Not sure if this is the right place to post this, it is vehicle related, but more to do with electrics, i want to try and repair a faulty solenoid the internal connections in the old one have failed, so it will involve rewinding the core, (its only about the size of a cotton reel) does it need to be a special wire or would any thin copper wire work It is to operate a small hydraulic valve on a tractor (only available as a complete unit at the cost of £360 hence the attempt to rebuild it) It has a 12v supply to it and then the other end of the internal coil seems to earth to the valve body (difficult to tell) Any help much appreciated
12v solenoid
- Thread starter andyandy2
- Start date
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look for motor re-winder in the yellow pages, they should be able to help,
As for the wire, no not just any wire will do it has to be coated, to insulate it (cant remember what its called at the moment) otherwise the current will just flow through the copper, essentially causing a short,
The coating will make the current go through the length of the wire, causing the electromagnetics that operate the solenoid.
As for the wire, no not just any wire will do it has to be coated, to insulate it (cant remember what its called at the moment) otherwise the current will just flow through the copper, essentially causing a short,
The coating will make the current go through the length of the wire, causing the electromagnetics that operate the solenoid.
the wire your looking for is Enamelled Copper Wire , get bit in maplins.
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B
breezer
there is a lot more to it than you think.
its is as stated "special wire" it aslo require the exact same size (diameter) and exact number of turns. you can't also "sit and wind it on by hand" (try it with cotton and a reel and see how hard it is)
getting it rewound will not be cheap, but usulay cheaper than a new one, but as your coil is so small it may cost a bit
how do you suppose they know how many turns? they take it apart and count them. but in your case as its a single coil, they will probly pull it off and measure the length
its is as stated "special wire" it aslo require the exact same size (diameter) and exact number of turns. you can't also "sit and wind it on by hand" (try it with cotton and a reel and see how hard it is)
getting it rewound will not be cheap, but usulay cheaper than a new one, but as your coil is so small it may cost a bit
how do you suppose they know how many turns? they take it apart and count them. but in your case as its a single coil, they will probly pull it off and measure the length
Very often electrical parts on hydraulic valves are bought in by the hydraulics company and can be bought direct from the original manufacturer.
Look closely at the solenoid for any markings and it may be possible to identify the solenoid's manufactuer.
Or a photo on here and some one may recognise it.
Look closely at the solenoid for any markings and it may be possible to identify the solenoid's manufactuer.
Or a photo on here and some one may recognise it.
Double cotton covered and double silk covered. Bare copper with two counter wound layers of thread.
Some inventor used his wifes wedding dress to provide the silk to insulate the wire for one of his coils
B
breezer
A few years back I wound my own magneto coils (30,000 turns of 48 SWG enamelled copper with cigarette paper insulation between layers) then dropped them off to a local transformer manufacturer to be vacuum impregnated, but life is just too short.....
You could have a look at things like car starter solenoids as a source of a ready wound coil, depending on the duty cycle, and the amount of 'pull' you need.
Often failures are at the connections between the windings and flexible leads energing from the coil. You may be lucky and find the failure is at the end of the winding, and you can take a couple of turns of wire off to re-fix the tail without significantly impairing the performance.
You could have a look at things like car starter solenoids as a source of a ready wound coil, depending on the duty cycle, and the amount of 'pull' you need.
Often failures are at the connections between the windings and flexible leads energing from the coil. You may be lucky and find the failure is at the end of the winding, and you can take a couple of turns of wire off to re-fix the tail without significantly impairing the performance.
We put them onto the coil winder and run it backwards, then just look at the counter when it's all been run off.
Bl**dy P*ss Taker
You need enamelled wire of the same gauge as the original. You can work out what's on there already with a micrometer and some wire tables. The exact number of turns isn't critical.
Whether the job is feasible or not depends upon how many turns you've got on there. You can estimate this from the volume of the coil once you've found the diameter of the wire. If you don't have a coil winder the best way is to anchor one end of the wire at a distance and wind yourself towards it. I've done lots of coils this way, some of them with hundreds of turns. It's a tedious job but just think of the pounds per hour!
The first layer is the easy one. The turns of the next layer will want to lie in the grooves formed by those below but here's your first problem - they can't! You must jump two grooves per turn. If you can get the two jumps on opposite sides of the coil you'll be doing well! Subsequent layers will be a bit easier because the wiggles in the layer below are natural jump points. Ends can be a problem.
Hint: have some sticky tape within reach in case you need to take a break.
Here's another useful tip: If your wire gets kinked you can make it dead straight again with some judicious stretching. If you've never tried this I suggest you practice on a short piece first. Pull carefully until the wire just begins to stretch and all the kinks will vanish as if by magic.
Whether the job is feasible or not depends upon how many turns you've got on there. You can estimate this from the volume of the coil once you've found the diameter of the wire. If you don't have a coil winder the best way is to anchor one end of the wire at a distance and wind yourself towards it. I've done lots of coils this way, some of them with hundreds of turns. It's a tedious job but just think of the pounds per hour!
The first layer is the easy one. The turns of the next layer will want to lie in the grooves formed by those below but here's your first problem - they can't! You must jump two grooves per turn. If you can get the two jumps on opposite sides of the coil you'll be doing well!
Subsequent layers will be a bit easier because the wiggles in the layer below are natural jump points. Ends can be a problem.Hint: have some sticky tape within reach in case you need to take a break.
Here's another useful tip: If your wire gets kinked you can make it dead straight again with some judicious stretching. If you've never tried this I suggest you practice on a short piece first. Pull carefully until the wire just begins to stretch and all the kinks will vanish as if by magic.
Having wound transformers I would say a single coil on a cylindrical bobbin is easy enough for anyone who hasn't attempted it before.
It might not be possible to unwind old coil depending what it is impregnated with.
Reverse engineering is the hardest part. By cutting a section uoi can work out nuber of layers and from guage of wire calculate turns per layer, or count them.
I do have a winding machine, but beforehand I used a laithe and the tool guide. You have to stop at each end and change direction of travel manually.
The problem with the laithe and fine wire you are likely to be using is maintaining tension but not snapping wire. Loads of expletives used to come from my workshop on many a long evenings failure to wind a fine coil.
Back street motor rewinders actually work by hand, we used to have one in our town, but I would think he has gone bust by now he was already folding under the pressure of cheap Chinease motors which even 4 years ago were good enough and improving all the time.
But if you can find one of these guys he'd probably take it on.
It might not be possible to unwind old coil depending what it is impregnated with.
Reverse engineering is the hardest part. By cutting a section uoi can work out nuber of layers and from guage of wire calculate turns per layer, or count them.
I do have a winding machine, but beforehand I used a laithe and the tool guide. You have to stop at each end and change direction of travel manually.
The problem with the laithe and fine wire you are likely to be using is maintaining tension but not snapping wire. Loads of expletives used to come from my workshop on many a long evenings failure to wind a fine coil.
Back street motor rewinders actually work by hand, we used to have one in our town, but I would think he has gone bust by now he was already folding under the pressure of cheap Chinease motors which even 4 years ago were good enough and improving all the time.
But if you can find one of these guys he'd probably take it on.
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