- Thread starter HANCYM
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jugs
Dont wish to offend & annoy, but...
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Drains
Yeah, nah.
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How is that achieved
They use Magic, Jugs
.You can google it to your hearts content (I did), and still not know how, only why. An MMA supply has a "drooping" characteristic. I know how it feels.
shenion
Tool Pack Rat
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Constant voltage is easy, just a transformer tap and a rectifier. A different tap is needed for each voltage.
MMA is not really constant current. It has a specific voltage/current slope for a given output. This is normally done with a variable inductor on the AC side that controls the current. This can be done with a sliding core to vary the inductance or via a control winding that saturates the core.
MMA is not really constant current. It has a specific voltage/current slope for a given output. This is normally done with a variable inductor on the AC side that controls the current. This can be done with a sliding core to vary the inductance or via a control winding that saturates the core.
jugs
Dont wish to offend & annoy, but...
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Thanks Scott, that all makes sense 
There you go Si, snot magic after all.
You move your core in & out of the middle of the inductive girdle until you reach the perfect saturation point for your given output, ending in a "drooping" characteristic.
This is often accompanied by loud humming & shaking, depending on which model you are using, this maybe age dependent as older models are usually better built.
There you go Si, snot magic after all. You move your core in & out of the middle of the inductive girdle until you reach the perfect saturation point for your given output, ending in a "drooping" characteristic.
This is often accompanied by loud humming & shaking, depending on which model you are using, this maybe age dependent as older models are usually better built.
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It must be inverter MMA welders that use magic (electrickery) then
shenion
Tool Pack Rat
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Yes, has micro processor to watch voltage/current and vary the PWM that drives the output.
My home-built genny welder is half smart. Has processor to control but uses digital potentiometers to set voltage and current slope. For MIG, set the current droop to 0 and the desired voltage (constant voltage). For arc, set max voltage and adjust the droop to set the current.
For example open voltage is 50V. Weld at 25V at 50A. Set slope at 1/2 volt per amp. So at 50A it drops 25V down to the desired voltage.
Sounds complicated, but I just turn the knob until the rod burns at the desired rate
Never really know what the value is.
My home-built genny welder is half smart. Has processor to control but uses digital potentiometers to set voltage and current slope. For MIG, set the current droop to 0 and the desired voltage (constant voltage). For arc, set max voltage and adjust the droop to set the current.
For example open voltage is 50V. Weld at 25V at 50A. Set slope at 1/2 volt per amp. So at 50A it drops 25V down to the desired voltage.
Sounds complicated, but I just turn the knob until the rod burns at the desired rate
Never really know what the value is. 