Use of Bondable wire allows coils to be self-supporting, so that bobbins, taping, or additional varnishing is not necessary. Bondable wire consist of standard magnet wire insulations overcoated with a thermoplastic polymer that can be temporarily softened by either heat or solvent, or both.
Three Common Methods of Bonding
1. Solvent Bonding
Some Bondcoats can be activated by the application of certain solvents during or after coil winding. The solvent may be applied to the wire via a wick during the winding operation or the finished coils may be dipped in a bath of solvent after the winding process. In either case, the unit should be heated again to drive off residual solvent and to complete the bonding of coils.
2. Heat - Oven Bonding
After the coils are formed, the unit is heated in an oven, causing the bondcoat to flow, bonding the adjacent turns of wire together.
3. Heat - Resistance Bonding
Resistance heating in similar to oven heating, except that passing current through the formed coils supplies heat. Time, voltage and current are all unique to each application.
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