Farmweld

WELDER SET-UP

Straight polarity connection

Straight polarity connection occurs when the clamp cable (with the electrode holder clamp) is connected to the negative pole (-) of the power source and the earth cable (with the earth clamp) to the positive pole (+) of the power source. The electric arc concentrates the heat produced on the piece and causes it’s melting. In this way, as the core of the electrode melts, it is deposited and penetrates into the welding joint.

Batteries

Reverse polarity connection

Reverse polarity connection occurs when the clamp cable (with the electrode holder clamp) is connected to the positive pole (+) of the power source and the earth cable (with the earth clamp) to the negative pole (-) of the power source. The heat of the electric arc is mostly concentrated at the tip of the electrode. Each type of electrode requires a specific current type (AC or DC) and, in the case of DC current, a specific polarity: the choice of the electrode therefore depends on the type of power source used. Incorrect use will cause arc stability problems and hence also welding quality problems.

The welding power source may contain special devices.
These devices are often described as follows: arc force, hot start and anti-stick
The arc force device eases the transfer of drops of melted material from the electrode to the base material, preventing the arc from extinguishing when the drops cause contact (i.e. a short circuit) between the electrode and the weld pool.
The hot start device facilitates the striking of the electric arc, by supplying an over current every time welding restarts.
The anti-stick device automatically switches off the power source if the electrode sticks to the base material, thus allowing it to be removed manually without ruining the electrode holder clamp.

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