If the TX or machine is growling or has excessive or more than normal vibration it could be from either a loose bolt or half cycling. Half cycling is not good and the machine should be shut down. When a machine is half cycling the TX is not getting both sides of the A/C current. Therefore, the TX will soon saturate and will not give enough voltage for welding. If this happens, the TX will need to be replaced and this will cause a lot of down time. It could also become a safety issue if the TX shakes so much it shorts through to the secondary and high voltage is exposed. Because of this, the TX should be properly grounded so that the breaker or fuse will be tripped.
Transformer (TX) half cycling can come from, or be caused by, a bad SCR, bad firing board, or a bad controller/timer. If your controller/timer is over twelve years old then replace the entire unit. Do not waste production time trying to figure out which component has gone bad. This is simple common sense because production up-time is worth more than the time to trouble shoot the components and most units can be replaced in less than 24 hours.
You will also need to complete the TX check to make sure the TX has not become saturated.
Click here to see the Sheets for trouble shooting SCR and TX as a Web Page. (recommended)
Click here to see the Sheets for trouble shooting SCR and TX as a word document.
An arcing noise at the weld can normally be fixed by increasing the squeeze time by five to ten cycles. If the arcing is someplace else then it is most likely a loose bolt that should be re-tightened. This sometimes happens in the tap switch so you might want to try that area first. Be careful and safe anytime you are inside the machine frame because there is usually high voltage present.
Hissing sounds are from air leaks which would lead to pressure drops and
possibly arcing noise. Air is not free so fix the leak. If the leak is in the
cyclinder then the cylinder seal or o-rings should be changed. Often it is
cheaper to change-out whatever is leaking.
| Yes | No | Back | More Info Needed - send email |