System Description; Introduction; Technical Specifications; Description Of Power Source Art. 296 - Cebora POWER PLASMA 3100 Service Manual

CEBORA S.p.A.

2 - SYSTEM DESCRIPTION

2.1 - Introduction.

The POWER PLASMA 3100 is a plasma arc system for cutting electrically conductive
materials.
It is made up of an electronic power source (art. 296), with built-in torch and trolley for easy
movement.
The power source is controlled by microprocessor circuits, which manage the operative
functions of the cutting system and operator interface.

2.2 - Technical specifications.

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

2.3 - Description of power source art. 296.

Art. 296 is a direct current power source with controlled current, consisting of a single-phase
rectifier bridge and a DC/DC mosfet converter.
It may be powered at either 115 or 230 Vac; the unit adapts automatically based on the
voltage applied to the power source input.
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 (9) powers the filter board (36), which contains the filter to reduce
conducted interference reflected in the mains.
The power board (35) is the actual source of the cutting current, which converts the
alternating voltage at the filter board (36) output into direct current, continuously adjusted based
on cutting needs. It contains the power circuits and control circuits that adjust the cutting current.
The cutting current is adjusted in the power board (35), based on the signals generated by the
microprocessor of the panel board (31), according to the signal of the current potentiometer (M)
and the operating mode set using the button (P), located on the front panel of the power source.
The microprocessor also controls the conditions of the mains voltage, to select the supply
voltage (115 or 230 Vac), and protections needed to safeguard the power source (see Alarm
signals, par. 3.4). In the case of a 115 Vac power supply, a special voltage duplicator circuit is
activated on the power board (35), to raise the direct current on the capacitors of the power board
(35) to a value close to what would normally be had with a supply voltage of 230 Vac, thus
approximately 320 Vdc.
In this way the DC/DC converter, serial-connected downstream from the capacitors on the
power board (35), always works in the same way whatever the supply voltage.
Similarly, the fan (15) is also always powered at 230 Vac, even with a power source supply
voltage of 115 Vac.
The panel board (31) is the control panel of the power source, and receives the power from
the power board (35). It contains the leds to indicate the operating status, the button to activate
the "PILOT SELF-RESTART", and the cutting current adjustment knob. This board also
receives the temperature signals from the thermostat on the power board (35) and the plasma gas
pressure signals from the pressure switch (32). All of these functions are managed by the
microprocessor on the panel board (31).
Connected to the output of the power board (35) is the HF board (22) which, together with the
HF transformer mounted on it, generates the high voltage and high frequency pulses necessary to
strike the pilot arc. Its operation depends on the presence of AC voltage on the secondary circuit
of the power transformer on the power board (35), and is controlled by the HF enable signal
generated by the microprocessor of panel board (31).
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31/05/02