Bosch Rexroth PSI 6 Serie Betriebsanleitung Seite 321

1070080028 / 08 | PSI 6xxx
Example
In addition, check the maximum permitted welding current for a wel­
"
ding time for a computational useful life of 10 million spots.
There are diagrams showing the limit at 10% duty cycle and are
considered to be a typical transformer/secondary resistance combi­
nation.
You will find the relevant load diagram of your inverter in Section
5.3.3 on page 322 et seq.
Calculate the max. duty cycle ED of the inverter.
1.
As a result of the low heat capacity of semi‐conductors, their maxi­
mum permissible duty cycle is determined on the basis of the time
ratio "weld time to cycle time".
200 ms
In this example, the following result is obtained for duty cycle ED:
ED =
" If different weld times or cycle times occur within the application,
use
• the longest welding time and
• the shortest cycle time to calculate the duty cycle.
Look for the inverter‐specific load diagram in section 5.3.3 on page
2.
322 et seq.
First draw the vertical at the previously calculated duty cycle (refer to
3.
point 1.: duty cycle ED = 20 %).
Use the respective characteristics to determine the maximum
4.
permissible primary continuous current or primary peak current.
5.
Bosch Rexroth AG
Information on this product
Cycle time
1000 ms
WLD
200 ms
200 ms
x 100 % = 20 %
1000 ms
321 / 460
WLD