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Solenoid issue..
5

Solenoid issue..

Solenoid issue..

(OP)
Why me?

I get called out to a job.
"I got a new machine,(used 1980), and it doesn't work, can you take a look at it?"

I get there and it's another press...

I start trying to understand it.  Very strange. Belgium made.

It has two giant solenoids mounted up top.  One clicks appropriately and the other is dead silent.  It also smells as I get near it. Bad. No, Very Bad.

It has a name plate that sez STROKE: 8x2.  Whereas its neighbor which is shorter sez STROKE: 8

This one has 4 wires the other has two.  So I guess it has two coils in it.

We dismount it which is a lot of fun (NOT!) as it is integral with a huge solid steel spool valve that resides below the surface of the oil tank. But we get it pulled.

We get the case apart which requires grinding as some inconsiderate engineer had the ends swaged.



Here's the result (thumbnail):


Non thumbnail:
http://files.engineering.com/getfile.aspx?folder=29b6e68e-4c6c-451d-8e43-819b11671f49&file=Sol_rebuild.JPG

It's not pretty.  One coil appears to be OK. It measures 5.5 OHMs.

The other measured 0.1 OHMs.

My autopsy shows that the machine got rained on. This solenoid trapped the water that funneled into it.  The slug rusted to the bore.  The solenoid was activated and couldn't move.  Death followed shortly thereafter.  The plastic bobbin totally slumped.  The wire lost all its enamel.  This resulted in a one turn coil with very big wire.

I had to drill hunks out of the coil to get it loose enough to pry out.

Now I need to repair this. "Hurry, hurry, chop, chop."

The magnet wire measures about 0.033" diameter with the enamel burnt off.  I guess this means it's 20AWG

My biggest issues are:

What do you suggest I use to replace the plastic bobbin or where can I get them?

Do I have to somehow count the turns of this mess or can I just wrap as much 20AWG as I can around the bobbin replacement?

Any other pointers will be eagerly snatched at.

 

Keith Cress
kcress - http://www.flaminsystems.com

RE: Solenoid issue..

Suggestion No 1 - make  bobbin from layers of Armature paper or that red insulating fiber supported by a temporary steel insert to stop it swelling while you re-wind. Once rewound impregnate the coil and bobbin with epoxy to make it solid then remove the steel insert.
No idea how you are going to fix that steel housing however.
Suggestion No 2 - take it to your motor rewinder, let them deal with it.
Have fun
Roy

RE: Solenoid issue..

Yes - that's important - have fun!

Agree in all other respects, too.

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Solenoid issue..

Hey!

Do you know the manufacturer? I can speak to Belgium if you don't want to. UPS/FED/DHL, whatever can get the thing to your place in 24 hours.  

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Solenoid issue..

The number of turns is more important on AC than on DC. Not to say that the number of turns is not important on DC. On DC the Amp Turns is mostly determined by the wire gage. However, the more turns you can cram on, the higher the resistance and the less the I2R losses.
AC is more fun. The induction and the inductive reactance are proportional to the square of the number of turns. Now more turns means less Amp Turns.
BUT, I would not count the turns, but find some way to estimate them.
On the other hand, I would step back and see if another method may be found to operate the valve, which is the primary task.  
I always try to remember to step back and look at the whole picture. Often there is nothing to be gained, but sometimes plan B saves a lot of time and money.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Solenoid issue..


Save all of the coil wire, get it together and weigh it. You know the wire size, therefore the weight will give the correct turns ( or very close) if you use the correct size form and correct wire size you have it. Weigh the new wire and put the same weight of the same size wire on the repaired form. Tom

RE: Solenoid issue..

-less the weight of any epoxy or varnish on the removed wires.

RE: Solenoid issue..


Take the bobbin to a machine shop and have them turn a new one from something like nylon stock or other suitable material. Tom

RE: Solenoid issue..

I like LaffeyDD724's weight suggestion, Keith. I have had good luck measuring wire by weight on a good scale.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Solenoid issue..

With all that scrap copper, you might just about afford a beer.

RE: Solenoid issue..

3
(OP)
Great suggestions.

We have a pretty good motor shop here. Problem is they are a motor shop not a solenoid shop!  They don't have any bobbins.  Once the bobbin is squared away it then just becomes a coil winding exercise.

I haven't thrown the wire away.  But I would need to sweep up piles of drillings.  I was VERY careful to leave one side of the coil relatively undamaged so I could saw it in half and count the ends in one face. (oh boy!)

Roy; Thanks for the coil form idea. Now I need to find the armature paper. ??

The alternative is to machine it out of Nylon. (Thank you Laffey)

Keith Cress
kcress - http://www.flaminsystems.com

RE: Solenoid issue..

Keith,

Your motor shop will have the armature paper, most EASA shops stock 3-4 thicknesses.

BK

RE: Solenoid issue..



If you get a bobbin made from nylon or other suitable material it would be rigid enough to chuck in a lathe and you could wind the solenoid yourself.  Tom

RE: Solenoid issue..

Keith, Please let us know how the repairs went with the solenoid.  Tom

RE: Solenoid issue..

(OP)
Update:
Motor shop nixed the armature paper as a major PITA with high failure likelihood.  This, while standing in-between bins of armature paper.

I think it could be done but the ends to hub connection do actually pose a real pain.

I decided to go with a form.
The form needs to be;
OD: 3.925"
ID: 2.220"
Long:2.65"

A 26" piece of Nylon 6 tube with a 4+inch OD and a 2-inch ID has been ordered. +$100

A purely dimensional calculation came up with 1,017 feet of wire. A 900ft and a 500ft spool of wire have been ordered.

I'll use my flat work plate and bolt the material to it.

I'll lathe the ID up to that required and lathe down the OD.  Then I'll carve out the Wirespace.  At that point I'll wind on the new wire.

Once done I'll use a cut off tool to cut the work off the flat plate the correct length.

I'm awaiting the material.

Tomorrow I'll count the actual turns of the ruins.

Standby.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Solenoid issue..

Hi Keith

Some really great ideas here, I learn and always enjoy reading these. But need to ask.

What kind of press is this? possibly someone out here would recognize it and get you a part number. Also I was wondering why you could not consider the load and upgraded the cluster stuff solenoid.

 

RE: Solenoid issue..

(OP)
Hi flexoprinting.
It's a press-brake.  You know, a wide Guillotine looking thing.  It is used and I don't remember the make.  I could ask, or drive over and look but..

  Gunnar has offered to talk to the Belgium factory but buying Euro based custom made parts and then next day airing it,(60 pounds), from Belgium to California so I actually have it in 5 or 6 days doesn't compute,(at all).  It would be likely cheaper to replace it with OTS items. (see below)

I dialed up my hydraulics pro and ran an upgrade past him.  Besides it being a plumbing nightmare to shift to a conventional valve he estimated 40~60gpm and said it was going to be in the $800~900 realm.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Solenoid issue..

So, what is armature paper?

RE: Solenoid issue..

(OP)
Think "gasket material".  There are different varieties but it is just thick brown porous paper around 0.010-0.030" thick

Keith Cress
kcress - http://www.flaminsystems.com

RE: Solenoid issue..

Armature paper or motor stator slot paper is refered to in the industry as FISH PAPER. I think that is what is being talked about here.  Tom

RE: Solenoid issue..

I would make the spool out of thin brass tube and sheet stock and then insulate with varnished fish paper if I was in that situation.  That would give the rigidity.  Dealing with thin plastic is problematic.

RE: Solenoid issue..

Tufnol or the GRP equivalent that we call 'glassnol' at work - and no, that's not the proper name - should be easier to turn than nylon. It will definitely have better dimensional stability. Use carbide tooling though - HSS doesn't last five minutes on it.
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

RE: Solenoid issue..

Good o'l Delrin is also much easier to work.

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Solenoid issue..

(OP)
Delrin didn't appear to take the temperature I looked at.  The "Oiled Nylon" I picked is probably similar though.

Scotty the stuff I believe you are referring too is blatantly over priced.  I would guess gold plated unobtanium would be less expensive.

OperaHouse; If you'd only suggested brass sooner I would've used it.  I could've soldered the whole thing together then wrapped it.  Dang.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Solenoid issue..


Keith, you are proceeding in the right direction.

Tom

None of us are as smart as all of us.

RE: Solenoid issue..


I think that with all of the magnetic stress and shifting forces on the coil in the solenoid application that your effort will last longer with the non conductive spool. Grounding should not present a problem in the long run with the non conductive spool, the only concern would be turn to turn shorts and if wound properly that should not be a concern. Check the new magnet wire and be sure that the insulating coating is consistant, no bare spots. It may be a good idea to dip the completed coil in and insulating liquid that will dry rapidly this will tend to lock the turns so that they don't flex under the magnetic stress and help to insure that the magnet wire insulation does not fail turn to turn.
Tom

Tom

None of us is as smart as all of us.

RE: Solenoid issue..

Loctite 290 (thin, green) will wick into a solenoid coil nicely.  A spritz of the appropriate Loctite catalyst will then set it up hard.  Call your local Loctite rep; they love problems like this.





 

Mike Halloran
Pembroke Pines, FL, USA

RE: Solenoid issue..

(OP)
Thanks guys.

I await the boring bar kit and holder for my mini lathe.  Having to cut the inside 2-3/4" deep presented an issue for my lathe.  I only have 1/4" cutting tools and they sure aren't up to reaching 3 inches down a bore.

My tool holder is a 5/16" (odd size) and long boring tools rapidly get larger in diameter to be stiff enough.  Turns out I could get an adapter that will hold 1/2" tools so for $25 I have a set of boring tools and the adapter on the way.   

Of course UPS doesn't get the material up here in one day,(ground), like stated..

I'll lob in some pictures as I proceed. Eudmacation like.

 

Keith Cress
kcress - http://www.flaminsystems.com

RE: Solenoid issue..

Keith

I am sure you love getting your hands dirty. But wouldn't it be cheaper to buy a replacement coil from the OEM ?

RE: Solenoid issue..

Hi edison123

I think Keith enjoys the challenge, his answer to my similar question was cost and time. We had a comparable situation and because it was a "Hot job" our company had to pay dearly for a rewind like Keith is doing. Otherwise the OEM could not get us a part for eight days.

 

RE: Solenoid issue..

(OP)
I finished the coil.  Here's some pictures that you may find interesting.

This shows the wire, a set of boring bars, a boring bar holder, and a 26" piece of Nylon 6 Oiled.  It's green!!



This is the plate I'm going to bolt the chunk of stock to.



Like so:



This is a chunk of it.  I gave myself very little to spare. It was nasty to cut.  I used a hack saw till I was bored.  Then switched to a wood band saw that would cut 1/32" before stalling.  I essentially hacked it off using the band saw like and axe.  That's what it seemed like anyway.



Oh ooh.. This is not good.  I am so screwed!  Look how little material is available to screw into.  No way!

Turned out I had some inside jaws I didn't realize in a second three inch chuck I have.  Wow total luck.  It saved the day.   Other problems were that the tool rest on these little lathes don't back up farther than the chuck radius!  Why??  They think all people want to do is turn little rods??

Anyway after disassembling the entire tool holder and compound slides I was able to reassemble them with one bolt holding everything together allowing me to back the tool holder back enough to clear the work.



Here we go!  What's it like turning this stuff?  Different. Instead of the lead breaking off constantly like steel or auminum it never breaks. Ever!  It then catches on the work and wraps around it.  I had to stop about two times a pass and cut it all away with a box cutter.



Note the pileup in the chuck.  What a pain.



Never EVER take a thin cut to clean up your Nylon!!  This was a 3 mil pass.  The lead came off and melted right back on. That's the light stuff.  I had to scratch it all off.  Every mm.



Now that I have the cylinder actually a cylinder it's time to start the figuring.  I use a cut off tool to dive into the work piece to delineate the various areas.  Notice the groves?  Those represent the ends and the cut off from the stock.  I had only about 1/8" of an inch available after all the material I had to remove from the ragged sawn end.



Here I am tediously making passes as I remove material. I had to remove 3/4", 0.030" at a pass.  Each pass took about 4 minutes.  Stopping to cut off the lead.



In desperation after hours, I tried to just plunge the cut-off tool in as it really seems to cut the material off.  Turned out to be less than effective.



Still slogging along.



And slogging.. (AM)



Finally done with the outside figure. Time for the inside.  I must remove 0.300" and the boring bar is only allowing me to remove 0.005" a pass.  ARGH!!



Since the lead now can't wrap around the work piece it decides to just shove ahead of the tool.  At the very bottom it pops off the walls to make a delightful snarl around the tool.  Oh joy!  Eventually I was able to stop this.



Here's the rusted up mess of a slug for the inside.
I tore this apart, having to dremel all the burrs and mangling off that the guys caused trying to get the solenoid apart.

Then I chucked it in the lathe to turn the rust off of it. It was looking bent all to heck!  I had to just use emery cloth and a hand file.  Then when I went to assemble the unit it jammed up horrendously. Turns out the long end was badly bent; out of coax 0.070"  I ended up using a straight edge, a heavy vice, and a 2lb ball peen hammer to whack it with, to get it all true again.



Back to boring.  Final pass.  0.300 / 0.005 x 5 minutes = 300 minutes  <groan>



Yes!  Time for the cutoff!!  Note the distance from the face to the chuck jaws.  Man that was close.



Bobbins R us.



Here is 32gallons of Nylon thread I made.  Most of it passed directly thru my hands as I tried to keep the lead fed into the can rather than wrapping the work.
 


Fully loaded.  Next to the worst calculator HP ever coughed up. (like a hair ball)   To wrap it I chucked it into the lathe again and ran with it.  I could never get more than four layers nested before it would go random on me...

 Screw it: Random it shall be.  Random it became.

 I counted the turns in the ruined mess. It took about an hour.  Turns out it was either 1033 turns or 933.  I wasn't sure if I did 700 twice or not.   My intention was to wrap 1033 then measure the resistance and peel some back off if required. This whole plan crashed and burned.

 I could not slow my lathe down enough to humanly be able to count the turns.  It was just on the edge of possibility but coupled with everything else and having the wire in my hands it was too much to handle.   I decided that 82 turns per neat wrap layer was how to count them.  Then that all went to hell.(random)  So I ran my whole 900ft reel onto the bobbin.



Here's a close up.  I decided that if a change was needed I sure didn't want epoxy in the picture so I just wrapped it with tape tightly.



I then decided to compare the original and mine.  Turned out I bought 20AWG and the original was 18AWG!!  Ah man!  After mike-ing it umpteen times too. It was never a solid number seemed between the two sizes but afterwords the burnt stuff all seemed to measure 40mil <18AWG> when before it measured 37mil 20AWG is 35mil.  Oh well. Probably over designed anyway.

I hooked a 100W bulb in series with each coil and turned them on.  Mine was a little dimmer. Not too bad.  Less wraps but smaller wire.  Then I stuck the slug into the cores. The light dropped to about 60%; mine 50%.

Current <no slug> 0.6A;  mine 0.4A hmmm.

Lets proceed.
I assemble the unit - lots of hassles there. Bent shaft etc.

I hold the whole 40 pound solenoid together with a clamp.

Hit a coil with with 120VAC straight.  The shaft creeps out anemically.  What!! This is totally, massively underwhelming! I can overcome the shaft with my fingers.  With either coil.

I call the client and tell him.. "This looks bogus."  Can you look at the machine?  Maybe they feed these 240V?

"The transformer feeding them sez 24V."

That would be even less pull than now.  Unless it's DC!

I drag the unit over to my 1kW DC lab supply and set it to 12V.   POW!  Scary. I can't even begin to budge the shaft.  I'm afraid the clamp couldn't even hold the thing together at 24V.

I TIG weld the ends on.  So nice.  You can TIG weld things so fast you don't have to worry about the innards being torched.

I took it over today(Mon) and assembled the spool valve to it, and reinstalled it into the machine.  We got the machine running to the client's massive satisfaction.  He told me he just got a quote from the factory for a replacement for just the solenoid (62kilogram force) from Belgium.

$7,000.00

He's a happy camper.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Solenoid issue..

I told you - good old Delrin is easier.

Great job, though. And a very entertaining read, too!!

Smoked, the guy that makes it happen - or smoke!

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Solenoid issue..


Bravo, superb and magnificent, great job. Looks like a factory made item and performs like one also.
Keith, I salute you, you are true to the electrical arts and definitely have the go getter sprit. You have sucessfully climbed this mountain and now await another daunting challenge. A+
Tom

None of us is as smart as all of us.

RE: Solenoid issue..

Nice job Keith.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Solenoid issue..

Great story and pictures Kieth, your medals in the mail.
Roy

RE: Solenoid issue..

So when are you going into mass production on these?

Curt

RE: Solenoid issue..

Hi Keith

Thanks for the great read, You know with the addition of the lathe to your tool box your getting more like Norm Abram every day!, although I've never seen an oscilloscope in the New Yankee workshop.

 

RE: Solenoid issue..

(OP)
LOL,
Thanks guys.

Curt.  When the marketing is in place.  I'll sell them for only $6k!  I'll make a killing.  Hopefully the market is greater than I perceive by the large metal tab spot welded to the side of the machine with the number "009" stamped on it.   

Keith Cress
kcress - http://www.flaminsystems.com

RE: Solenoid issue..

Great story Keith. I hope you made a spare!
not sure about operating a lathe and a camera at the same time..

RE: Solenoid issue..

The trick to machining plastic is that the tool edge has to be sharp enough to draw blood with just a touch.  Tools that have touched metal are too dull.

Next time you'll know...

 

Mike Halloran
Pembroke Pines, FL, USA

RE: Solenoid issue..

(OP)
Hey after that many hours I would engage the autofeed and work on other aspects, then day dream about being finished, then remember with a heart pounding jar that true disaster was going to occur if I failed to return before the tool hit the machine somewhere.  Anyway that's how I took the pictures -(look Ma no hands!)

Mike thanks for that tip!  The boring bars were purchased new for this task. The facing tool was a carbide insert.  (Used)

Keith Cress
kcress - http://www.flaminsystems.com

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