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MMA "Stick" Welding: What is Open Circuit Voltage (OCV) ?
What is OCV?
Open Circuit Voltage (also known as no-load voltage) is the voltage that exists between the electrode and the job (or the earth) when welding is not in progress.
What impact does OCV have on Stick welding performance?
OCV works in a similar way to Hot Start function in that a “higher” OCV improves the ease of electrode ignition (and also helps to maintain a strong/stable arc), which is especially advantageous when using difficult-to-run electrodes such as low hydrogen.
Broadly speaking;
Machines with an OCV of less than 50V will have "average-to-poor" arc characteristics. Many older transformer machines (especially single-phase) typically have an OCV of 40-45V. While these machines are OK for using with general-purpose electrodes, they can struggle to run electrodes such as low-hydrogen, some types of stainless, hardfacing and other more specialised rods that need a higher OCV.
Machines with an OCV of 50V & above will offer "good" arc characteristics. Most reputable inverter stick/MMA welders have an OCV of 50V or more.
Machines with an OCV of 55V & above will offer "great" arc characteristics. This category includes Weldclass machines such as the 140ST & 180ST.
Machines with OCV of 65-80V & above will offer "excellent" arc characteristics. This category includes Weldclass machines such as 135ST, 136S, 205MST & 255MST, 290MST.
How is OCV different from Welding Voltage?
OCV should not be confused with Welding Voltage. Welding voltage is the voltage that exists between the electrode and the job (or the earth) during welding, and this is what maintains the arc between the electrode and the job.
Welding voltage will typically be much lower than OCV, and will vary with many parameters (such as arc length, etc.).
More articles on MMA / Stick Welding
The MMA / Stick welding process
What is Hot Start, Arc Force & Anti-Stick?
Using Generators to power Inverter Welders
Welding electrode drying ovens
The benefits of twin-coated electrodes
Why you will never get a good weld with a bad earth clamp
While all care has been taken, Weldclass accepts no responsibility for any inaccuracies, errors or omissions in this information or links and attachments. Any comments, suggestions & recommendations are of a general nature only and may not apply to certain applications. It is the sole responsibility of the user and/or operator to select the appropriate product for their intended purpose and to ensure that the product selected is capable of performing correctly and safely in the intended application. E.&O.E.