Fronius TransSteel 2700c, Operating Instructions Manual

Page: 50 / 120

In single-phase operation a safety cut-out function prevents a triggering of the fuse at
higher welding power values. The safety cut-out function is active at fuse values of 15 A,
16 A and 20 A and determines the possible welding time, without triggering of the fuse. If
a cut-out of the welding current results due to exceeding the pre-calculated welding time,
the service code „toF“ is displayed. In addition to the readout „toF“ from now on a count-
down runs for displaying the remaining waiting time, until the welding readiness is
restored. Then the message disappears an the power source is operational again.
At a fuse value of 30 A the temperature monitoring of the power source ensures the
timely shutdown of the welding current, yet before the fuse triggers. This results in the
display of the service codes „to1“ to „to7“. Detailed information concerning the service-
codes „to1“ to „to7“ is located in chapter „Troubleshooting and maintenance, section
„Displayed service codes“. If there is no defect or soiling of the cooling components, here
the power source is also ready for welding again after an adequate welding break.
Explanation of
the term „duty
cycle“ in single-
phase operation For single-phase operation duty cycle values are given in the chapter „Technical data“,
depending on the existing fuse value and the welding current. The percentage rates of
this duty cycle values indeed relate as well to the 10-minute cycle, as explained in
chapter „Technical data“ for the general duty cycle, however the cooling phase of the
fuse is rated at only approximately 60 s. Thereafter, the power source is already opera-
tional again.
For reasons of technical standards the duty cycle in single-phase operation is only given
for the time until the cut-out within the first welding cycle takes place. If the reference to
the 10 minute cycle would also persist with regard to the cooling phase, which is usually
valid for specifying the duty cycle, in practice longer welding phases than specified would
be possible. You see that the specification relates to cooling phases of only approxim-
ately 60 s, after which the power source is already operational again.
The example given in the following shows the standard compliant welding and break
cycles, at a welding current of 180 A and a duty cycle of 15 %.
t (min:s) 1:30 2:30 6:30 7:30 9 10 4 5
I (A)
180 A
Welding time in
single-phase
operation The following diagram shows the welding time, which is possible according to the tech-
nical standards, depending on the given fuse value and the welding current.
50