Manuals / Lincoln Electric / Power Tools / Welding System

Lincoln Electric NA-5NF, NA-5SF Cold Start Circuitry, Auto Stop, Electrode Backup

Models: NA-5S NA-5N NA-5SF NA-5NF

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OPERATING INSTRUCTIONS

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In some cases, it is also possible to hold the “Actual” button pressed while starting the arc. Before the NA-5 shuts down, the actual arc voltage can be read on the digital meter. Comparing this reading to the “Set” reading will tell what change in the range controls of the power source are required so it can supply the desired voltage. Should the meter read zero, check the NA-5 sensing leads (#21 and #67) connections. Should the meter read negative (-) voltage, the polarity connections or settings at the NA-5 or power source are wrong.

This same general procedure can be used on the other power sources. For example, if the NA-5 keeps shutting down and the other possible causes have been checked, adjust the “Set” voltage higher and/or lower than the desired voltage. If the NA-5 continues to weld at one of these voltages, it can be determined what change in the range controls of the power source are required so it can supply the desired voltage.

COLD START CIRCUITRY

NA-5 controls above Code 8300 contain circuitry added to the voltage PC board to facilitate the “cold starting” features of these units.* This circuitry senses the voltage present between the electrode and work, via leads #67 and #21, and permits normal wire feed if this voltage exceeds approximately

6.5VDC. However, if this voltage level is not exceeded, or drops below approximately

3.5VDC, the “Auto Stop” activates while inching down or electrode backup occurs if the arc start circuit has been initiated.

*Units below Code 8300 can be provided with the cold start circuitry by replacing the old L-6257 voltage board with the new G-1556 voltage board. This new board will mount and connect in the same manner as the old board, except the third harness connector (previously connected to a jumper plug) must be connected to the lower receptacle of the new voltage board.

NOTE: HI-FREQ starting cannot be used with converted units below Code 8300.

A. Auto Stop

When the “Inch Down” button is pressed, a low-level DC voltage signal is applied between the electrode and work which permits the wire to inch down normally. When the electrode makes electrical contact with the work, it shorts out this signal causing the wire feed to automatically stop and the flux solenoid to activate until the “Inch Down” button is released. The “Inch Up” button is not affected by this circuit.

B. Electrode Backup

If while starting or welding the electrode stubs or shorts to work, the resulting loss of arc voltage will cause the electrode to momentarily back up until the arc voltage is re-established and then change back to the normal feed direction.

NOTE: The “cold starting” circuitry will cause the NA-5 to feed in the wrong direction when the “Start” button is pressed if the “Actual” arc voltage, as read on the NA-5 voltmeter, does not exceed typically about 6.5 volts. Usual causes for the situation are:

1.No wire loaded through the NA-5 head and nozzle assembly (except when using the K148 Contact Nozzle).

2.No power source weld cable connection to the NA-5 head or work.

3.Incorrect electrode polarity connections at the NA-5 or power source.

4.Little or no output voltage from the power source.

5.An open voltage sensing lead #67 or #21 to the NA-5 control box or a blown 1/8 amp fuse on a voltage PC board built since 1983.

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NA-5

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Lincoln Electric NA-5NF, NA-5SF service manual Cold Start Circuitry, Auto Stop, Electrode Backup
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NA-5S, NA-5N, NA-5SF, NA-5NF specifications

The Lincoln Electric NA-5NF, NA-5SF, NA-5N, and NA-5S are advanced welding helmets that are pivotal in enhancing the safety and efficiency of welders in various applications. These models are designed to provide exceptional protection and visibility, making them indispensable tools in the welding industry.

One of the main features of the NA-5 series is the auto-darkening filter technology. This feature allows the helmet to automatically adjust its shade based on the intensity of the arc. As the welder strikes an arc, the lens darkens instantaneously, shielding the eyes from harmful rays generated during the welding process. This functionality not only ensures safety but also enhances productivity, as welders do not need to manually flip the helmet up and down.

The helmets are equipped with a wide viewing area that allows for better visibility and precision while working. With a large lens, welders can easily monitor their work and surrounding environment, minimizing the risk of accidents. Additionally, the lightweight design of the NA-5NF, NA-5SF, NA-5N, and NA-5S provides comfort during extended periods of use, reducing neck strain and fatigue.

The NA-5 series is also well-regarded for its durability. Constructed from impact-resistant materials, these helmets can withstand the rigors of demanding work environments. This durability extends the lifespan of the helmet, making it a cost-effective investment for both professional and hobbyist welders.

Another notable characteristic is the adjustable sensitivity and delay settings found in certain models. These settings allow the user to customize the helmet based on their specific welding conditions. For instance, a welder can increase sensitivity for low-amperage tasks or adjust the delay to allow for a smoother transition from dark to light after completing a weld.

Furthermore, the helmets come with a reliable battery life, ensuring that they can be used for long periods without interruption. Some models also feature solar assist functionality, which helps recharge the auto-darkening filter, enhancing their overall efficiency.

In summary, the Lincoln Electric NA-5NF, NA-5SF, NA-5N, and NA-5S welding helmets represent a significant advancement in personal protective equipment for welders. Their combination of auto-darkening technology, wide viewing area, lightweight design, durability, and customizable settings makes them an excellent choice for anyone engaged in welding tasks. With these helmets, users can achieve greater safety and efficiency in their work, enabling them to focus on their craft with peace of mind.