OCV problems

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How’s it going y’all?I have a 2008 Lincoln 300D giving me some issues. In the morning when I turn the machine on the OCVs are at 101 and a few hours later they’re at 84 or so. Anybody have any idea why they’re dropping so much? Sent from my iPhone using Tapatalk
Reply:There is an adjustment I believe for OCV at least it talks about it in the manual.  I would check that 1st, see if anything is loose or worn out which is causing things to change as the machine warms up.
Reply:

Originally Posted by Weld_

There is an adjustment I believe for OCV at least it talks about it in the manual.  I would check that 1st, see if anything is loose or worn out which is causing things to change as the machine warms up.
Reply:As Weld suggested, check to "see if anything is loose or worn out" such as all coarse amperage selector switch cable connections, coarse selector switch contacts, both output stud cable connections (both sides) and fine voltage rheostat windings for corrosion or just general dirtiness.That said, a drop in OCV from cold to warmed up condition is normal but loose/dirty connections = resistance = heat = more resistance = voltage drop across suspect connection.Also, I presume you're checking OCV at the weld output studs but if at the working end of your weld leads, the same applies with regard to loose/corroded connections and in severe cases the overall condition of your weld leads.Have you confirmed the unit is operating at the correct high idle speed?MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110

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Reply:I would check the voltage using a load resistor. This can as simple old fashion light bubs at less 200 watts. Dave

Originally Posted by Raul250

How’s it going y’all?I have a 2008 Lincoln 300D giving me some issues. In the morning when I turn the machine on the OCVs are at 101 and a few hours later they’re at 84 or so. Anybody have any idea why they’re dropping so much? Sent from my iPhone using Tapatalk
Reply:

Originally Posted by duaneb55

As Weld suggested, check to "see if anything is loose or worn out" such as all coarse amperage selector switch cable connections, coarse selector switch contacts, both output stud cable connections (both sides) and fine voltage rheostat windings for corrosion or just general dirtiness.That said, a drop in OCV from cold to warmed up condition is normal but loose/dirty connections = resistance = heat = more resistance = voltage drop across suspect connection.Also, I presume you're checking OCV at the weld output studs but if at the working end of your weld leads, the same applies with regard to loose/corroded connections and in severe cases the overall condition of your weld leads.Have you confirmed the unit is operating at the correct high idle speed?
Reply:Having this exact problem checked ocvs at 104 made 4 12inch welds was down to 92. Machine is idling at correct rpm range and the rack is on the factory punch mark
Reply:

Originally Posted by Tuck10

Having this exact problem checked ocvs at 104 made 4 12inch welds was down to 92. Machine is idling at correct rpm range and the rack is on the factory punch mark
Reply:I'm aware of that this is much more severe heat loss than anything I've experienced. Another guy on the job has an identical machine both are at factory settings in regards to idle speed and rack. His machine holds heat all day
Reply:Does the auxiliary power OCV drop off as well in the same time frame?  If yes, I'd look at the auxiliary power/exciter side of the machine.Here's the troubleshooting points from the manual to check out when a "Machine fails to hold the output (heat) consistently.":1. Rough or dirty commutator.2. Brushes may be worn down to Limit.3. Field circuit may have variable resistance connection or intermittent open circuit due to loose connection or broken wire.4. Electrode lead or work lead connection may be poor.5. Wrong grade of brushes may have been installed on generator.6. Field rheostat may be making poor contact and overheating.I'd take a close look at the field rheostat windings/wiper brush and the field bridge rectifier (mounted to backside of control panel) terminal connections.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110

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