General Basics - Functional Principle; Inverter Principle - General Remarks; Resonance Converter - Fronius Transpocket 1500 Erdstrom Serviceanleitung, Ersatzteilliste

General basics - Functional principle

Inverter principle
- General (dm³)
remarks
Fig.1
It is precisely this connection between volume and frequency that is exploited by
inverter power sources. This is the reason why inverter power sources can have low
weight and compact dimensions without sacrificing power and performance. As a result,
they are much lighter to carry, which is particularly important for use out in the field.
Also, thanks to their small volume, inverters take up less space in the often cramped
conditions found in workshops.
Phase
PEN
conductor
Fig.2
Following this, the high-frequency voltage is fed to the transformer. The output voltage
from the transformer is then rectified once again in the secondary rectifier (secondary
diode).
On inverter power sources, the welding properties do not depend on the design of the
transformer and the output inductor. This makes it possible to flexibly adapt the power
source characteristic to the job in hand.
Resonance
converter
80V
Fig.3
V
20
1
50
Volume of a transformer, as a function of its
frequency
A n s t e u e r u n g
d i g i t a l
Block diagram of an inverter power source
Pmax! With PWM, high
U
out
max. power is needed
Characteristic
(for pulse-width
modulation
Ideal
characteristic
Adjustable
Standard character- short-circuiting
istic (for electrode) dynamic
140 A
Characteristic on resonance converter, rod-
electrode
The TP 1500 power source functions by
the inverter principle. The distinguishing
feature of inverter power sources is that
the welding transformer's location in the
energy path does not come until after the
switching transistor. This enables the
transformer to be designed for a much
higher frequency, regardless of the (50
Hz) mains frequency. The reason for this
is an electrotechnical law which dictates
that the weight and volume of a
100 k
transformer will depend on the frequency
f (Hz)
at which it is operated. The higher the
frequency, the lower the volume of the
transformer.
Another advantage is their high electrical
-socket
efficiency (up to 90%). Before the high
switching frequency can be exploited, the
mains voltage must first be rectified in the
primary rectifier. The DC voltage delivered
by the primary rectifier is converted to a
high frequency with the aid of a transistor
-socket
switch. This is what gives "inverter" power
sources their name (to invert = to convert
or transform).
Based on the inverter principle, the
development effort to develop the
resonance converter for the TP 1500
power source took wholly new
approaches. Instead of a simple transistor
switch or pulse-width modulation, the
principle of a resonance converter is used
for generating the high-frequency primary
voltage.
max. 180 A
I
out
18