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Hey guys . Was doing some welding thisevening and statrted having troubles. Machine has always welded in this shop and never had a problem . Thisevening i make a few passes boxing in some shackle towers and it works quiet and smooth as should be expected. I shut it off , make some gussets and go over to start welding again , i turn it on , adjust the wire feed control and as soon as i pull the trigger it makes this horrible buzzing noise inside the box , actually sounds like the feed motor is bussing alot louder than it ever has before but im not sure if its the motor or not . Anyways if you hold the trigger down for about 5 seconds it will throw the breaker in the shop , everyttime , sometimes all you have to do is quickly pull thr trigger and it will trip the breaker , cant see anything obvious , seeing if anyone else here has had this problem.
Reply:ok , was messing around with it thisevening. Actually got it working , but now it just doesnt have the heat it should , will not penetrate on any setting , just globs up . There is no where near the heat there that should be . Any ideas >
Reply:You may have had a shorted diode or two and now it has gone open
Reply:Do you have a schematic of the welder that you can post? I don't know that specific machine, but I assume it is a tapped voltage machine.If you can post a schematic we can discuss options much more intelligently. I went to www.lincolnelectric.com but couldn't find a manual. Try calling their technical support department and see if you can obtain a schematic.What did you do to get the machine "working" again? That might give us a clue.Low current capability might be related to open diodes or shorted turns in the transformer. If it is easy to non-destructively disconnect one output lead from the transformer AND disconnect power to the motor feed control board, one test would be to apply power, pull the gun trigger, and see if there is excessive current draw from the line observed with a clamp-on current meter on the input line, abnormal buzzing sound, opened breaker, or excessive heating of the transformer or the diodes. I would guess that more than a couple of amps at idle might indicate shorted turns in the transformer. Technical advisors at Lincoln might be able to tell you what idle current to expect. You might also tell them all your observations and ask if they have any advice.If you have a DVM or multimeter, measure forward and backward resistance across each diode while the transformer is disconnected. This is not the best diode test due to the low test current, but it will reveal fully shorted or open diodes. You should see low resistance in one direction and essentially infinite resistance in the other direction on each diode. You can test the diodes in the full bridge, but not with both transformer leads connected to the bridge (one is OK) and not with any external load on the bridge DC output.If everything seems OK, reconnect the diodes, turn on the machine, pull the trigger, and observe what happens (with the motor control board still disconnected). Shorted diodes would reveal themselves pretty quickly, but open diodes would not in this test. Welding with an open diode could cause excessive current draw from the power line due magnetic saturation of the transformer but should cause no symptoms while not welding. However, the fact that you observe breaker tripping without actually welding tends to indicate that open diodes are not the problem.Sniff around the transformer for any acrid burnt insulation smell. Let the machine idle with the trigger pulled and with the motor control board disconnected. Look for signs of overheating. After ten minutes or so turn the machine off, PULL THE PLUG, quickly discharge any large capacitors present with a low value resistor between two probes, THEN feel around for overheated components. If you don't have any low value resistors, use a 60 or 100 watt incandescent lamp in a socket with flying leads.Good luck.awrightLast edited by awright; 04-12-2009 at 11:24 PM. |
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发表于 2021-8-31 22:23:56