System Description; Introduction; Technical Specifications; Description Of Power Source Art. 2150 - Cebora SPOT 3500 Service Manual

CEBORA S.p.A.

2 - SYSTEM DESCRIPTION

2.1 - Introduction.

The SPOT 3500 is a multi-function system for welding, spot-welding, warming and rectifying
auto body metal.
It is made up of an electronic power source (art. 2150), and a set of accessories to adapt to
various applications and tasks (see list in Sales Catalogue).
The power source is controlled by electronic circuits, which manage its user interface and the
operation in the various tasks.

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. 2150.

Art. 2150 is an alternating voltage power source made up of a single-phase transformer and a
scr static switch, capable of partializing the mains supply voltage to adjust the output current.
Reference to fig. 3.2.1, 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 control board (27) is powered directly through the main switch (5), and also the power
transformer (26) through the switch static (14).
The control board (27) contains both the power supply circuits and those to adjust the output
current, and generates the pulses to drive the scr static switch (14) based on the incoming signals
from the switches and potentiometers on the front panel. The latter regulates the supply voltage
to the primary circuit of the transformer (26), whose secondary circuit is directly connected to
the power source output.
On the secondary circuit of the transformer (26) is a Hall-effect current sensor, which
provides the control board (27) with the current presence signal at the power source output. It is
calibrated to provide the "current present" signal when the output current exceeds approximately
100 Aac (it does not indicate the current value, but merely whether it is greater than or less than
approximately 100 Aac).
The start signal to the power source is provided by the button on the gun trigger, connected to
the control board (27) by the connector (10).
The gun also has a thermostat, also connected to the control board (27) via the connector (10),
which blocks operation of the power source in case of gun overtemperature, or with the
connector (10) disconnected. These situations are indicated upon start-up by the red led (4) on
the front panel.
To carry out the above procedures, three operating modes are available; you may select
among them using the switches (1) and (11) on the front panel:
− automatic single stroke, recommended for spot-welding;
− automatic pulse train, recommended for mending;
− manual, recommended for warming and rectifying.
In the first instance, the power source delivers the maximum output voltage for a time,
adjustable via potentiometer (2) on the front panel, which begins by starting to circulate current,
thus after both pressing the start button and after the electrode has come into contact with the
sheet metal. Once this time has elapsed, voltage is no longer output until the start button is
pressed again.
In the second instance, the power source behaves as in the previous case, with the difference
that once the output time has elapsed, there is a pause of approximately 400 msec. (fixed time)
without output voltage, after which output voltage is once again generated for a duration equal to
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