Kemppi Kempact 253R Service Manual

Also see for KEMPACT 181A: Operating manual Quick guide

Kemppi Kempact 253R Service Manual Manual pdf 15 page image

SERVICE MANUALKEMPACT RA_V_1.214 (40)Kemppi Oy• Wire feed mechanism doesn’t have tachometer, instead motor current is driven to zero every ca. 10ms and the EMFof the motor is measured before motor current is increased again. This EMF information is then used to regulatemotor speed• The microcontroller measures motor EMF and controls motor current to regulate motor speed3.1.8.4. PWM• PWM (pulse width modulation) circuit is for controlling the inverter• Peak current-mode control is used to directly control primary current which is measured by current transformer T1 l3.1.9. Fans M001, M002• Machine fans are controlled by the control card A001 microcontroller. If there are two fans (3~models) in the ma-chine they are started in sequence so that second fan is started after 3s delay. When welding starts fans are startedand when welding stops fans are stopped after post run time• In error situation fans are always on• Fans are stopped if arc is not established during first 5s after start3.1.10. Solenoid valve Y001• Solenoid valve is controlled by control card A001 auxiliary voltage + 24 V3.1.11. Wire feed motor M003• Wire feed motor control is based on EMF (electro magnetic force) measurement principle. Wire feed mechanismdoesn’t have tachometer, instead motor current is driven to zero every ca. 10ms and the EMF of the motor is meas-ured before motor current is increased again. This EMF information is then used to regulate motor speed. Wire feedmotor speed control is done using the microcontroller. The microcontroller measures motor EMF and controls motorcurrent to regulate motor speed• There is no special wire inch button. Wire inch is started like normal welding using the gun. When the user pushesstart button wire feed motor and the power source start. Wire feed speed is creep start speed which is slower thannormal wire feed speed. If arc is not established during first 5s the power source is shut down but wire feeding con-tinues with creep start speed for 30s. When the inverter is ON operating voltage for the wire feed motor is takenfrom the output of the power source. When the inverter is SHUT DOWN after 5s operating voltage for the wire feedmotor is taken from the auxliary transformer for safety reasons. Because of this current limit of the wire feed motorhas to be lowered. For this reason also torque of the wire feed motor is reduced after 5s3.1.12. Brights led card P002• Controlled by control card A001 auxiliary voltage + 24 V3.1.13. Panel card P001• There is two panel versions R and A (R-version has limited functions). Panel is connected to the control card A001with 16-wire ribbon cableo When machine start up panel is showing power source size and SW version3.1.14. Main transformer T001• In the 181 and 251 machines the main transformer has 19 turn primary winding and center tapped secondary 2 + 2turns (turns ratio 9.5:1)• In the 253 machine the main transformer has 27 turn primary winding and center tapped secondary 2 + 2 turns(turns ratio 13.5:1)• In the 323 machine the main transformer has 25 turn primary winding and center tapped secondary 2 + 2 turns(turns ratio 12.5:1)3.1.15. Secondary rectifier card Z002• Z002 is used to rectify the secondary current. There are 4 60A diodes connected in parallel in both legs of the rectifier(V1 – V8) in 323 power source. 250 amps machine has 3+3 diodes• Capacitors C1 and C2 and resistors R3 and R4 form a snubber circuit. The snubber circuit reduces the voltage stress ofthe diodes caused by the reverse recovery current snap off• Varistors R1 and R2 are for TIG ignition spark protection