(4) Before using the welding machine, the following contents should be checked:
(1) The welding machine should be connected correctly, the current range should meet the requirements, the wire connections should be firm and reliable, the shell should be reliable grounding.
(2) check whether the fuse or fuse of the brake box is intact, whether the current regulation performance is intact.
Check whether there is foreign body inside the welder. Only when everything is normal can the switch be closed.
(5) When working, the welding core should not be strongly vibrated, and the screws that press the core should be tightened. Always check whether the temperature of welding machine and current regulator exceeds 60℃ (that is, the temperature that the palm can bear). When opening the lid for inspection, pull down the knife first. If the welder is overheated, wait for the welder temperature to drop before welding.
(6) Strengthen the maintenance work, keep the welder inside and outside clean, ensure the welder and welding flexible wire insulation is good, if there is any damage or burning should be repaired immediately.
(7) Add lubricating oil to the screw, nut and other parts of the current regulating device to ensure normal operation, and check whether there is any burning or other damage of each junction board frequently.
(8) Regularly check the technical condition of welding machine circuit by electrician.
(9) For new or long-unused welding machines, the insulation resistance between windings and the machine case should be checked with a table before use. If it is lower than 0.5 megohm, the welding machine should be dried to restore the insulation. Old equipment should also be checked frequently.
Use and maintenance of rotary DC arc welding machine
The contents in (1), (2), (3) and (9) of rotary DC arc welding machine are the same as that of AC welding machine. The contents to be checked before using the welder are as follows: first, check whether the wiring is correct, whether the polarity is right, whether the current range meets the requirements, whether the joint is firm and reliable, whether the shell is grounded reliably, etc. Second, check the inside of the welder to see if there are any obstacles to rotation. Third, check whether the fuse or fuse of the brake box is in good condition, and whether the current regulation performance is in good condition. Fourth, check whether the rectifier (commutation) color is normal, whether the surface is smooth, whether there are any defective marks and hard damage, whether the mica piece is higher than the surface of the rectifier, if any of the above phenomenon, it should be straightened immediately: the fine sandpaper is fixed on the surface of the wood block (this surface is the same as the arc surface of the rectifier), and ground. Carbon and copper dust from the rectifier shall be wiped off with a cloth impregnated with petrol. Fifth, check whether the brush surface is smooth, good contact with the rectifier, pressure is appropriate. In case of bad contact or brush damage and wear, repair or replace immediately. The new brush shall be ground with fine sandpaper to make it consistent with the rectifier's solitary surface. The brush of the new welder must also be ground before use. Sixth, the rheostat should be adjusted to the minimum position before starting, and the welding machine must be started under no load. Seventh, after starting, check whether the welding machine is turning correctly. If it turns that way, stop it immediately and correct the turning. The multi-head DC welder cannot be started directly, it should be started by "Y-△" starter. When starting, keep the "Y" connection for 20~30 seconds, and then access the "△" connection (or start with compensator) after the motor rotation is stable.
The rectifier and brush should be checked first when working. If vibration or spark is found to be abnormal in color and size (tiny specks with yellowish-green or dark red sparks are normal; A large number of spicules with red spark is abnormal, at this time the brush burns seriously; Green and white fire flowers and even ring flowers are dangerous), should stop immediately, inform the electrician repair. Next is to check whether there is noise rotation, if the sound is abnormal should stop for repair. Finally, check the heating condition of the coil. If overheating occurs soon after the operation, stop immediately for repair.