КЕДР 141, 161 Service manual
cod. 988584
TECNICA 141 - 161
TECNICA 140.1 - 142
inverter
TROUBLESHOOTING
TROUBLESHOOTING
TROUBLESHOOTING
TROUBLESHOOTING
AND REPAIR MANUAL
AND
AND REPAIR MANUAL
AND REPAIR MANUAL
CONTENTS PAGE
OPERATION AND WIRING DIAGRAMS................ 2
Block diagram 2
Analysis of the block diagram 3
Illustrations 5
Wiring diagrams 6
REPAIR GUIDE.......................................................10
Equipment required 10
General repair instructions 11
Troubleshooting and remedies 11
Testing the machine 14
Illustrations 16
REPAIR MANUAL
SPARE PARTS LIST...............................................17
REPAIR SHEET......................................................19
“reparation no problem !”
TECNICA 141 - 161
OPERATION AND WIRING DIAGRAMSOPERATION AND WIRING DIAGRAMS
OPERATION AND WIRING DIAGRAMSOPERATION AND WIRING DIAGRAMS
BLOCK DIAGRAM
OUTPUT
EMC FILTER II°
INDUCTANCE
DIODES
SECONDARY
POWER
TRANSFORMER
CURRENT
TRANSFORMER
CHOPPER
10
9
8
7
MAXIMUM
CURRENT ADJUST.
ALARM LED
19
17
CURRENT
POTENTIOMETER
ALARM BLOCK
ADDER
18
16
15
CONTROL
6
5
PRIMARY CURRENT
READER AND LIMITER
DRIVER
13
12
DUTY CYCLE
MAKER
14
FILTER
RECTIFIER BRIDGE
PRE-CHARGE
PRIMARY
EMC FILTER
INPUT
4
3
2
1
FLY-BACKPOWER
POWER SUPPLY
FAN
SUPPLY
LED
11
24
25
UNDERVOLTAGE
SAFEGUARD
23
OVERVOLATGE
SEFEGUARD
GALVANIC
SEPARATOR
POWER
TRANSFORMER
THERMOSTAT
22
21
20
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TECNICA 141 - 161
ANALYSIS OF THE BLOCK DIAGRAM
NOTE: Unless indicated otherwise, it should be assumed that
the componentsare assembledon thepower board.
Block 1
EMC Filter
Consisting of:C1, L1,C5, C6.
Prevents noise fromthe machinefrom beingtransmitted along
the mainpower lineand viceversa.
Block 2
Pre-charge
Consisting of:K1, R1.
Prevents the formation of high transitory currents that could
damage the main power switch, the rectifier bridge and the
electrolytic capacitors.
When the power source is switched on the relay K1 is deenergised, capacitors C2, C3, C4 are then charged by R1.
When thecapacitors arecharged therelay is energised.
Block 3
Rectifier bridge
Consisting of:D1.
Converts the mains alternating voltage into continuous pulsed
voltage.
Block 4
Filter
Consisting of:C2, C3,C4.
Converts the pulsed voltage from the rectifier bridge into
continuous voltage.
Block 5
Chopper
Consisting of:Q1, Q2.
Converts the continuous voltage from the filter into a high
frequency square wave capable of piloting the power
transformer.
Regulates the power according to the required welding
current/voltage.
Block 6
Current transformer
Consisting of:T2.
The C.T. is used to measure the current circulating in the
power transformer primary and transmit the information to
block 14(primary currentreader andlimiter).
Block 7
Power transformer
Consisting of:T3.
Adjusts the voltage and current to values required for the
welding procedure. Also forms galvanic separation of the
primary from the secondary (welding circuit from the power
supply line).
Block 8
Secondary diodes
Consisting of:D21, D22,D23 .
D21 converts the current circulating in the transformer to a
single direction,preventing saturationof thenucleus.
D22, D23 recirculate the inductance output current (block 9)
when the IGBT's are not conducting, bypassing the power
transformer (block7).
Block 9
Inductance
Consisting of:L2.
Levels the secondary board diodes’ output current making it
practically continuous.
Block 10
Secondary EMC Filter
Consisting of: C31, C32.
Prevents noise from the power source from being transmitted
through thewelding cablesand viceversa.
Block 11
Flyback power supply
Consisting of:T1, U2.
Uses switching methods to transform and stabilise the voltage
obtained from block 4 (filter) and supplies auxiliary voltage to
power block12 (driver)and thecontrol board correctly.
Block 12
Driver
Consisting of:ISO2, ISO3.
Takes the signal from block 11 (flyback power supply) and,
controlled by block 14 (duty cycle maker), makes the signal
suitable forpiloting block6 (chopper).
Block 13
Primary current reader andlimiter
Consisting of: R20, R37, R38and partof thecontrol section.
Reads the signal from block 6 (current transformer) and scales
it down so it can be processed and compared in blocks 14 and
15.
Block 14
Duty cycle maker
Consisting of:U2 (controlboard).
Processes the information from block 15 (adder) and block 13
(primary current reader and limiter) and produces a square
wave with variable duty cycle limiting the primary current to a
maximum pre-setvalue underall circumstances.
Block 15
Adder
Consisting of:U1C (controlboard).
Gathers all the information from block 13 (primary current
reader and limiter), from block 16 (alarms) and from block 18
(current potentiometer), and produces a signal with a suitable
voltage forprocessing byblock 14(duty cycle maker).
Block 16
Alarm Block
Consisting of:U1A, U1B(control board).
When an alarm is detected the power source output current is
drastically reduced by making direct adjustments to block 14
(duty cycle maker) and directly changing the reference signal
obtained fromblock 18(current potentiometer).
Block 17
Alarm LED
Consisting of:D26.
It isswitched onby block16 (alarms) inthe eventof:
1) Triggering of thermostatic capsule/thermostat on power
transformer.
2) Triggeringdueto undervoltage.
3) Triggeringdueto overvoltage.
4) Short circuit at output (electrode holder clamp and earth
cable connected to one another or electrode stuck to piece
being welded).
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TECNICA 141 - 161
Block 18
Current potentiometer
Consisting of:R7.
This is used to set the reference voltage needed to adjust the
output current: when the potentiometer knob is turned the
cursor voltage varies, thus varying the current from the
minimum tothe maximumvalue.
Block 19
Maximum current adjustment
Consisting of:R32, R33,R42.
Used to adjust the maximum cutting current to be supplied by
the powersource.
Block 20
Power transformer thermostat
Consisting of:ST1.
When the temperature of the power transformer is too high,
this safeguard is triggered. It is reset automatically after the
alarm condition hasceased.
Block 21
Galvanic separator
Consisting of:ISO1.
The signal arriving from block 20 (power transformer
thermostat) is separated galvanically and sent to block 16
(alarms) fordetection ofa possiblealarm event.
Block 22
Overvoltage safeguard
Consisting of:R3, R4and partof the controlsection.
If the main supply voltage exceeds the maximum value this
safeguard triggers (a tolerance of approx. ±15% of the power
supply voltage is allowed: outside this range the safeguard
triggers).
Block 23
Undervoltage safeguard
Consisting of:R5, R6and partof control board.
If the main supply voltage falls below the minimum allowed
value this safeguard triggers (a tolerance of approx. ±15% of
the power supply voltage is allowed: outside this range the
safeguard triggers).
Block 24
Power supply LED
Consisting of:D2.
Indicates when the power source is correctly powered and
ready foruse.
Block 25
Fan
Consisting of:V1.
Powered directly by block 11 (flyback transformer) and cools
the powercomponents.
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ILLUSTRATIONS
PRIMARY EMC
(1)
FILTRE
TECNICA 141 - 161
(11)
(3)
RECTIFIER
BRIDGE
(2)
PRE-CHARGE
FLY-BACK
POWER SUPPLY
Power board
(7)
POWER
TRANSFORMER
CONTROL
BOARD
(4)
FILTER
(18)
CURRENT
POTENTIOMETER
(24)
POWER
SUPPLY
LED
(17)
ALARM
LED
(21)
GALVANIC
SEPARATION
(10)
SECONDARY
FILTER EMC
(5)
CHOPPER
(12)
DRIVER
(6)
CURRENT
TRANSFORMER
-5-
(8)
SECONDARY
DIODES
(9)
INDUCTANCE
TECNICA 141 - 161
WIRING DIAGRAMS
General wiring diagram
-6-
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