose when I tried a jerryrig to see what the outcome might be.The stator unit was built before jerryrig but I just wanted to learn a little via experimentation.
In a nutshell: each phase is putting out ok ac loaded or unloaded within acceptable limits for the machine.
What I do not understand is how I can have that ac to each rectifier(3) but only decimal point DC output from the rectifier(s ) individually or as a group/checked both ways... into a 2.4 ohm load (verified with a battery)-thanks for the tip, flux....and it matters not if the load is hooked to the rectifier (s) or not.
.Example...which has been doubble checked: @5volts ac in I will have perhaps .4dc out with NO amperage I can measure into the load.
I have not run the output up past 8v ac this time around because I don't know why I am having a problem.
I have not checked each rectifier on this go-round to see if one or more is bad, because they are all brand new and have been protected by fuses of a much smaller amperage than their rating ( cautious because I already lost one set ).
If it turns out that no fault lies in either the stator coils or the stator connections
I'm gonna find myself otta bullets!
I have the unit apart now..checking for any connection problems etc. so far everything seems ok.
I presume this is yet another case of me missing the obvious
which is why I'm asking questions now
thanx
spinner

me,my stator and a brick wall | 24 comments (24 topical)

Re: me,my stator and a brick wall (3.00 / 0) (#1)
by TomW on Wed Mar 15, 2006 at 08:49:30 AM MST

spinner;

I am going to take a wild guess that you are using bridge rectifiers and you have them connected wrong.

It is easy to miswire those square bridges with the spade connectors. Your symptoms lead me to believe thats the issue. I could be wrong, of course.

Cheers.

TomW

The Truth is the Truth, even if no one believes it; and a lie is a lie even if everyone believes it

Re: me,my stator and a brick wall (3.00 / 0) (#2)
by Flux on Wed Mar 15, 2006 at 09:11:08 AM MST

You may be right Tom. I couldn't quite follow what he is doing. If there is resistance to turning then it is obviously connected wrong. Otherwise each bridge should give a dc output. Check silly things like having the meter on dc and not ac. Also check those fuses to see if you have blown them.

Difficult to do this by telepathy, much easier with the thing on the bench and all information available.
Flux

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#4)
by spinner on Wed Mar 15, 2006 at 04:32:58 PM MST

hmm

i put it back together again and it acts exactly the same,ie each group of coils (phase) on the gen is hooked to two ac terminals on a rectifier.

The AC output from the genny is present on each rectifiers ac terminals, it is pretty much the same for each individual rectifier: ac voltage rises nicely as the machine accelerates BUT there is only a decimal number when dc output is measured from the -,+ terminals of any individual rectifier.

There is one wire from the "start" coil of each phase and one from "finish" coil of each phase to each individual rectifiers' ac connections .

I should also add that when I run the machine in either conventional Y or Delta mode it appears to operate as it should.

As far as I can tell the only difference is that I am using a different set of rectifiers for the conventional hookups and, ov course there are jumpers involved with winding hookup in y or delta that are not in the Jerry rig

gonna go poke around some more (and check rectifiers/fuses again

thanx
spinner

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#8)
by spinner on Wed Mar 15, 2006 at 06:26:56 PM MST

hiya Tom

when I made up the little thingy to hold the 3 individual rectifiers I did so making sure the DC _ and + points were all facing the same way

also double checked that, too

whole thing makes no sense to me
thanx
spinner

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#3)
by Gary D on Wed Mar 15, 2006 at 10:24:10 AM MST

Could it be as simple as not having the start and end of each phase hooked to the same rectifier to complete the circuit? Six wires out of stator?

Re: me,my stator and a brick wall (3.00 / 0) (#6)
by spinner on Wed Mar 15, 2006 at 06:11:23 PM MST

gary
yep ..double checked it...again
thanx
spinner

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#5)
by drdongle on Wed Mar 15, 2006 at 05:23:52 PM MST

Are you sure that your meter is working correctly on DC volts?
Carpe Vigor, Dr.D

Re: me,my stator and a brick wall (3.00 / 0) (#7)
by spinner on Wed Mar 15, 2006 at 06:23:53 PM MST

drD
thanx
yep it works ok
fact is: when I switch out the wiring and reconnect the genny either as a conventional Y or a conventional Delta into a three phase rectifier setup all is well.

I used the jerryrig hookup that he had posted awhile back: 6 wires from the genny ( 2 per phase, to each seperate rectifiers AC connection points) then tied all three rectifiers DC+ leads together and all three DC- leads together, then to the load after going thru a fuse for each.(with or without a load..doesn't matter/ checking DC from the common connection DC- and DC+ AT the rectifier (s) always indicates only a decimal (less than 1 ) voltage output even with 8v ac into each individual rectifier, from the genny
thanx
spinner

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#9)
by Gary D on Wed Mar 15, 2006 at 07:43:35 PM MST

Spinner, the only thing that I can think of is for the "Jerryrig" setup you should be seeing about half the voltage. That's if the turns per phase weren't increased for the same speed, compared to star.
I've read on this board that many meters dislike the low frequency and the readings are squirrely at low rpm's.
I definately am not an expert by any stretch (or dream). Just an interested observer... If you can figure things out, I think some might be interested in your findings other than me? Gary D.

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#12)
by spinner on Thu Mar 16, 2006 at 06:46:09 AM MST

hiya gary

forgot about the low frequency/digital meter thing til I saw your post this morning

if I am reading 5v ac accross the rectifier input lugs I will see around .5 to .10 across the DC- and DC+ of that rectifier.........tried several rectifiers: same result

thanx
spinner

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#10)
by Ungrounded Lightning Rod on Wed Mar 15, 2006 at 08:30:40 PM MST

You can connect it like this:

- Wire it "jerry". Tie the rectifiers together and + and - and use a single fuse, then don't bother to sort out pairs and match them to a particular bridge. (In fact it's better to pair the ones that would be tied in delta - see below.)

- Make a Y by switching on a short among the three coil terminals that would be connected together at the center WITHOUT disconnecting them from the AC terminals of the rectifiers. (They'll never be at a volatage above the + or below the - anyhow.)

- Similarly, make a delta by switching on a short between the same three wires individually and the three they'd connect to in delta, again without disconnecting them from the rectifiers. (Now the two sides of the bridge are paralleled - and they match better if you use the same bridge for both halves, minimizing mismatch due to operating temperature and diode manufacturing tolerances.)

Start with delta. Turn off the delta shorts and output current should drop but unloaded voltage should remain the same. Then switch on the Y shorts and unloaded voltage should rise to 1.732ish (sqrt(3)) times the previous value.

With no load the genny should turn freely in all but the delta configuration, and should only have slight "fluid friction" resistance in that config. If it has high resistance in the delta config you've got a coil's ends swapped. (That would also reduce the output current from the Y config but not affect peak voltage, though the waveform might confuse the meter a bit and make it read lower.)

You ARE using an analog meter for this due to the low frequency, right? (Digital meters can get pathological at low frequencies.)

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#11)
by Ungrounded Lightning Rod on Wed Mar 15, 2006 at 08:32:39 PM MST

Tie the rectifiers together and + and - and use a single fuse ...

Should read: "Tie the rectifiers together AT + and - and use a single fuse ..."

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#15)
by spinner on Thu Mar 16, 2006 at 10:39:08 AM MST

update

I quickly discovered that, when hand spinning the genny, it begain to become harder and harder to turn as soon I connected to the rectifiers ( even tho they were not connected to a load...to a lesser degree the same can be said for delta jumpers as well.

noting this, I cannot help but wonder if my stator is all or in part at fault.

this stator is composed of 9, 2inhand coils that are potted into the stator.
physically, two leads come out above the stator and two below it; I checked each coil to detirmine which lead on the top went with a bottom one and marked them for identification.

I then wired each coil in INTERNAL series ( each coil has 3 studs by it: one for "in", from the bottom and one for "out" on the top outside edge of the stator; the third stud is a connection point for the other two ( 1 from the top and one from the bottom )wires so that the coil is hooked in INTERNAL series, winding wise, but can easily be changed to parallel if more amps are required/desired by me.

I double checked each coil and they are all hooked up the same, but I now wonder if, somehow, the jerryrig hookup and to a lesser degree, perhaps, the standard 3 phase delta hookup is causing my problem...seems remote, but I did say I was stumped, right?

I should note that when tested individually, voltage across the coil when it is INTERNAL series is double what it is if I hook the coil up like a regular 2inhand (paralled windings).

Since the unit does seem to work fine in standard Y or any combination of individual coils being made parallel instead of series INTERNAL, I did not think of it as a potential problem.

I just ain't smart eneough to see the soultion
thanx
spinner

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#17)
by Flux on Thu Mar 16, 2006 at 10:51:51 AM MST

update
I quickly discovered that, when hand spinning the genny, it begain to become harder and harder to turn as soon I connected to the rectifiers ( even tho they were not connected to a load...to a lesser degree the same can be said for delta jumpers as well.

There's your answer, try with each rectifier alone. Any that causes it to load up without a load is duff. Adding a working rectifier with no dc connection should make absolutely no difference to load or ac voltage.
Flux

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#24)
by Ungrounded Lightning Rod on Fri Mar 17, 2006 at 09:05:34 PM MST

In particular, it looks like either one or more of the diodes is shorted or there's a mismarking of which terminals are AC.

Try this:

Try the following tests on each bridge with a meter set on "diode test" (if you have it) or a mid-to-high-range ohms scale otherwise. ("open circuit" is more than a megohm):

First unhook the load and the coils, and tie all the AC terminals together. Then test:

- Red to +, Black to the AC terminals. (Should show continuity.)
- Black to +, Red to the AC terminals. (Should show open circuit.)
- Red to -, Black to the AC terminals. (Should show open circuit.)
- Black to -, Red to the AC terminals. (Should show continuity.)

Depending on your meter, the tests that show continuity and those that show open circuit MIGHT be swapped. The important point is that they should be either as above or ALL the "open" and "continuity" readings are swapped.

If you get anything else you've got one or more bad diodes in the bridges. So it's time to isolate them:

Unhook the bridges completely. First a quick test:

- Red to one AC terminal, Black to the other. (Should show open circuit.)
- Swap Red and Black. (Should still show open circuit.)

If you show any continuity that bridge is defective. Continuing:

- Red to +, Black to each AC terminal in turn. (Should show continuity.)
- Black to +, Red to each AC terminal in turn. (Should show open circuit.)
- Red to -, Black to each AC terminal in turn. (Should show open circuit.)
- Black to -, Red to each AC terminal in turn. (Should show continuity.)

Again the "open" and "continuity" readings might be COMPLETELY swapped. Also: All three the "continuity" readings should be in the same ballpark.

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#13)
by spinner on Thu Mar 16, 2006 at 07:01:14 AM MST

hiya

nope, not using an analog meter at theis point in time, only have a digital.

I am gonna go and try your suggested procedure (before I pull out the rest of my thinning hair *G ) and will post the results.

what is confusing me most is the fact that I always get the same AC readings per phase into an individual rectifier ( when their DC outputs are not connected together) and the same miniscule DC readings out...same case when I have the rectifiers all tied together @ their DC- and DC + points

for example: AC into an individual rectifier from any phase on the genny= 5v, while the DC reads somewhere around ( if I recall correctly ) .10 DC............matters not loaded or unloaded, nor which rectifier (s) I substitute

thanx
spinner

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#14)
by Flux on Thu Mar 16, 2006 at 07:10:45 AM MST

Spinner
Try without meters. Firstly short an ac pair and make sure it is hard and lumpy to turn. If so connect a bridge to that pair and short the dc side of the bridge. It should need a bit more speed to load up but it should again become hard and lumpy.

If not the bridge is duff. If it now loads up with a short on the dc side and runs free without the short you have a meter problem.
Flux

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#16)
by spinner on Thu Mar 16, 2006 at 10:49:56 AM MST

hiya flux

checked my meter against a known dc source this am...seems fine
will try the test anyhoo, cause it mite shed some lite on the matter; seems like a good next step.

I ans. a post a few moments ago from another helpful individual reguarding my stator and how it MIGHT be part of the problem when connected up jerryrig or to a lesser degree delta, tho I cannot see how, given that the damn thing seems to work fine in Y or my own version of modified Y

thanx
spinner

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#18)
by spinner on Thu Mar 16, 2006 at 12:04:49 PM MST

flux
it seems that the rectifiers are not the problem either

thanx
spinner

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#19)
by Flux on Fri Mar 17, 2006 at 01:00:22 AM MST

I think I have finally seen what you are trying to do.

"I then wired each coil in INTERNAL series ( each coil has 3 studs by it: one for "in", from the bottom and one for "out" on the top outside edge of the stator; the third stud is a connection point for the other two ( 1 from the top and one from the bottom )wires so that the coil is hooked in INTERNAL series, winding wise, but can easily be changed to parallel if more amps are required/desired by me."

If you have connected those two sections permanently in series you must ignore the connection in the middle and treat the thing as a coil with 2 ends.

You can't connect those coils in parallel in the way that you may be trying. You would need to break the center connection and reverse the phase of one coil.

There is a way round it by making it into a bi phase rectifier but you are confused enough already and any new ideas will make things worse.

Regard those coils as what you call internal series and just treat them as a coil with 2 ends and things should work.
Flux

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#20)
by spinner on Fri Mar 17, 2006 at 06:40:01 AM MST

greetings flux
and thanks for your continued efforts to help!

actually, i only mentioned the somewhat offbeat configuration of this stator because I thought that, possibly, in some way i had failed to see, it was contributing to my delima....sorta grasping at straws, i suppose.

i will go thru yet another exploratory test series again today tho i expect i have stumbled into an impasse as far as making it work jerryrig which might ultimately require more torque than my dualhelix will handle properly anyway ( I have not aquired torque data to prove that, just a suspicion at this point )

oh, by the way...a young friend of mine dropped off a whole bunch of goodies the other nite including a couple of dc torque motors with splined shafts that have either sensor or encoder wires comming out as well as the power wires ...have not had the time to ascertain which, as yet...too busy trying to figure out this problem!
if they might be of use to you or someone else here it'll maybe be "swap time" or whatever works??????? somebody here is always looking for something perhaps for a cnc machine or a bridgeport...i didn't pay anything for 'em, don't know if/how good they are so I don't wanna accidently sell somebody somethin' that ain't what it otta be

thanx again
spinner

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#21)
by spinner on Fri Mar 17, 2006 at 09:28:15 AM MST

PS
I should have mentioned that the coils are hooked up ( subject to finding an efficient way to reconnect internally from series to parallel )on demand.

all my posted info on the subject has been with the coils hooked up in INTERAL series via the third post for setup.

thought I otta clarify
thanx
spinner

[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#22)
by drdongle on Fri Mar 17, 2006 at 03:29:08 PM MST

Can you give us a schematic of your hook up?
Carpe Vigor, Dr.D
[ Parent ]

Re: me,my stator and a brick wall (3.00 / 0) (#23)
by spinner on Fri Mar 17, 2006 at 07:45:39 PM MST

DRD
i will have a go at it, not much of an artist (or genny builder either, I guess )

the sketch is of one coil but all 9 in the stator are done the same;
should be in my user file as "stator-x"

[ Parent ]

me,my stator and a brick wall | 24 comments (24 topical)

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