Bosch Rexroth PSI 6100 L1 Series, Operating Instructions Manual

Page: 321 / 460

1070080028 / 08 Bosch Rexroth AG PSI 6xxx | 321 /460
Information on this product
" 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.
Example
1.
Calculate the max. duty cycle ED of the inverter.
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”.
1000 ms
WLD
200 ms
WLD
200 ms
Cycle time
In this example, the following result is obtained for duty cycle ED:
ED =
200 ms
1000 ms
x 100 % = 20 %
" 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.
2.
Look for the inverter‐specific load diagram in section 5.3.3 on page
322 et seq.
3.
First draw the vertical at the previously calculated duty cycle (refer to
point 1.: duty cycle ED = 20 %).
4.
Use the respective characteristics to determine the maximum
5.
permissible primary continuous current or primary peak current.
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