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diode for collapsing magnetic field

Discussion in 'General Electronics Discussion' started by Blank Stare, Oct 10, 2012.

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  1. The Electrician

    The Electrician

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    Jul 6, 2012
    Put an ammeter in place of the burned out diode and see what current is flowing. Maybe use an ammeter that can measure up to 20 amps. Then track down where the current is going. Is it in the green wire going to #30, the relay? Maybe the relay coil is shorted. Is it going through the green wire labeled as going to the manual switch. Maybe something is wrong over there.

    At any rate, use standard troubleshooting techniques to see where the current is going.. Once you know that you can figure out why.
     
  2. duke37

    duke37

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    Jan 9, 2011
    An old trick is to put a bulb in the circuit to limit the fault current.
    Replace your diode with a new one which is in series with a bulb, you can then tell if the current is excessive.
     
  3. The Electrician

    The Electrician

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    Jul 6, 2012
    Did we lose Blank Stare?
     
  4. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    Yes, I too need closure. :)

    Chris
     
  5. Blank Stare

    Blank Stare

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    Oct 10, 2012
    Not gone, just damaged. :(

    Ripped the tendons that attach the bicep to the forearm. Haven't been able to get under the hood one-armed, and with this long cast on, typing is an arduous, and somewhat painful task.

    Didn't forget ya - after all, I made a promise.

    But it will be at least 8 weeks before I have enough use of my left arm, to even consider stripping wires, and checking circuits.

    Just a note...I think I reversed a wire on the relay, when I replaced the old one. I have since purchased a relay "Socket" to make sure that doesn't happen again.

    Anyway, I'll be back as soon as my wounded wing lets me.

    ~ Blank Stare
     
  6. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    Ouch! Very sorry to hear that. How did it happen?

    Chris
     
  7. Blank Stare

    Blank Stare

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    Oct 10, 2012
    Been in the trades my whole life - so carrying heavy stuff has been a normal part of my life, as far back as I can remember.

    I picked up a table that I had removed the legs from, holding it on my left side, from the bottom, top side guided by my right side. Done this a thousand times with windows, drywall, plywood, shingles, glass panels, you name it.

    This time, I felt what was similar to guitar strings breaking, one at a time in quick succession. Or, you could compare it to putting rubber bands between the fingers on both hands, and pulling until they break....

    The Doctor drilled a hole through one of my forearm bones, then pulled the tendon back through it, and put some kind of "clip" on it, to keep it in the bone.

    I'll probably be "one-armed" until spring. They are planning a "moving" cast in a few weeks, but I get the impression that it is designed to severely limit the range of motion.

    Anyways, when I am back in action, one of my first projects is to get that system working again.

    Thanks for the well-wishes,

    ~ Blank Stare
     
  8. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    Well there you have it. One day we all wake up doing what we always did and Wham!! Machines wear out and so do we. ;)

    Get well soon.

    Chris
     
  9. Blank Stare

    Blank Stare

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    Oct 10, 2012
    The moving cast is more of a "brace" than a cast.
    It does restrict movement somewhat, but nowhere near like I thought it would.

    Anyone else from the midwest?
    Do you still have both butt cheeks?
    We about froze ours off this past week, with daytime temps sometimes in the single digits! :eek:

    Anyways, since the surgery, I have conveniently (or rather, not so conveniently) misplaced the 1n5378 diodes that I bought, along with the 1n4001 diodes.
    (Before I put them away, I made sure to train them to wait until I had ordered more, and completed the project, before they showed up again... :rolleyes: )

    I have the 1n4001's on order on ebay. I am looking for the 1n5378, but everywhere I look has a different suffix, such as 1n5378B, or 1n5378BLRG, etc. (I'd order them from mouser again, but the $5.00 shipping fee for something that fits in a first class envelope offends my sensibilities...)

    Can I use, "1N5378B Manu:N/A Encapsulation: DO-201,5 WATT ZENER REGULATOR DIODES 3.3-200 VOLTS" ?
    If so, I think I am off to the races...

    Once I'm sure what to order, I'll have all the parts to finish with the changes we have discussed/designed during this discussion.

    Watch for an update in the next several weeks.

    ~ Blank Stare
     
  10. CocaCola

    CocaCola

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    Apr 7, 2012
    I hate the cold but born and raised in the area and if I'm prepared I can rough it out... I was auging out our sewer drain outside the other night it was a whopping 1° F with a windchill of -10° F, fun job, NOT... The worst part is that the water was freezing on the equipment near instantly same with my gloves, they were icing over in and instant, so instead of leather gloves I had rock hard, slippery ice gloves that made it that much more fun... Oh well, gotta do what you gotta do sometimes, more annoyed that the cold was freezing up the water on everything then actually being or feeling cold...

    Suffix should not matter much, it's usually a temp or environmental rating and for general use not a big issue...
     
  11. Blank Stare

    Blank Stare

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    Oct 10, 2012
    Have had similar experiences, but never one so "In your face" as that one".

    Excellent, I will get them ordered, and start getting this project on it's way again.

    ~ Blank Stare
     
  12. Blank Stare

    Blank Stare

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    Oct 10, 2012
    I finally have the casts and brace off of my arm. I still wear the brace part-time, but I am no longer limited to right-hand-only operations. :)

    YAY!!

    My parts are all here, and I have assembled the diode/zener diode, with connectors on each end, for easy install.

    I still have a bit of tinkering to get the wires all sorted out, and make sure the relay socket is wired correctly. When it is, the diode/zener will be an easy remove/install, in case I screw something up again. :eek:

    The forecast is for 3" to 6" of snow between now and Saturday, but the weekend looks pretty pleasant for February. With a little luck, I'll be back in operation, and then I can chase down some air leaks. (tubing comes loose when you drive through the woods on two-tracks, and across fallow corn fields.) ;)

    I am hopeful and enthusiastic.

    I'll check back in later.

    ~ Blank Stare
     
  13. Merlin3189

    Merlin3189

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    Aug 4, 2011
    What an interesting thread, though it's taken a long time to read all 18 pages and follow up the links. It's amazing how you can think you know quite a lot about a subject until you meet a topic like this. I have not only learnt things I did not know (thanks esp. to Electrician's lnks) but also come to realise that there are more issues here that I still don't fully understand. Which is one of the great things about this site, the way it provokes me to question my own knowledge and assumptions, and to dig a little deeper.

    It's also been a great thread for no one dismissing or disparaging other contributors. No one really knew the answers, everyone gave their best ideas and all were respected and discussed or constructively criticised. And you do seem to have reached a working solution. It almost restores one's faith in web forums!

    Maybe you noticed a slightly sceptical tone there? Early on I found myself with CDrive, thinking, this don't make sense. Even now I can't help feeling that, it may be working now, but we never worked out why it went wrong in the first place. Now I work in computer support, and I often find that I can 'fix' a problem, in the sense of making it do what someone wants, without actually knowing why it wasn't working in the first place. The standard "just shutdown & reboot" ,that most people use all the time, is exactly this. But sometimes it just keeps coming back until you find the cause and deal with it.
    Maybe you did and I hope so. But on top of the issues raised by CDrive, I think that:-

    DC motors interrupt the current 100's even 1000's of times a second in the normal course of their operation. There is sparking at the brushes, but they don't die quickly. Most have small capacitors to suppress RFI, but I've not noticed diodes, MOVs , etc commonly.

    DC motors have coils so I agree there's inductance around. I haven't find much detailed info about this yet, but my feeling is, it must be small. It is the nature of brushed DC motors that each winding is energised and deenergised many (1000 +) times a second. Inductance resists changes of current, so designers will want to minimise it. If inductive energy is dumped into suppression circuitry, this is a waste of energy and a limit to the efficiency of the motor, which they will want to avoid.

    Looking back I'm not clear whether this motor had been working ok at one time. But if it had, why stop now? If it worked without diodes, etc , why does it need them now? Sure they may help prolong the life, but if the system was designed and worked without them, then something else must have caused the sudden catastrophic failures.

    In my own limited experience of big motor problems (and these were AC) the failure was at switch on, due to the large surge current (which people have also mentioned here.) Now if inductance were the main factor here, I would expect it to limit the switch on surge rather than increase it. Looking at switchgear design for large DC motors, the switch on surge seems to be the main consideration - limited by a gradual or stepped reducing resistance.


    In no way do I want to criticise all the great ideas people have had working through this problem in real time. Just thought even as a latecomer, I would add my two pennorth.

    Finally, might I just ask just out of curiosity, where is the bottom right quadrant of the mitten? I'm guessing Rochester, Minnesota, but can't find any references. I think I've solved the Ronne Ice/ Peking one. I assumed short path, but I think long path could put him in Canada rather than Aus.

    Regards to all posters and esp. Blank for his persistence. Don.
     
  14. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    Don, you have a writing style that's quite enjoyable to read. There wasn't a single sentence that needed re-reading for clarification of statement, question or thought. ;)

    Regarding my skepticism; it's no less at this moment in time than anytime during this thread. I still can't get my head around my starter motor analogy. They draw an enormous current yet I've never seen or know of any BEMF components employed in the motor or solenoid/relay circuit. Then there's the absence of negative reviews of Bank Stare's compressor / motor. One would think that the net being being what it is would surely kickback other consumers that are frying relays.

    So yes, this thread, as stimulating as it is begs more questions than it answers. Personally, I'd love to see the motor current scoped. It would reveal much more than we can surmise with educated guesses via a global forum environment.

    Chris
     
  15. Blank Stare

    Blank Stare

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    Oct 10, 2012
    I managed to get everything back together this afternoon.

    I have another problem, I guess, probably a bad connection, possibly another bad relay.

    Symptom is simple - runs a few seconds and then just stops. I remove power from pump, wait 20 seconds or so, and it runs again. Same symptom if I take the monster diode out of the circuit.

    Due to a lack of light, and an abundance of frustration, I closed the hood, and went back to studying the schematics. I keep hoping I will figure out what I connected wrong...That's the only thing I can think of.

    I am going to trace every wire, and every connection, schematics in hand, and see if I can get it doing what it should.

    Anyways tomorrow is another day - If it doesn't snow or rain....

    Open your right hand, fingers touching other, thumb away from your fingers, and turn the palm towards your face.

    Now look at a map of North America... :D

    Persistence? And here I just thought I was stubborn. Say, could you talk with my wife? - I think she could benefit from your perspective...

    Seriously, I am also very impressed and appreciative for the "culture" of this thread. I'm sure I haven't learned half of what's been discussed here, but the willingness of people to "dumb it down" to my level of understanding has been awesome!!
     
  16. Merlin3189

    Merlin3189

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    Aug 4, 2011
    That's what I did. How did I miss Michigan ...? That's exactly what it looks like!
    And lo & behold, Wikipedia confirms mitten as a nickname for Michigan.
    Thanks.
    Yet again my knowledge increased and my interest stimulated.

    Since you have ongoing problems, I'll keep watching and see if I can think of anything helpful, but, for now, I'd better get back to work!
    Don
     
  17. Blank Stare

    Blank Stare

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    Oct 10, 2012
    Hope you had fun with my little riddle.

    Truck is frustrating me to my limits.

    I have decided to wait for spring, and nicer weather...

    ...Unless I find a garage to work in.

    So, expect to hear from me then, or anytime someone makes a post here.

    As always, Thanks.
     
  18. Blank Stare

    Blank Stare

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    Oct 10, 2012
    Nice Spring weather today.

    I took the time to trace (almost) every wire, and label them, so I don't screw up later.

    I previously installed a relay jack - so that I do not screw up relay connections (again...)

    I previously installed the 1n1190ar 40amp 600v "Diode From Hell" at the pump.

    I installed the 1n4001 / 1n5378 "combo".

    I replaced both 1n4001 diodes before the pump.

    Wiring power directly to the pump makes the pump run at full speed, and does not blow a fuse. Leaving the diode from hell out of the circuit does not seem to have any effect in this case.

    Indicator LEDs show power when SPST switch is closed, however, the pump does not come on automagically, when the pressure is at zero.

    The manual override momentary switch works, but the pump sounds slow, and the 5 amp fuse blows in about 30 seconds. There is also the smell of something hot coming from the dash components.

    I'm just not sure what I'm looking for.

    My guesses?

    ~ I did not have time to test the APS today, but that is top of my list for next session.

    ~ Relay coil may be bad. (I'll try a different one, next session.)

    ~ Pretty sure that all connections on the 5amp circuitry are making good contact, will also check this next session.

    ~ I may have an LED on the wrong side of the diode / zener combo, but I ran out of daylight this evening

    ~ When I get several hours of time during good weather, I am going to remove the dash trim, where all of the interior components are mounted. (So are all of the copper pressure lines, regulator, and gauges.) Should I look for something burned there?

    I am very certain that I have everything (re)wired correctly - I spent a lot of time chasing wires, and labeling them, to make sure.

    Suggestions are ALWAYS welcome. ;)

    Either way, I'll check in as I get time to fiddle-fart around with this little bugger.

    ~ Blank Stare
     
    Last edited: Mar 11, 2013
  19. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    652
    May 8, 2012
    If I were you I'd be checking all conductors and connections from the battery to the 30A fuse. Then from the fuse to the relay contacts and from the relay contacts to the motor. What gauge wire did you say it is?

    Chris
     
  20. Blank Stare

    Blank Stare

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    Oct 10, 2012
    The connection between both fuses and the fuse block are "home runs". That is to say, no connections between one end and the other.

    I re-attached all of the wires in and out of the relay, when I wired a relay jack into the system.
    The problem existed before that point, and has not changed.
    I will check them again, just the same, along with all other connections under the hood - Can't hurt, right?

    Battery to 30 amp fuse to relay, to Pump, and out to ground - I can't tell for sure - either 12awg or 14awg stranded.

    I'm leaning towards 12awg.

    I think I am going to bypass the coil switches in the cab, and see if I can run the pump to full pressure. Power will still run through the relay, but I'll switch the coil manually, from under the hood. It seems to me that if that works, I can pretty much rule out the 30 amp side of the system, right?

    Looks like friendly weather the next few days.

    Watch for an update.
     
    Last edited: Mar 13, 2013
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