MERKLE E 420 DC Operation Manual

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Operation Manual

MMA/Stick Elektrode Unit

Model E 420 DC

MERKLE Schweißanlagen-Technik GmbH Industriestraße 3 D-89359 Kötz Tel.: (08221) 915-0 Fax: (08221) 915-40 www.merkle.de

Inhalt Seite

1 Accident prevention regulations 2

1.1 Safety instructions 2

2 Duty cycle 4

3 Instructions to avoid interferences due to electromagnetic influences EMC 4

4 Technical Data 6

4.1

MMA/Stick Electrode Welding Unit Model E 420 DC 6

5 Start Up 7

5.1 Installation of the Machine 7

5.2

Main Supply 7

5.3 Connection of the welding cables 7

5.4 Earth Lead (Work Cable) 8

5.5 Operation mode: TIG 8

5.6 Operation with the unit connected to a generator 8

5.7 Cable prolongations 8

5.8 Transport 8

6 Generalities of the welding unit Model E 420 DC 8

6.1 Cooling of the power modul 9

6.2 Electronics 9

6.3 Electrode Holder 9

6.4 TEDAC-System 9

7 Current Adjusting 9

8 Operation of the unit E 420 DC 11

9 Cleaning 12

10 Maintenance and Accident Prevention 12

11 Trouble Shooting 12

12 Partlist and wiring diagram 14

12.1 Partlist E 420 DC 14

12.2 Wiring diagram E 420 DC 15

Dear customer,

we wish to thank you for choosing a MERKLE welding machine. In doing so, you have demonstrated to us the trust you place in our products.

With best wishes

MERKLE Schweißanlagen Technik GmbH

1 Accident prevention regulations

The following accident prevention regulation is applied for welding with MMA welding units, type E 420 DC: VBG 15 / BGV D1* Welding, cutting and allied processes. A copy of this regulation should be readily accessible in every welding shop. The stipulations of this regulation are to be observed in the interests of safe and correct welding operation.

Available from the trade association responsible or Carl Heymanns-Verlag, Luxemburger Strasse 449, 50939 Cologne.

1.1 Safety instructions

This unit is manufactured according to the requirements and stipulations of EN 60974.1 / VDE 0544. The accident prevention regulations “Welding, cutting and allied processes” (VBG 15 / BGV D1) of the trade association for precision engineering and electrical engineering are as well valid.

1) In case of an accident, the welding unit must be disconnected from the mains immediately.

2) If electrical contact voltages arise, switch off the unit immediately, disconnect it from the mains and proceed to inspection by a qualified electrician or by our Service Department.

3) Before opening the unit, disconnect it from the mains supply.

4) Repair work may only be carried out by a skilled electrician or by our Service Department.

5) Before the unit is put to operation, check it visually, as well as the torch and all cables and connectors regarding possible external damages.

6) Personal protective equipment in accordance with DIN EN 175, DIN EN 379 and

DIN EN 169.

During the work, the welder’s body must be completely protected against radiation and burns by means of protective clothing and face protection. Long gloves, aprons and welding shields with welding filters conforming to DIN EN 470-1 and BGR 189

must be worn. Synthetic clothing are excluded. Shoes must be closed, not opened (due to spatters). If necessary, protective headwear must be worn (e.g. for overhead welding). If cover glasses are used, these must be in accordance with the norms specified above. As additional protection for the eyes against UV radiation, safety goggles with side shields and corresponding face protection in accordance with BGR 192 and BGI 553 must be worn. Accident prevention regulation BGV D1 § 27 stipulates that it is the responsibility of the employer to provide suitable personal protective equipment, while § 28 stipulates that it is the responsibility of the insured to wear suitable clothing.

7) Protection when welding under increased electrical risks Welding rectifiers and welding power sources which can optionally be used for either direct or alternating current must be marked "S" in accordance with EN 60974-1 and BGI 534. Use insulating materials to protect you against contact with electrically conductive parts and damp floors. Wear dry, undamaged work clothing, long gloves and footwear with rubber soles. Ventilate rooms, install extraction systems if required, and wear respiratory protective equipment if necessary (see Procedural instructions BGV D1

§ 27 and BGI 533, Section 5).

8) In order to prevent stray currents and the effects thereof (e.g. destruction of electrical

protective ground conductors), the welding return cable (workpiece cable) must be connected directly to the workpiece to be welded or to the table (e.g. welding table, grid-type welding table, workbench) supporting the workpiece (see BGV D1 § 20). When installing the ground connection, assure that there is a good electrical contact (remove rust, paint, etc.).

9) During welding pauses, the welding torch is to be laid down on an insulated surface or hung up in such a way that it is not in contact with the workpiece and its support connected to the welding power source (see § 20 BGV D1). In the case of longer work pauses, the welding unit must be switched off and the gas cylinder valve must be closed.

10) The shielding gas cylinder must always be protected against tumbling downing using a safety chain.

11) Under no circumstances the unit may be put into operation while it is opened

(e.g. for repair work). Apart from the safety regulations, sufficient cooling of the electrical components provided by the fan cannot be guaranteed.

12) In accordance with BGV D1 § 5, people in the vicinity of the arc must also be informed of the hazards and protected against them. Safety partitions (“welding safety curtains”) must be erected in accordance with DIN EN 1598.

13) No welding work may be carried out on containers in which gases, fuels, mineral oils or similar substances have been stored even if they have been empty for a long time (risk of explosion). See § 31 of accident prevention regulation BGV D1.

14) Welds which will be subjected to high loads and which need to meet specific safety requirements may only be carried out by specially trained and qualified welders.

15) Never bring the torch close to your face.

16) In areas at particularly high risk of fire, the welder must obtain a welding permit and have this on his person throughout the duration of the welding work. On completion of welding, a fire-guard must be delegated to ensure fire protection.

17) Ventilation measures must be applied in accordance with BGI 553, Section 9.

18) The hazard to eyesight must be indicated by means of a sign at the work site

"CAUTION! Do not look into the arc!".

2 Duty cycle

The duty cylce measurings have been carried out in accordance with EN 60974-1 / VDE 0544 (10 min working period). 60% duty cycle means: After a 6 min. welding period a 4 min welding pause must be respected. The electrical components are thermally protected against overheating.

3 Instructions to avoid interferences due to electromagnetic influences

EMC

The welding unit has been manufactured in accordance with the requirements of guideline EN 50199 regarding electromagnetic compatibility. It is nonetheless the responsibility of the user to ensure that the welding equipment is installed and operated in accordance with the manufacturer’s instructions. If electromagnetic interference is detected, it is the responsibility of the user of the welding equipment to find a solution with the technical assistance of the manufacturer. In some cases, it may be sufficient simply to ground the welding current circuit. In other cases, it may be necessary to build a complete shield for the welding power source and workpiece using the input filters. In all cases, electromagnetic interference must be reduced to avoid any possible malfunctions.

Note:

For safety reasons, the welding current circuit may or may not be grounded. No modifications may be made to the grounding without the approval of an expert who is able to determine whether the changes might increase the risk of accidents, e.g. by allowing parallel welding current return paths which could destroy the ground conductors of other equipment. Further instructions are contained in TEC 974-XX "Arc welding equipment – installation and use".

a) Evaluation of the installation site

Before installing the welding equipment, the user must evaluate potential electromagnetic problems in the vicinity. The following must be taken into consideration:

 Other power cables, control cables, signal and telecommunication cables above, below

and next to the welding equipment

 Radio and television transmitters and receivers  Computers and other control devices  The health of people in the vicinity, e.g. use of heart pacemaker and hearing aids  Calibration and measuring equipment  Interference immunity of other devices in the vicinity. The user must ensure the

electromagnetic compatibility of other devices used in the vicinity. This may require additional safety measures.

b) Procedures to reduce emitted interference

1) Mains supply

Welding equipment is to be connected to the mains in compliance with the recommendations of the manufacturer. If interference occurs, it may be necessary to take additional precautions, e.g. filters for the mains connection. Make sure that the power cable of welding equipment is installed in a fixed position shielded by means of a metal conduit or similar. The entire length of the shield must be electrically connected. The shield must be connected to the welding power source in the way to obtain a good electrical contact between the metal conduit and the housing of the welding unit.

2) Maintenance of the welding equipment

Welding equipment must be maintained regularly in accordance with the recommendations of the manufacturer. All access and service doors and covers must be closed and fastened securely when the welding equipment is in operation. No modifications whatsoever may be made to welding equipment with the exception of modifications and adjustments specified in the manufacturer’s operating instructions.

3) Welding cables

Welding cables should be kept as short as possible and routed close together on or near the floor.

4) Equipotential bonding

It is advisable to interconnect all metallic parts in and next to the welding equipment. Metallic parts connected to the workpiece can, however, increase the risk of the welder receiving an electric shock by touching these metallic parts and the electrode simultaneously. The welder must be electrically insulated against all these connected metallic parts.

5) Grounding the workpiece

If the workpiece is not connected to the ground for electrical safety reasons, or due to the size and position of the workpiece, e.g. steel structure or outer wall of a ship, grounding the workpiece may in some cases, but not all, reduce emitted interference. It must be ensured that grounding the workpiece will not increase the risk of accidents for the user and cannot cause the destruction of other electrical equipment. If necessary, the grounding of the workpiece must be carried out by means of a direct connection to the workpiece. In countries where a direct connection is prohibited, the connection must be made by means of suitable reactors, selected in accordance with national regulations.

6) Shielding

Selective shielding of other cables and devices in the vicinity can reduce interference problems. For special applications, it may be worth considering shielding the entire welding system.

4 Technical Data

4.1 MMA/Stick Electrode Welding Unit Model E 420 DC

Primary:

Supply: 3 x 400 / 415V Frequency: 50-60 Hz Cont. power: 11,8 kVA Cont. current: 17 A Max. current: 29 A Cos phi: 0,9

Secondary:

Open circuit voltage: 80 V Welding voltage: 20-37 V Welding current: 5-420 A Duty cycle 40 % (10 min.) 420 A Duty cycle 60 % (10 min.) 350 A Duty cycle 100 % 280 A (40°C)

Protection class: IP 23 Insulation class: H Cooling: AF Main switch: 3-phase Potentiometer: welding current Potentiometer: arc force Potentiometer: hotstart time Potentiometer: hotstart current Socket: remote control Operation modes: switch: 6-step: Stick electrode, positive Stick electrode, negative Stick electrode, remote control Stick electrode, TEDAC Digital read out: welding current, with Hold function and with pre-indication Control lamp: mains ON, thermic protection, failure, Hold Power source: inverter (IGBT) Functions: hotstart, antistick, arc force, TIG liftarc stabilisation: ± 10 % mains voltage fluctuation Norm: EN 60974-1 "S" / CE Socket 70 mm²: workpiece cable Socket 70 mm²: Electrod cable with holder Power supply cable: 4 x 4 mm², 5 m long Weight: 58 kgs Dimensions l x w x h: 605 x 430 x 630 mm

Standard accessories:

Description Part No.

Earth lead 70 mm², 4 m long 022.1.0408 with plug and earth clamp Electrode welding cable 70 mm², 5 m 022.1.0449 incl. plug and electrode holder

Accessories:

Polarity change, installed inside 013.0.1075 the welding unit Hand remote control, incl. Polarity 019.0.3549 switch, cable 6 m and plug TEDAC operation, installed inside 012.0.0725 the welding unit Hand shield with TEDAC function, 012.0.0750 polarity change, 5 m cable and plug Welding cable, 70 mm², black, per m 009.0.0400

Accessories for TIG welding:

Regulator argon/CO2, single stage 012.0.0300 TIG hand welding torch WHL 240-H 013.6.0120 with manual gas valve, 8 m

5 Start Up

5.1 Installation of the Machine

Place the machine at least 0.80 m from a wall etc. to guarantee the cooling air can go through the unit. The room temperature should not exceed 40°C.

The room were the unit is placed should have a low degree of humidity (max. 50 % at 40°C, max. 90 % at 20° C).

The unit has passed the quality control in accordance with IP 21. When operating in places with high humidity, an additionad filter must be mounted (IP 23).

The air in the surroundings must be free from extreme quantities of dust, free from acides and corrosive gases etc. Otherwise use air filters .

5.2 Main Supply

The main supply must be connected by a trained person. The main supply voltage is displayed on the front or rear panel of the machine. A connection to ground (GND) must be done.

5.3 Connection of the welding cables

Operation mode: electrode Choose the correct polarity according to the type of electrode by plugging in the work piece cable and the cable of the electrode. Units with the mounted option “polarity switching“ do not need a change of the welding cables. The polarity is switched at the TEDAC-handshield.

5.4 Earth Lead (Work Cable)

The earth lead must have an excellent ground. The clamp should be attached to a clean, paint and rust free area on the work piece or on the welding table.

5.5 Operation mode: TIG

Plug in the TIG torch and the work piece cable to the plus pole bush. Connect the gas hose of the TIG torch to the gas regulator. Adjust the gas quantity as desired and ignite the arc by making a contact between torch, electrode and the workpiece (Lift Arc)

5.6 Operation with the unit connected to a generator

Consider the following comments:  The power of the generator must be at least 10% higher than the power of the welding

unit.

 The generator´s outcoming voltage must be stabilized in the no load voltage mode as well.  Due to possible peaks of the generator when switching ON, the welding unit should be

switched ON afterwards.

5.7 Cable prolongations

Only use non damaged prolongation cables with the correct sections.

 Do not work with looped cables  Overloading due to heat!  When using extremely long cables the welding output is reduced.

In this case encrease the sections of the cable.

5.8 Transport

If a transport by crane is required, the unit must be fixed at all lifting eyes.

6 Generalities of the welding unit Model E 420 DC

The welding unit E 420 DC is based on inverter technique and suitable for MMA/stick electrode welding. Continuous setting of the welding current up to 420 A.

The unit can be characterized by numerous features:

 inverter power source with continuous setting of the current 5-420 A  socket for remote control  digital read out with pre-display and hold-function  stick electrode operation:

1. Arc force: increasing of the welding current in order to avoid adherence of the electrode.

2. Hotstart function: increasing of the start current to assure a safe ignition.

3. Anti stick function: In case of adherence of the electrode, the current is switched off immediately. Re-ignition after separation only is possible with a short retardation.

6.1 Cooling of the power modul

The fans which are cooling the power modul are switched on automatically as soon as the arc is enlighted.

6.2 Electronics

The electronic is divided in to 3 sections:

 Display, selection of the logic and the operation mode  Adjusting and program parameters  Supervision of the temperature, fan control

6.3 Electrode Holder

Only use electrode holders with a proper insulation and a good contact with the electrode.

6.4 TEDAC-System

The TEDAC-System offers the possibility to adjust the energy from min. to max. by means of a slide switch (mounted at the hand shield ). The poti „energy“ is limiting the range of the welding current. The multi-coloured LED at the handle inside the shield shows the actual setting of the welding current. red - max. energy

green - min. energy

7 Current Adjusting

The welding current depends on the stick electrode and the diameter Formula: ca. 40-50 A/diameter of electrode in mm

Diameter of electrode 2,0 2,5 3,25 4,0 5,0 6,0 (mm) Current (A) 40-80 60-100 90-150 140-180 170-240 250-300

For further details see instructions of the relative electrode you are using.

Front panel of the E 420 DC

SCHWEISSTROM

welding current

HOTSTART - STROM

current

STROMNACHREGELUNG

arc force

HOTSTART - ZEIT

timer

TEDAC

HOLD

100

120

140

160

180

200

220

240

260

280

300

320

340

360

380

400

420

A %

120

130

140

150

160

170

180

190

200

0.2

0.4

0.6

0.8

1.0

1.2

5 6 7 8 9 10 11 12 13

8 Operation of the unit E 420 DC

1. Socket – Electrode cable with holder

2. Socket – Workpiece cable

3. 10-pole socket for remote control or the setting by the TEDAC-System the welding shield

4. Main Switch

5. LED failure: “overheating” – unit is dirty or the duty cycle has been passed, or “over voltage”- supply voltage higher than 440 VAC, or “under voltage”- supply voltage lower than 360 VAC

6. LED (yellow) thermal protection

7. LED (green) mains ON

8. Potentiometer welding current 5A...420A

9. LED (green) Hold

10. Digital read-out for the welding current with HOLD function It shows the welding current during the welding process. After the welding process the HOLD-LED is enlighted and shows the last value of the welding current. (no pre-indication of the real welding current)

11. Potentiometer HOTSTART-current 115%...200% of the potentiometer current

12. Potentiometer HOTSTART-time 0.01s...1,2s

13. Selector welding operation mode

13.1 electrode plus-pole: plug in the cable with the electrode holder to the bush electrode, Potentiometer current at the unit works

13.2 electrode minus-pole: plug in the cable with the electrode holder to the bush electrode,

Potentiometer current at the unit works

13.3 Electrode: Set of the polarity by the remote control,

Potentiometer at the remote control works. The potentiometer current at the machineis limitating the max. value

13.4 Electrode: the polarity can as well be set by the switch at the TEDAC-shield

TEDAC-slide switch works (increasing or reducing the energy), The poti current is limitating the max. value

13.5 TIG minus-pole at the torch (bush-work piece): Liftarc, (no torch trigger),the poti

current at the machine works, Hotstart andArc Force are out of function

13.6 TIG, minus-pole at the torch (bush- work piece): Liftarc, (no torch trigger),

manual remote control activated, the poti current is limitating the max. value Hotstart and Arc Force are out of function

14. Potentiometer ARC-FORCE 1..10 (250%)

avoids adherence of the electrode on the work piece: Rutil electrode: setting of the Arc Force between 1..3 Basic electrode setting of the Arc Force to 5 Cellulosic- electrode: setting of the Arc Force to 10

9 Cleaning

IMPORTANT: !!! Before opening the machine, disconnect it from mains !!!

Open the side covers. Remove dust from all parts of the machine.

Blow away the dust at the pcbs of the inverter withcompressed air –reduced pressure (appr. 0,5 – 1 bar). We recommend to clean the unit in regular periods.

10 Maintenance and Accident Prevention

The maintenance of the welding machine consists of a regular cleaning and inspection. It depends on the environment of the working area and the working hours. The machine should be cleaned in regular intervals to guarantee a proper operation. The length of the cleaning interval depends on the operation time, surrounding atmosphere etc.

ATTENTION: Before opening the welding machine, make sure

that it is disconnected from the mains supply. Wait for components to be sufficiently cooled down !

Wait until the capacitors are discharged (appr. 3 min.)!

11 Trouble Shooting

LED "mains ON" (green) does not go on after switching on the machine Check main supply Check main fuses

LED "failure" (red) is on Supply voltage too low or too high

LED "failure" (red) goes on for a short time Safety cut off device for primary current protection is activated: Switch off and after aprox. 3 s switch on again.

LED "Temp. protection" (yellow) and LED "failure" (red) are on unit is dirty or the duty cycle has been passed, Too high temperature at the transformer or IGBT-body: Let machine cool down.

Machine has no or too low welding current Check main supply of the welding unit (fuses) Bad or no contact of the welding leads Poor welding quality wrong adjustment of voltage trim Oxydated material

12 Partlist and wiring diagram

12.1 Partlist E 420 DC

electr. Description part no.

A1 Pc-board ME-I-PG-1.0 003.0.0001 A2 Pc-board ME-I-PI-1.0 003.0.0002 A3 Pc-board Pc-board ME-I-SD-1.1B 003.0.0003 A4 Pc-board Pc-board ME-EMV-3.1 102281 A5 Pc-board ME-NF400/2.5 102279 A7 Pc-board ME-I-RC-1.1 003.0.0004 A9 LEM-converter 010.0.1615 A11 Pc-board ME-ELREG-1.4 003.0.0027 A12 Pc-board ME-DISP-1.4 003.0.0044 A13 Pc-board ME-ELTEDAC-1.4 (Option) 003.0.0047 A15 Pc-board ME-UMPOL-1.4 (Option) 003.0.0050

C1 capacitor 0,1 µF/1000V 001.0.0415 C2 capacitor 0,1 µF/1000V 001.0.0415 C3 capacitor 5 nF/250V 003.0.5093 C4 capacitor 0,1 µF/1000V 001.0.0415 C5 capacitor 5 nF/250V 003.0.5093

A1/F1 fuse 0,2 A, slow at Pc-board ME-I-PG-1.0 A1/F1 fuse 0,2 A, slow at Pc-board ME-I-PG-1.0 A1/F3 fuse 0,2 A, slow at Pc-board ME-I-PG-1.0 F4 fuse 4 A, slow control transformer prim. 400 V 00301251 F5 fuse 4 A, slow control transformer prim. 400 V 00301251 F6 fuse 10 A slow control transformer sec. 42 V 00301199 F7 fuse 1 A slow control transformer sec. 42 V 00301212 F8 Termical switch 80°C opend 00100406

K1 contactor EH90-30-22 (GJD8230310R0103) (Option) 020.1.1510 K2 contactor EH90-30-22 (GJD8230310R0103) (Option) 020.1.1510 K3 contactor EH90-30-22 (GJD8230310R0103) (Option) 020.1.1510 K4 contactor EH90-30-22 (GJD8230310R0103) (Option) 020.1.1510

L1 choke (ferrit) 001.0.1992

M1 fan 230 V-AC at the Inverter 001.0.1323 M2 fan 230 V-AC at the Inverter 001.0.1323

Q1 main switch HLT 40 001.0.0014

R1 resistor 0,02 Ω/50W 030.0.4580 R2 resistor 330 Ω/50W 030.0.4583 R3 resistor 330 Ω/50W 030.0.4583

electr. Description part no.

R10 resistor 330 Ω/50W 030.0.4583 R15 NTC- resistor at the cooling body to IGBT 47 kΩ 010.0.1933 R17 resistor 39 Ω/50W 030.0.4584

T1 Ferrit- main transformer 001.0.1990 T2 control transformer MT400-500 003.0.0240 T3 converter 020.1.1124 T4 converter 020.1.1124

V1 rectifier-modul 001.0.0287 V2 rectifier-modul 001.0.0287 V3 rectifier-modul 001.0.0287 V4 rectifier-modul 001.0.0287 V5 rectifier-modul 001.0.0287 V6 rectifier-modul 001.0.0287

X1 bush 70/95mm² 500A 00101102 X2 bush 70/95mm² 500A 00101102 10-pol. socket for remote control 02110386 (Option remote control or Hand shield with TEDAC function) 10-pol. plug (acessories) 02110383 strain relief (acessories) 02110388

12.2 Wiring diagram E 420 DC