Kemppi WELDFORCE KPS 3500 User manual

Service manual
Ver. 1.0

Contents
Technical data…….……………………………....………3
Switches and connectors…....…………………………….3
Operation principle………………………………………4
Simplified main circuit diagram…….………...………...5
Main circuit components………………………………...5-8
Control cable connectors………………………………...9
Troubleshooting diagram….........……………………….10
Control card A001 layout….…………………...………..11
Control card A001 jumper….....................……………...11-12
Control card A001 leds….………….……………………12
IGBT gate pulse…...……………………………………...13
Voltage over the lower IGBT………….……………....... 14
Voltage after the secondary diode cards….………….....15
Cooling unit control…….............………………………...16
Structure (Kemppi WELDFORCETM 4500)……………...... 17
Notes……………………………………………................18
2

Supply voltage 3~50/60 Hz 400 V –15…+20 % 400 V –15…+20 % 400 V –15…+20 %
Loadability (+ 40°C)
60 % ED
80 % ED
100 % ED
350 A (15 kVA)
320 A (13,5 kVA)
450 A (21,5 kVA)
420 A (20 kVA)
380 A (18,5 kVA)
550 A (28 kVA)
500 A (24,5 kVA)
440 A (21 kVA)
Supply cable /
Fuses
4 x 6 S – 5 m
25 A slow
4 x 6 S – 5 m
35 A slow
4 x 6 S – 5 m
35 A slow
Adjustment range of welding current
and voltage
MMA
MIG
10 A…320 A
12 V… 37 V
10 A…420 A
12 V… 39 V
10 A…520 A
12 V… 42 V
Max. welding voltage 46 V / 300 A 46 V / 400 A 50 V / 500 A
OCV appr. 65 V appr. 65 V Appr. 65 V
Idling power < 75 W < 75 W < 75 W
Efficiency on nominal values Appr. 85 % appr. 85 % appr. 85 %
Power factor on nominal values appr. 0,93 appr. 0,93 appr. 0,93
Degree of protection IP 23 C IP 23 C IP 23 C
Weight 37 kg 41 kg 48 kg
Auxiliary units power supply 50 VDC (6,3 AT) 50 VDC (6,3 AT) 50 VDC (6,3 AT)
Technical data
KPS 3500 KPS 4500 KPS 5500
1I/0-signal lamp
2Overheat protection lamp
3 Main switch
4control cable connection fuse
6,3 A slow
5Supply cable
6,7 Welding current connections
8Return current connection
9Control cable connections
1
2
3
4
5
6
78
9
Switches and connectors
3

Operation principle
KEMPPI WELDFORCETM-power sources are versatile, MIG/MAG- and MMA-suitable inverters.
KEMPPI WELDFORCETM-power sources are based on IGBT technology and controlled by PWM
principle. The inverter frequency changes by the load, in range of 14 - 24 kHz.
KEMPPI WELDFORCETM-power sources are microprocessor controlled, so all welding
characteristics are programmatically generated.
KEMPPI WELDFORCETM-power source´s operation principle is shown below:
appr. + 570 V
C2
C3
V2
V3
T1
KEMPPI WELDFORCETM-power source´s
power stage is a traditional half bridge,
where the intermediate circuit DC-voltage is
halved by working capacitors C2 and C3.
IGBT-transistors work as power switches.
When both IGBTs are non-conductive, no
power is transferred.
When the upper IGBT V2 is conductive, the
main transformer T1´s primary side has
positive voltage. When the lower IGBT is
conductive, there is negative voltage.
Power is adjusted by altering the IGBT-
transistors conductive timings (PWM).
The main transformer T1´s secondary
voltages are rectified by a full-wave
rectifier.
Voltage over the lower IGBT with minimum values.
(MIG 10A/14,5V)
100V, 20µs/DIV
UV3
Voltage over the lower IGBT with maximum values
(MIG 450A/36,5V)
100V, 20µs/DIV
4

Simplified main circuit diagram
V1
V2
V1
V2
Control card A001
L1
L2
L3
The filter card Z004 dampens the electromagnetic disturbances conducting to the net (EMI).
Varistors (550 V) form an overvoltage protection against low energy voltage spikes. Note! Filter
card Z004 and varistors are mounted before the main switch S001!
Main circuit components
Filter card Z004 Varistors (550V)
Main switch S001
5

Main circuit components
Rectifier unit
3500, 4500: 60 A/ 1600 V
5500: 100 A/ 1600 V
Rectifier unit
35 A/ 600 V
Varistor
550 V
Primary choke
The primary rectifier VG101 rectifies the net voltage. The primary choke L001 limits the in-
rush current during switching and filters the DC-voltage together with the smoothing capacitors.
Smoothing capacitors
2 x 25 µF/ 700 VDC
Work capacitors
3500: 18 x 0,15 µF/ 1000 VDC
4500: 22 x 0,15 µF/ 1000 VDC
IGBT-module
3500: 100 A/ 1200 V
4500: 150 A/ 1200 V RC-protection
RC-protection
Discharge resistors
(KEMPPI WELDFORCETM 3500and 4500)
6

Main circuit components
Smoothing capacitors
4 x 25 µF/ 700 VDC
Work capacitors
30 x 0,15 µF/ 1000 VDC
Discharging resistors
4 x 33 kΩ/ 2 W
IGBT-modules
2 x 200 A/ 1200 V
RC-protection
Inverter´s main parts are the workcapacitors, IGBT-transistors and the main transformer T001.
Inverter´s power adjustment is based on pulse width modulation (PWM). RC-protections ease the
stress on the semiconductors.
(KEMPPI WELDFORCETM 5500)
The chokes LL301 and LL302 of the commutation unit reduce the losses of the IGBTs during
the switching. The current transformer LT301 monitors the primary side current. According
to it´s measurement the frequency of the power source is adjusted (14… 24 kHz).
Commutation unit
7

Main circuit components
Diode cards
Secondary choke and shunt resistor
Shunt amplifier
OCV smoothing circuit
XX
The main transformer T001 secondary voltages are full-wave rectified by the diode cards. The
secondary voltage waves are dampened by secondary choke L002. The secondary circuit current
is measured by a shunt resistor. The shunt´s voltage is amplified by shunt amplifier A001/2 and
taken to control card A001´s PWM-adjuster.
Control cable connection power supply
+ 50 VDC
Control card A001
power supply 2 x 20 VAC
No 220 V coil!
From auxiliary transformer T002 secondary voltages are formed the supply voltages for A001
and control cable connection´s auxiliary units.
8

Control cable connections
Control cable connections
The auxiliary units are connected to power source´s control cable connectors X006 and X007.
The cooling unit KWU-10 is connected to connectors X010 and X011.
KPS 4500 KPS 5500
The control card A001 is similar in all Kemppi WELDFORCETM -power sources. The machine size
is coded with short circuit loops, except in Kemppi WELDFORCETM 3500, which has no short
circuit loops.
A
B
C D
E
F
G
9

Troubleshooting
PROBLEM POSSIBLE CAUSE REMEDY
The power source will not start.
The signal lamps remain blank.
The net fuse has burnt. A faulty
supply cable.
A faulty auxiliary transformer
T002.
A faulty control card A001.
Check the net fuses. Check the 3
phases coming to power source´s
connector X1.
Check the auxiliary transformer´s
secondary voltages from control
card A001, between connectors
X12 - X11 and X12 - X10 (appr.
20 VAC).
Update the control card´s flash
memory program. If
reprogramming will not solve the
problem, replace the control card
A001.
Net fuses blow immediately
when the power source is
switched on.
A faulty primary circuit
semiconductor.
Check the semiconductors on the
primary side.
The power source doesn´t reach
maximum power.
The net fuses has blown. A faulty
supply cable. A faulty primary
rectifier VG101. A faulty secondary
diode card.
Check the net fuses, supply cable
and the primary rectifier VG101.
Check the condition of the
secondary diode cards.
The fans remain rotating after
power source startup.
A faulty control card A001. Reprogram the control card A001
flash-memory. If reprogramming
will not solve the problem, then
replace control card A001.
The machine may only be repaired by a technician or a workshop licensed and authorized to
do the job!
First do a visual check to find any possible loose connectors, broken wires or signs of
overheating.
Troubleshooting diagram
10