Kemppi MASTERTIG AC/DC 2500W, Service Manual

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TECHNICAL SERVICE MANUAL FOR MASTERTIG ACDC
APPENDIX 1.
CHANGING THE SET OF DIODES IN SECONDARY RECTIFIER
OF MASTERTIG ACDC
Rectifier diodes in Mastertig ACDC are plastic case types (2 x 15 A) These are
mounted with pressure bars ensuring good thermal transfer to the heat sink.
Individual diodes can not be changed because they are specially selected for
parallel connection using a forward voltage measurement hence only diodes
with the same characteristics can be used.
This means that if one diode is
failed the whole set of diodes must be changed!
The mounting torque for tightening screw of pressure bar is 3.0 Nm . The
amount of silicon paste used should not be excessive because electrical
contact is made through the mounting surface of components.