The contact at the connection of conductors of different metals will be reliable only under ideal conditions, the main of which is lack of moisture. However, the air that surrounds us always contains water particles in the form of steam. Therefore, when connecting two conductors with different electrochemical potentials, galvanic couple is formed.
The higher the value of the electrochemical potential arising from the contact of two conductors, the higher will be the value arising between them galvanic current, therefore, the more actively as a result of electrocorrosion will be destroyed, one of the conductors. The contact at the wire connections going to fade, accompanied by increase of resistance, which inevitably will lead to heating of wires and sparks with all unpleasant consequences.
Since the electrochemical potential generated between the conductors of aluminium and copper is one of the most high and equal to approximately 0.65 mV, the only way out of this situation — to use for their connections intermediate material. The optimal choice in this case is a steel or lead-tin solder.
Connection conductor stranding
Despite the fact that the connection wires by twisting is prohibited by the rules of SAE, this method due to its simplicity continues to be widespread. If to refuse such a connection technology for a number of reasons not possible, perform it at least correctly.
After removing from the ends of the wires insulation, copper conductor it is necessary to tin lead-tin solder. Do not try to do the same with a conductor of aluminium at home using a standard soldering iron and solder you will not succeed.
Further perform the twist so that the conductors are mutually coiled around each other. For thin wires with a diameter less than 1 mm, the number of turns in the twisting shall not be less than 5, for thicker conductors it is possible to do 3 turns.
When complete, you must perform the insulation of the strand with adhesive PVC tape or special caps
Using terminal block
The easy way to connect wires is to use terminal blocks. The method of fixation of the wires of the terminal block are divided into 2 types: with a tightening screw with clamping plates. The last type Shoe is preferable, because the wiring tightening screw does not exclude the possibility of damage to the conductor by the screw during the screwing. particularly susceptible to damage from stranded copper and aluminum conductors.
Clearing the end of the wire from the insulation at a length of about 5 mm, it is inserted into the mounting hole, then firmly tighten a screw.
Connection by spring terminals
Simplify installation and wire connection terminal blocks with spring clamp. Fixation of the conductor in them is not a screw, and by means of a spring which presses the contact plate to the wire. Terminals with spring clamp are disposable, not allowing to withdraw the conductor from the clamp after locking, and reusable, is equipped with a special locking lever.
For connection of conductors with disposable spring clips enough to insert with force into the hole of the pad the end of the stripped cables. The reusable terminal blocks with spring clamp first to pull the lever-the latch is inserted into the pin hole end of the wire, after which the lever is lowered.
For use with aluminum and copper wires it is better to use the spring terminals with the contacts of the bimetal plate coated with her paste, which prevents oxidation of the conductors.
Is realized by means of screw, nut and several washers. Reliable and inexpensive way, depending on the length of the screw, to connect different number of conductors of arbitrary thickness.
With the ends of the wires remove the insulation for length equal to 4 diameters of the connecting screw and wrapping them around the screw, forming rings. Wearing screw spring washer first, then normal, wear ring formed of one conductor. Wearing regular washer on the screw wear ring of the second conductor, then another washer, then screw the nut and tighten it firmly.
Stranded copper wire before connecting it is recommended to tin lead-tin solder.
the Permanent connection of conductors
If you have a special rivet tool to connect the copper wire with aluminum, using rivets. Formed on the ends of the wires jump rings, as in the case of a threaded connection, on the rivet, you must first put a ring of aluminum wire and then the spring washer. Then puts a ring of copper wire and plain washer. Inserting the rod into the riveting machine, squeeze the handle until it clicks showing that circumcision of the excess rod.
In the case of conductors of large cross-section to connect them use a special sleeve-connectors. Inside the shell is placed connect the wires, and then a special crimping tool sleeve is compressed in several places. The resulting connection is robust, reliable and durable.
Good luck to you! Let you will succeed!