common faults and maintenance of electric motor of crusher
Electric motor fault often affects production when crusher is running, the main faults are:
Fault Maintenance of Motor Stator & Rotor Core:
Motor stator and rotor core is made of stripe of mutually insulated silicon steel sheets, it is the magnetic circuit of electric motor. Damage and deform of motor stator and rotor core is caused by the following reasons:
① Over worn of bearing or improper assembly causes motor stator and rotor core rub again each other, damage on the surface of core, further causes short circuit between silicon steel sheets, core loss increasing, and high temperature rising of electric motor. At this time, smooth file, or other tool is used to remove burr and short connection of silicon steel sheets, insulating varnish is coated after cleaning up, heated and drying.
② To remove old winding with great force, causes groove tilt and splay out. Needle nose pliers, wooden hammer and other tools should be used to repair, and reset the bad teeth. Hard fiber paper, Bakelite plate and other hard insulating material should be added to silicon steel sheets with gap.
③ Core is easy to rust in wet condition. At that moment, sandpaper should be used to be cleanly rubbed and then coated with insulating varnish.
④ Windings grounded generates high heat and burns down core grooves and teeth. Chisel or scraper and other tools can be used to completely remove the fused-deposition, coated with insulating varnish and to be dried.
⑤ If core and engine base fits is loose, original set screw can be tightened. If set screw is fail, you can drill another set hole on engine base and thread tapping, and then tighten the set screw.
Faults and Maintenance of Bearing:
Revolving shaft supports rotation through bearings, it is the part that carries the greatest weight, also the component that is easy to wearing.
Checking in operation ；
When roller bearing is in shortage of oil, you can heard the sound of “Gulu Gulu”; If discontinuous sound of “Geng Geng” is heard, it is probably crack on the steel ring of bearing. If there is sand or other substance in bearing, or slight wearing, light noise will be occurred.
Checking after disassembly；
Bearing rolling element, inner and outer steel ring should be firstly inspected for damage, rust, scar, and so on., and then hold the inner steel ring of bearing by hand to make the bearing even, push hard outer steel ring by another hand. If bearing is good, outer steeling ring should be stable rotated, and there is no obvious vibration and clipping phenomenon while rotating, and no step backward phenomenon of outer steel ring when stops rotating, otherwise it means the bearing cannot work. Stuck outer steel ring by left hand, hold inner steel ring by right hand, push hard towards all directions. If it feels loose when pushing, it indicates the bearing is heavily worn.
00# sandpaper can be used to rub off the rust-spotting on bearing surface, put it into petrol for cleaning; If there is flaw on bearing, crack on inner and outer steel ring or excessive wear on bearing, bearing should be changed to a new one. Same size of bearing should be chosen for bearing change.
Fault and Maintenance of Revolving Shaft:
If shaft is not too bend, it can be repaired with polishing bearing journal and slip ring, etc: If bending is not exceed by 0.2mm, revolving shaft can be placed under pressing machine to pressurize and correct the bend, after correcting, axis surface is cutting and polishing with lathe; If it is too bend, a new axis should be changed.
②Bearing Journal Abrasion；
If bearing journal abrasion is not great, chromium can be coated on bearing journal, and cut it to the right size; If abrasion is too much, wielding on bearing journal can be carried on, cut and polish with lathe; If bearing journal is over abrasion, 2-3mm bearing journal should be cut, and then made another set of barrel, stretch it onto bearing journal while barrel is hot, and then turning it to the specified dimension.