System Description; Introduction; Technical Specifications; Description Of Power Source Art. 271 - Cebora Power Tig 1540 DC-HF Service Manual

CEBORA S.p.A.

2 - SYSTEM DESCRIPTION

2.1 - Introduction.

The POWER TIG 1540 DC-HF is a system for MMA and TIG welding, with arc starting in
both contact and high frequency mode.
It is made up of an electronic power source (art. 271), and a set of accessories to adapt to
various applications (see list in Sales Catalogue).
The power source is controlled by a microprocessor circuit, which manages the operative
functions of the welding system and operator interface.

2.2 - Technical specifications.

To verify the technical specifications, see the machine plate, Instruction Manual, and Sales
Catalogue.

2.3 - Description of power source art. 271.

Art. 271 is a voltage power source with controlled current, consisting of a single-phase
rectifier bridge and a DC/DC mosfet converter.
Referring to the electrical diagram in par. 5.1, drawing 4.1 and table 4.2, we can identify the
main blocks that make up the power source.
The main switch (6) powers the power board (29), which constitutes practically alone, the
complete power source. It contains both the power circuit and the control circuits to manage the
functions of the power source art. 271.
The welding current is regulated by the microprocessor of the power board (29), based on the
signals received from the connector (I), on the panel board (26), and the parameters set via the
panel board (26). The microprocessor manages the gas solenoid valve (11) in applications that
require it, and controls the condition of the supply voltage, to activate any safety devices
necessary to protect the power source (see Error codes par. 3.4).
The panel board (26) contains the leds for signaling, the buttons and potentiometer for setting
and programming the operating parameters.
The panel board (26) is fully controlled by the microprocessor of the power board (29), from
which it also receives power. Includes the connector (I) to connect the external control devices to
the power source, such as the TIG torch start button, the potentiometer for external adjustment of
the welding current, and the UP/DOWN buttons for digital current adjustment. These signals are
appropriately filtered by the components present on the panel board (26), against conducted
interference from the welding field.
Included in the power board (29) is the HF generator circuit, that together with the HF
transformer (27), allows to start the welding arc without contact between the electrode and the
workpiece. It is managed directly by microprocessor through relè RL3, based on panel board
(26) parameter set-up. In TIG operation with HF, the start signal commands closing of relè RL3,
and the power transformer secondary voltage is applied to the HF generator composed by the
following devices: RS1, RS2, RS3, CS1, CS2, L3, TF4, SC1, CS3, CS4, CS5, CS6 and CS7.
Near the output terminals (POS) and (NEG) of the power board (29), are three capacitors
(C50, C51 and C67) which serves to prevent the high voltage and high frequency pulses
generated by the HF transformer (27) travel along the circuits into the power board (29), where
they would cause malfunctions or errors. In addition, they play a decisive role in the efficiency
of starting the pilot arc with the high frequency.
The signals processed by the electronic boards and present at their connectors are listed in the
tables in chapter five of this manual.
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