Repair Manual

Published on May 2016 | Categories: Topics | Downloads: 42 | Comments: 0 | Views: 481
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repair welding inverter



I. Background and Classification for etal Modularization Sanyu Electric provides series of excellent capability production for national defense arming on the premise of high technology and great quality. Sanyu series professional inverter welding machines which applying to military and pro clients for a long time, adopt modular design and building-block combination with the characteristics of small size, light weight, high efficiency, energy saving, high duty cycle, great welding performance and wide current adjustment range. Twelve independent modules(Input Rectifier Bridge, IGBT Inverter components, CBB filtering capacitor, Intelligent Control Module, Control Transformer, Encoder,LED Screen, Reactor, High-frequency transformer, Rectifier & Current Part, Fan, Switch) are building-block combination. So any tested fault can be solved by changing fault parts. Quickness and utility! Classification and Composing of maintenance parts: 1、 Input Rectifier Bridge parts Including: Three-Phases Rectifier Bridge, Rectifier Bridge Module Board 2、 Inverter parts Including: Radiator, Inverter Switch Canals, Absorption Capacitance and Absorption Diode 3、 Intelligent Control boards: Including: Control Square Board, Main Control Board, Current Transformer 4、 Encoder parts Including: Knob, Encoder, Encoder lines 5、 Input capacitor parts Including: CBB capacitor parts 6、Others are separate maintenance parts II. Expeditious Examine Directory Rules for confirming fault point: watching, smelling, asking, checking a. Watching At first, examine the display on LED. There are three situations: i. Displaying codes of EE XX. (Solution: Judge the fault according to “The wrong type of code table”); ii. No display; iii. Display normal current value, however, machine has no output current. Secondly, open the shield and examine each component without evidence of crack or scorch along input cable. Input Rectifier Bridge, Electrolytic capacitor parts, IGBT Inverter components and output Rectifier & Current Parts are key parts. b. Smelling Find out fault point quickly due to special odor from burned electric components. c. Asking Ask user the using situation and fault evidence in detail and then judge the fault cause relying on maintenance experience approximately. Usually, it makes easier for latter repairing. d. Checking Check the working state of key components by multimeter. Due to building-block modules combination on etal welding machine, we can expeditiously find out default parts by multimeter and replace them. Maintenance for common faults:

1、 The analysis for common problems (1) LED Screen displays over-heating protection code as EE08/EE04. Welder does not work. Possible reasons: a. Continuous working time is so long that duty cycle is more than 40%-50% of welder capacity. b. The operation of cooling fan is abnormal. c. The aeration and air channels are dusty. d. Faults happen on the Intelligent Control Boards. (2) LED Screen displays open phase protection code as EE16. Welder does not work. Possible reasons: a. The three phases of input voltage are abnormal. b. The connection of input cable is abnormal. c. The connect line between AC side of Input Rectifier Bridge is loose or open phase interface of intelligent Control board is abnormal. d. 2 resistances of 75K/1W on the signal connect line of lacking-off phase are abnormal. (3) LED Screen displays under-voltage/over-voltage protection code as EE01/EE02. Welder does not work. Possible reasons: a. The input voltage is not in the range of 290V to 480V. b. Faults happen on the Intelligent Control Boards. (4) Switch is unable to open or frequent tripping operation occurs during working. Possible reasons: a. Input Rectifier Bridge is damage. b. IGBT Inverter component is damaged. c. Input CBB filtering capacitor is short circuit or crack. d. Cooling Fan is abnormal. e. Switch is short circuit. (5) Displaying is normal but welder is no output. Possible reasons: a. The sub-electrode of output High-frequency transformer is short circuit. b. Output diode of Rectifier and Current is close circuit. c. Intelligent Control Board is abnormal. (6) Welding current is unable to adjust. Possible reasons: a. Encoder does not work. b. Encoder Connection is loose or broken c. The Connection between Encoder and Intelligent Control Module is loose. (7) Current is too low to weld. Possible reasons: a. Voltage waste is increasing due to connect loosing of output power line. b. Section area of output copper cable is less than 35 mm2 or adopting aluminum cable. c. Augment the welding current. (8) Arc starting is difficult. Possible reasons:

a. Output line is loose. b. Output line is too long or aluminum cable. c. The surface of welding work piece is unclean. d. Welding rod is affected with damp. e. Grid voltage is under 310V. (9) Arc interrupts during working. Possible reasons: a. Output line is loose. b. input voltage is under 310V. c. Welding rod is affected with damp. d. Working current is over rate current for a long time. e. Output line is too long or aluminum cable. (10) Molding is bad. Possible reasons: a. Voltage fluctuates greatly. b. Use electric machine (generator). c. Welding rod is affected with damp. d. Welding current is too strong. e. Anode would meet with work piece and Cathode with welding torch when adopt basic welding rod. (11) Splash is too large. Possible reasons: a. Turn down the current. b. Drive down the arc height. c. The surface of welding work piece is unclean. (12) Arc deflection Possible reasons: a. Adjust the direction of ground wire. b. Pay attention to the wind direction during working in the open air. 2. Repairing approaches: (1) Open the case first. And then examine by naked eye that whether there are obvious fault on parts of apparatus or burned-paste or short circuit. (2) Examine whether the sub-electrode of output High-frequency transformer is short circuit. And clean the inside dust. (3) Examine all connections between lines or inserts and Control Board. (4) Examine Input Rectifier Bridge by digital multimeter. (5) Examine IGBT Inverter components by digital multimeter. (6) Examine diode of Rectifier and Current by digital multimeter. (7) Examine the input voltage and phases. Eliminate upwards faults point and change damaged parts of apparatus. Then, carefully examine all connection lines and inserts again. Checking no-load output and whether the welding state are fine after meeting with three phase 380V power.

3. Examining methods for components: Notices and points: A、 Examine the Rectifier Bridge and IGBT Inverter Component in advance when the switch fails to close. If both of them have been broken down, they must both be changed. B、 Examine the Intelligent Control Board if phenomena happens as follow: a. The output current is unstable. b. Current can be adjusted but it is no-output c. The input voltage is fine but the machine frequently displays the codes of under/over voltage EE01/EE02. The Intelligent Control Board must be examined under state power, usually including IGBT driving part test and Main control part test. Pay attention to avoid wires tapping and short. C、 Test with power is dangerous. So operator personnel should be qualified of repairing inverter welder and familiar with structure of etal welder. They also can accurately distinguish strong power and weak power in etal components. Notice: Test must be operated after full protection! Ordinary testing items and reference values see below table: Picture 1: Sketch Map of Rectifier Bridge


Picture 2: Sketch Map of Intelligent Control Board 1

11 2 10

Main Control Board
3 … 5、4 脚 6 7

Square Board


4 5


Note instruction: 1. Input Power-Supply socket 2.Thermistor Resistance lines socket 3. Encoder lines socket 4. voltage sampling line socket 5. Lack-Phase input lines socket 6. Current sampling input lines socket

7&8、IGBT driving lines socket 9. Pulse Transformer 10、 Heat Sink (The one with a flat weld-patch is Zero Potential) 11、 LED lines socket


Test Items
Output No-load Voltage

Test Multimeter Apparatus Stalls
Multimeter DC 200V

Reference Value

Test Methods
Test the voltage of output connectors with power state. Black testing-pen connect with E+ end and Red one meet with D、 A、B、C end respectively under no-power state。IF the value between E and D is about 350 or infinity, the Bridge can be considered as damage. Respectively test conductibility of 4 black diodes (16CA) on Inverter part with power break-off. If any of diodes is broken down, the IGBT Inverter part can be considered as damage. Respectively test the voltage between two groups of orange-black line and red-white line at IGBT Inverter insert on the Control Module (See Picture2) with power state. Respectively test the voltage between 4th pin, 5th pin on the main Control Module and Zero Potential with power state. (Herein, we call the flat weld-patch on Heat Sink as Zero Potential and the pin which is nearest to Pulse Transformer as 1st pin.) The procedure need to discharge of Intelligent Control Board from shield board and test the pins on the back side. It is very dangerous. Any improper operation will lead to short or even electric shock accident!


Rectifier Bridge


Diode Stall

E&D:650 E&A:350 E&B:350 E&C:350


IGBT Inverter Part


Diode Stall


Driving Part


AC 20V



Intelligent Control Board Main Control Module Multimeter DC 20V 7.9V

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