Load And Rating; Basics; Is The Inverter Overloaded - Bosch Rexroth PRC 7000 Betriebsanleitung

242 / 334 Bosch Rexroth AG
Information on this product
5.3

Load and rating

5.3.1

Basics

5.3.2

Is the inverter overloaded?

Example
These conditions were taken into account in the design of our systems.
Our load diagrams are therefore extended by a peak current curve with
calculatory maximum life. The calculated life takes into account the
thermal rise which is influenced by the welding current, secondary cir­
cuit resistance, the welding time and the ambient temperature, among
others.
The load diagrams are specified for 45°C ambient temperature.
The maximum load of a medium-frequency inverter is generally speci­
fied by the assignment of types to specific maximum welding trans­
former sizes.
Nevertheless it must be ensured that the present application does not
lead to overload of the units.
Overload by inadequate project engineering
Possibility of damage to the device, reduction of useful life!
" Check the actual load of the medium-frequency inverter!
Damages due to overload will result in the extinction of any
warranty claims.
This can be checked using load diagrams. They represent the
• primary output currents (I
• duty cycle (ED in %) for an ambient temperature of 45°C (also refer to
page 242)
that can be switched by the medium-frequency inverter.
You will find the relevant load diagram of your inverter in Section
5.3.3 on page 244 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
PRC7000 |
NOTICE
in A) as a function of the
PRIM
Cycle time
1000 ms
WLD
200 ms
R911172834 / 02
WLD