I am building a circuit that uses coils. We can use various designs but the ready made ones are not close enough to the physical shape we need. There must be a method for custom building a coil. Does anyone know of a source and/or ideas for this?
A few questions that might help those that follow.
What metal gauge? (Relay coils (0.125mm) audio amplifier (0.8mm) or power system current transformer.)
How many? (One for a super special amplifier or millions for the new SUV ejector seat.)
What tolerance? (Coils per inch, inside/outside diameter, material resistance, required insulation between conductors and so on.)
What (specifically) is unique about your shape that "off the shelf" coils cannot fit? Do you have a "core" or former that will determine the shape?
Coils can be hand made with care and attention to detail if you only need a few. If you are after mass quantities, then look to wire or spring manufacturers. Even ask your wire supplier who else processes the size range of wire that you are needing.
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Just an Engineer from the land down under.
The unique shape has to do with fitting in a rather flat physical space. As far as the other queries- I will have to experiment with how many, gauge and so on. But the main thing is to be able to make 10 to 20 and do some tweaking on the business end.
For that small quantity, may I suggest you make a hardwood or MDF piece that is the shape of your interior volume for the coil and carefully wrap the wire around that, making sure that you keep enough spare wire at each end for connections.
You can then extract the hardwood former and make another one. That way they will be reasonably repeatable in performance. Make a few spares so that if you ever get someone else to manufacture, you can give them a physical sample to copy.
Assuming that you are using coated high purity copper wire you will have no difficulty hand forming the coils for wires even larger than 1mm diameter.
Alternatively, if one of the currently available cylindrical coils matches your needs, then you may be able to "flatten" it before instalation. Saves a lot of hunting around for different insulated wire gauges.
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Just an Engineer from the land down under.
coil winding
Re: coil winding
