Kemppi Master S 400/500 Welding Machines

1. Introduction

Congratulations on choosing a Master S series power source. With proper operation, Kemppi equipment can significantly increase welding productivity and provide long-term economy.

This manual contains important information on the operation, maintenance, and safety of the equipment you have purchased from Kemppi. Technical specifications are provided at the end of the manual. Please read the operating and safety instructions carefully before using the equipment. For your own safety and to preserve the equipment, pay special attention to the safety instructions.

For more detailed information about Kemppi equipment, contact Kemppi Oy, your authorized dealer, or visit www.kemppi.com.

The technical specifications provided in this manual are subject to change without prior notice.

Sections requiring special attention to reduce the risk of equipment damage or personal injury are marked with the heading "ATTENTION!". Read these sections carefully and follow their instructions.

Disclaimer of Liability: While every effort has been made to ensure the accuracy and completeness of the information in this manual, the company is not responsible for any errors or omissions. Kemppi reserves the right to change the technical specifications of the equipment at any time without prior notice. Copying, recording, reproduction, or transmission of the contents of this manual is prohibited without the prior consent of Kemppi.

1.2 Equipment Description

Master S welding machines are designed for industrial use and welding with all types of coated electrodes. The Master S machines can also be used for carbon arc gouging.

In addition to basic functions, the Master S 400 and 500 models include advanced features such as HotStart, ArcForce, TIG mode, and remote control, which are adjusted via the control panel.

Both models are equipped with a Voltage Reduction Device (VRD) designed to keep the open-circuit voltage below 35 V.

The Master S 400 and 500 models also operate in Constant Voltage (CV) mode and serve as the primary power source for Kemppi wire feeders with sensing technology and for linear TIG welding solutions like ArcFeed and MasterTig LT 250.

In models for Australia and New Zealand, the VRD is always on and complies with AS/NZS standards and safety regulations for mining. The VRD features fail-safe functionality.

1.3 Brief Description of Equipment

Master S 400 and 500

The control panel includes the following elements:

1. Power ON indicator lamp
2. Overheat indicator lamp
3. CV mode indicator lamp
4. VRD indicator lamp
5. Ammeter display
6. Voltmeter display
7. ArcForce control
8. HotStart control
9. Remote control indicator
10. Welding mode selector
11. Current regulator
12. Negative (-) pole connection socket
13. Positive (+) pole connection socket
14. Main switch (On/Off)
15. Power cable
16. Remote control connector

The display cover is part of the standard equipment package for the Master S 400 and 500. It is designed to protect the panel from sparks, dust, and scratches.

2. Installation

2.1 Before Operation

The equipment is packed in specially designed boxes. However, before use, you must ensure that the equipment has not been damaged during transport.

Also, ensure you have received the ordered components and necessary operating instructions. The equipment packaging is recyclable.

ATTENTION! Always lift the welding machine by its handle when moving it. Never pull it by the welding cable or other cables.

Operating Conditions

This equipment is suitable for indoor and outdoor use. Ensure that the ventilation openings of the equipment are not blocked. The recommended operating temperature is from -20 to +50 °C.

Also read the safety instructions regarding operating conditions.

2.2 Equipment Placement

The equipment should be placed on a firm, horizontal, dry surface that prevents dust and other contaminants from entering the equipment through the cooling air streams. It is advisable to place the equipment on a suitable trolley so that it is elevated from the floor.

Notes on Equipment Placement

• The tilt of the base should not exceed 15 degrees.
• Ensure free circulation of cooling air. The clearance around the front and rear of the equipment should be at least 20 cm to allow for cooling air circulation.
• The equipment should be protected from heavy rain and direct sunlight. Operation in rain is not permitted, as the equipment's IP23S protection class only allows for conservation or storage outdoors.
• ATTENTION! Never direct sparks from a grinding machine towards the equipment.

2.3 Power Network

All standard electrical devices without special circuitry generate harmonic currents in the power network. High levels of harmonic current can lead to the failure or malfunction of some equipment.

Provided that the low-voltage power network's short-circuit power at the point of common coupling is greater than or equal to 4.8 MVA, this equipment complies with standards IEC 61000-3-11 and IEC 61000-3-12 and can be connected to low-voltage public power networks. The installer or user of the equipment is responsible for ensuring, if necessary in consultation with the grid operator, that the system's impedance is within the specified limits.

3. Operation

3.1 Welding Processes

3.1.1 MMA Welding

MMA welding, as well as carbon arc gouging, can be performed with any Master S power source.

3.1.2 Tungsten Inert Gas (TIG) Welding

TIG welding requires a separate TIG torch with a gas valve. Refer to the "Order Codes" section.

3.2 Operating Functions

3.2.1 Power Source

ATTENTION! Always switch the equipment on and off using the main switch. Do not use the power plug as a switch!

ATTENTION! Never look directly at the welding arc without a welding mask specifically designed for arc welding! Protect yourself and surrounding objects from the welding arc and hot metal spatter!

3.2.2 Control Panel and Setting Functions

WeldData

After welding is completed, the display will show the average current for the last weld. Welding data is displayed only if the welding cycle duration was at least 5 seconds.

Extended Control Panel

1. ON indicator: Green indicator shows the power source is on.

2. Overheat indicator: This indicator shows that the equipment is overheating.

3. CV mode indicator: This indicator shows that the equipment is in CV mode. The operating mode can be changed in the settings.

4. VRD indicator: This indicator shows that the VRD is active. If welding is not performed and the indicator is off, the VRD is inactive. Steady green: VRD is active. Off: VRD is active, but the unit is welding. Flashing red: VRD has stopped the unit's operation due to a fault.

ATTENTION! In AU models, the VRD function cannot be switched off.

5. Voltmeter display: Shows the voltage.

6. Current regulator: Turn the regulator to set the welding current.

7. Ammeter display: Shows the current used during welding and the set current when not welding.

8. ArcForce: Lower values make the arc "softer"; higher values make it "harder". Adjustment range: -9 to +9. The value is displayed on the right display when the regulator is turned. Factory setting: 0 (regulator points up).

9. HotStart: A setting of 0 means HotStart is not used; a setting of 10 means maximum HotStart level. The value is displayed on the right display when the regulator is turned. Factory setting: 5 (regulator points up).

10. Welding mode: Press to select TIG or MMA mode. The selected mode is indicated.

11. Remote control: Press to select remote control or control panel operation. The indicator shows the remote control selection. A long press (> 3 s) activates the setting function.

3.2.3 Activating and Adjusting Setting Parameters

1. Press and hold the remote control selection button (11) for at least 3 seconds until "Set" is displayed.
2. Select the desired parameter using the current regulator (6).
3. To select a parameter, press the remote control selection button (11). Each press of button (11) toggles between adjustment mode and selection mode.
4. Adjust the parameter value using the current regulator (6).
5. You can exit the setting mode by pressing and holding the remote control selection button (11). The settings are saved upon exiting the setting mode.

Setting Menu Structure

Constant Voltage (CV)

In CV mode, the welding machine maintains a relatively stable DC voltage regardless of the current. This mode is recommended for carbon arc gouging and MIG/MAG welding with Kemppi wire feeders with sensing technology. The CV function is activated in the settings menu.

Voltage Reduction Device (VRD)

Master S 400 and 500 units are equipped with a VRD that maintains the open-circuit voltage below 35 V. This reduces the risk of electric shock in particularly hazardous environments, such as confined or wet spaces. The VRD function is activated in the settings menu.

NOTE! In AU models, the VRD function cannot be switched off.

3.3 MMA Welding

In manual metal arc welding (MMA), molten filler metal transfers from the electrode to the weld pool. The nominal welding current is selected based on the electrode size and welding position. The arc is formed between the electrode tip and the workpiece. As the electrode coating melts, it forms gas and slag, which protect the molten metal during transfer to the weld pool and during solidification. The slag layer that forms on top of the hot weld metal prevents oxidation. The solidified slag layer is removed after welding, for example, with a slag hammer. When removing slag, eye and face protection must be worn.

For more detailed information, see www.kemppi.com > Welding ABC.

3.3.1 Consumables and Equipment

Master S units can use all common types of electrodes designed for DC welding. Electrode sizes for this machine are listed in the "Technical Specifications" section of this manual. Welding work conditions specified on the electrode packaging must be followed.

1. Ensure that the welding cable and ground cable connectors are hand-tight. If a cable connector is not tight, it can lead to reduced welding performance and overheating of the connector, and may void the warranty on your equipment.
2. Select the correct electrode type and secure it firmly in the electrode holder.

3.3.2 Ground Cable and Clamp

Whenever possible, always secure the ground cable clamp directly to the workpiece being welded.

1. Clean the contact surface of the clamp of paint, dirt, and rust.
2. Connect the clamp carefully, ensuring maximum contact area.
3. Finally, check that the clamp remains securely attached.

3.3.3 Manual Metal Arc (MMA) Welding

Select the required welding parameters according to the consumable manufacturer's recommendations and the characteristics of the weld seam to be performed.

1. Select the required polarity (+ or –) for the welding cable (typically +) and the ground cable (typically –) according to the consumable manufacturer's recommendations.
2. Select the MMA welding mode by pressing the welding mode selection button on the control panel.
3. Select the appropriate welding current using the current regulator.
4. Perform a small test weld to check if the parameters are set correctly.

Position the equipment in a suitable location, ensuring the cable length is sufficient for the welding pass. Before starting welding, ensure your position in front of the workpiece is comfortable and stable, with your weight evenly distributed.

Ensure the power source current setting matches the selected electrode size.

Protect your eyes with a welding mask. (Electronic welding masks, such as Kemppi Beta 90X, allow for more precise arc starting location and better focus on the welding process, reducing the risk of arc flash.)

ATTENTION! Ensure that other persons in the welding area are aware that you are about to start welding.

To ignite the arc, strike the electrode against the workpiece surface.

After igniting the arc, hold the welding electrode at a pulling angle. The edge of the formed slag should be visible behind the weld pool. It should be behind the weld pool boundaries. The distance from the slag edge to the weld pool can be adjusted by changing the welding current and the angle between the workpiece and the electrode. During welding, monitor the arc length and try to keep it as short as possible. The arc length may increase as the electrode length decreases during welding.

Finish welding by moving the welding electrode a short distance over the completed weld seam and lifting the electrode perpendicular to the workpiece.

The deposited bead of the weld seam should be straight and have a uniform width, height, and appearance along its entire length. If the travel speed is too slow during welding, the weld pool will become too large and may burn through the workpiece; too fast a travel speed results in a too-narrow seam, possibly with slag inclusions and/or low strength. After welding, the slag solidified on the surface of the seam should be easily removable with a slag hammer. When removing slag from the seam surface, always wear eye and face protection.

3.3.4 Electrode Welding Parameter Table

3.3.5 Arc Force

Adjusting the arc force using the ArcForce knob affects the arc stiffness. The factory setting for all electrode types is zero. Setting values from -9 to -1 make the arc "softer" and reduce spatter, especially when welding with current in the upper range of the recommended values for the electrode used. Setting values from 1 to 9 makes the arc "harder".

The value is displayed on the right display during adjustment.

3.3.6 Hot Start

The HotStart function temporarily increases the current to ignite the arc. For thin workpieces, hot start is generally not needed (depends on electrode type).

The hot start value is set from 0 to 10. A setting of zero disables the HotStart function (hot start is not used), and 10 sets the maximum hot start level. Factory setting: 5.

The value is displayed on the right display during adjustment.

3.4 Tungsten Inert Gas (TIG) Welding

ATTENTION! For TIG welding, the welding cable must be connected to the negative (-) pole connection socket, and the ground cable to the positive (+) pole connection socket.

Select the required welding parameters according to the consumable manufacturer's recommendations and the characteristics of the weld seam to be performed.

1. For TIG welding, select the required polarity for the welding cable (-) and the ground cable (+).
2. Select the TIG welding mode by pressing the welding mode selection button on the control panel.
3. Select the appropriate welding current using the current regulator.
4. Perform a small test weld to check if the parameters are set correctly.

DC TIG welding uses shielding gas. Your dealer can help you choose the correct gas and equipment.

Welding can begin after selecting the necessary parameters. Open the gas valve on the TTM 15 V BC torch. After gas flow begins, ignite the arc by touching the tungsten electrode tip to the workpiece, or by spot-touching (see "Spot-touch arc ignition in TIG welding"). After the arc ignites, maintain the tungsten electrode tip at the appropriate distance from the workpiece to regulate arc length. A suitable arc length is typically about half the diameter of the electrode wire. Move the torch forward from the starting point. Adjust the current value if necessary.

The filler wire, tungsten electrode, and welding current are selected according to the type and thickness of the base metal, the weld shape, and the welding position.

To stop welding, lift the torch away from the workpiece and close the gas valve on the torch.

ATTENTION! The torch will remain live.

ATTENTION! Always secure the gas cylinder in a stable vertical position on a special wall bracket or in a cylinder trolley. Always close the cylinder valve after welding is completed.

Spot-touch Arc Ignition in TIG Welding

TIG welding arc can be ignited by spot-touching. To ignite the arc, carefully touch the electrode to the workpiece and quickly retract it to the required distance. If the electrode contact with the workpiece lasts longer than 1 second, the power source's ignition circuit will automatically disable to prevent electrode damage.

To stop welding, quickly retract the electrode from the workpiece.

Information for ordering additional equipment (TIG torches) required for TIG welding is provided in the "Order Codes" section of this manual.

3.5 Carbon Arc Gouging

Constant Voltage (CV) mode is recommended for carbon arc gouging. In CV mode, voltage can be adjusted. Gouging is also possible in MMA mode. Voltage and current settings are shown in the table below.

3.6 Wireless Remote Control

In addition to the analog remote control, the Master S equipment also supports a wireless remote control. The wireless remote control is activated by selecting the remote control mode using the "Remote" button, followed by selecting "r11" (R11T wireless remote control) via the control panel's setting function.

The VRD must be switched off. The wireless remote control does not work when the VRD is active.

Using the wireless remote control:

1. Set the required welding current using the regulator on the remote control.
2. Touch the end of the remote control to the workpiece and simultaneously touch the electrode to the contact surface of the remote.

4. Technical Maintenance

ATTENTION! When performing maintenance on electrical cables, avoid exposure to mains voltage!

When planning technical maintenance for the equipment, consider its intensity and operating conditions. Adhering to operating instructions and performing preventive maintenance will help avoid disruptions to the production process and unplanned downtime. Check the condition of welding and connection cables daily. Do not work with damaged cables!

4.1 Periodic Technical Maintenance

4.1.1 Every Six Months

ATTENTION! Unplug the unit from the mains socket and wait approximately 2 minutes before removing the housing cover.

The following technical maintenance operations should be performed at least once every six months:

• Check the condition of the unit's electrical connectors; clean oxidized connectors and tighten loose ones.

ATTENTION! Before attempting to repair connections, find out the correct tightening torques.

• Remove dust and dirt from the internal parts of the unit using a soft brush and a vacuum cleaner. Do not use compressed air, as it may push dirt deeper into the radiator fins. Do not use a pressure washer.

ATTENTION! Repairs must only be performed by a qualified electrician with the appropriate certification.

ATTENTION! The unit and control panel are live. DO NOT remove the cover or control panel without authorization. Maintenance and repair must only be performed by trained personnel with appropriate certification.

4.2 Service Contract

Kemppi service centers offer customers special contracts for periodic technical maintenance. They perform cleaning, inspection, and, if necessary, repair of all components. The service center also verifies the normal operation of the welding machine.

4.3 Storage

The equipment should be stored in a clean and dry environment. The equipment must be protected from rain and direct sunlight in locations where the temperature exceeds +25 °C.

4.4 Equipment Disposal

ATTENTION! Electrical equipment must not be disposed of with regular household waste!

Electrical equipment that has reached the end of its service life must be collected separately and sent to an appropriate recycling facility that ensures environmental protection.

The equipment owner must send the decommissioned equipment to a regional collection center according to local authority instructions or a Kemppi representative. By following these instructions, you protect the environment and people's health.

5. Troubleshooting

All system errors will be displayed on the control panel. The display shows error codes, the descriptions of which are provided in the table below.

5.1 Troubleshooting

Power ON indicator lamp is not lit.

• The unit is not receiving power.
• Ensure the unit is connected to the electrical network.
• Check the mains fuses and replace any blown ones.
• Check the power cable and plug and replace faulty parts.

The unit does not provide the required welding quality. Spatter is formed during welding. The weld seam has pores, or the power supply is insufficient.

• Check the welding parameters and adjust them if necessary. Refer to the welding parameter table on page 10.
• Ensure the ground cable clamp is securely attached and the ground cable is not defective. If necessary, move the clamp to a different location and replace faulty parts.
• Check the condition of the welding cable and connector. Tighten the connection(s) and replace faulty parts.

Power source overheat indicator lamp is lit.

The power source temperature has exceeded the maximum permissible operating temperature. The fans are running, and the unit is in cooling mode. The unit will recover automatically.

• Ensure there is sufficient clearance around the unit for cooling air circulation.

In some cases, the unit will shut down upon encountering an error. The operator must switch the main switch off and then back on again.

• Ensure the welding circuit is open.

5.2 Error Codes on the Control Panel

6. Order Codes

7. Technical Specifications