Author: Radoje Jankovic

Photos from my friend, Goran Miloradovic.

INTRODUCTORY EXPLANATIONS

Likeand always, I will not deal with theory, because there are thousands and thousands of theoretical works and articles about electric motors on the Internet, so they have become few and boring. Just, everyone who masters one type of rotary electric machine at school or university immediately wants to write lessons, lectures on that topic without having seen many types of these motors in practice, and especially since almost not a single electric motor has been disassembled into all parts and reassembled assembled it, not to mention that he has ever disassembled electric motors that were burnt, severely damaged or damaged during exploitation in the most varied operating conditions.

In AC and DC collector electric motors, which are widely used today for all kinds of electric tools, devices and various appliances, both in households and in industry, the rotors are the most frequently damaged. My friend Goran, an expert winder of almost all kinds of electric motors, made an effort to photograph in his workshop the entire process and every working operation of winding the collectors rotor of two small single-phase AC electric motors, and the same work procedure is used for small direct current motors that are used for the most diverse device, machines and apparatus.

In total, he took 40 excellent, very clear photos of all the work operations. Of course, it was not necessary here to show the ways of cutting the insulation for the rotor grooves, as well as just disassembling and removing it from the machine it drives.

NOW,

Let’s get to work!

Slika 1. Dva neispravna rotora kojima su stradali namotaji …
Figure 1. Two faulty rotors with damaged windings…
Slika 2. … prvi korak je detaljno snimanje podataka o svakom rotoru…
Figure 2. … the first step is to record detailed data about each rotor…
Slika 3. … sečenje namotaja rotora na malom strugu za obradu metala…
Figure 3. …cutting a rotor winding on a small metalworking lathe…
Slika 4. … jedna i druga strana se odsecaju …
Figure 4. … one and the other side are cut off …
Slika 5. …  radna operacija skidanje kolektora sa rotora …
Figure 5. … working operation of removing the collector from the rotor …
Slika 6. … Izbijanje žice iz žlebova rotora …
Figure 6. … Breaking the wire out of the rotor grooves …
Slika 7. … ponekada ide lako izbijanje žice, bez potrebe za grejanjem…
Figure 7. … sometimes it is easy to break out the wire, without the need for heating…
Slika 8. … telo – jezgro rotora izrađeno od štancanih magnetnih limova bez žice…
Figure 8. …  rotor core made of stamped magnetic sheets without wire…
Slika 9. … ponekad se mora dobro zagrejati i spaliti kako bi se lakše izvadila žica iz žlebova rotora…
Napomena: Kod zagrevanja plamenom jezgro rotora koje je izrađeno od laminiranih magntnih limova koji se koriste za izradu jezgra rotora se zagrevaju na visoku temperaturu pa dolazi do pogoršavanja magnetnih karakteristika magnetnog jezgra rotora. Umesto ovog sistema rada treba koristiti hemijsku supstancu, tečni rastvor u koji se potopi rotor i posle određenog vremena veoma lako se čiste žlebovi rotora.
Figure 9. … sometimes it has to be well heated and burned in order to get the wire out of the rotor grooves more easily…
Note: When heating with a flame, the rotor core, which is made of laminated magnetic sheets that are used to make the rotor core, is heated to a high temperature, causing the magnetic characteristics of the rotor magnetic core to deteriorate. Instead of this work system, a chemical substance should be used, a liquid solution in which the rotor is immersed and after a certain time, the grooves of the rotor are very easily cleaned.
Slika 10. Čišćenje ostataka laka i izolacije iz žlebova rotora
Figure 10. Cleaning the remains of varnish and insulation from the grooves of the rotor
Slika 11. Posle čišćenja, ponovno vraćanje i pozicioniranje kolektora na svoje mesto.
Figure 11. After cleaning, returning and positioning the collector in its place.
Slika 12. Posle detaljnog čišćenja, rotori su spremni za ulaganje izolacije u žlebove
Figure 12. After thorough cleaning, the rotors are ready to insert the insulation into the grooves
Slika 13. Izolacija je postavljena u žlebove. Sve je spremno za ubacivanje novog namotaja u žlebove rotora
Figure 13. The insulation is placed in the grooves. Everything is ready to insert the new winding into the grooves of the rotor
Slika. 14. Kako kaže majstor vikler: „Najlakši deo posla“.
Figure. 14. As the master winder says: “The easiest part of the job.”
Slika 15. Još malo pa gotovo.
Figure 15. Just a little more and it’s over.
Slika 16. Namotani rotori. Kako kaže majstor, pola posla.
Figure 16. Coiled rotors. As the master says, half the job.
Slika 17. „Presovanje“ žice tj. krajeva sekcija namotaja u kanalčiće glava  kolektorskih lamela.
Figure 17. “Pressing” the wire, i.e. the ends of the winding sections into the channels of the heads of the collector lamellas.
Slika 18. „Zatvoreni“ kanalčići na lamelama kolektora.
Figure 18. “Closed” channels on collector lamellas.
Slika 19. Sečenje viška žice …
Figure 19. Cutting excess wire …
Slika 20. … Spremno za punktovane ili za lemljenje krajeva namotaja na kolektorske lamele…
Figure 20. … Ready to be punched or soldered to the ends of the coils on the collector segments…
Slika 21. … Najosetljiviji deo posla. Punktovanje kolektora. Umesto punktovanja može se koristiti i lemljenje.
Figure 21. … The most sensitive part of the job. Punctuation of the collector. Soldering can be used instead of dotting.
Slika 22. Kolektor rotora sa završenim punktovanjem…
Figure 22. Rotor collector with completed puncturing…
Slika 23. Posle punktovanja ili lemljenja krajeva namotaja na kolektorske lamele vrši se obavezna provera kontakata žice sa lamelom kolektora. Omski test.
Figure 23. After puncting or soldering the winding ends to the collector lamellas, a mandatory check of the wire contacts with the collector lamella is performed. Ohm test.
Slika 24. S obzirom da su ovo rotori za pikamere, mašine koje rade u teškim uslovima, postavlja se mehanička zaštita od kamenčića i komadića betona kako prikazuje slika…
Figure 24. Since these are picameter rotors, machines that work in harsh conditions, mechanical protection against stones and concrete chips is installed as shown in the picture…
Slika 25. … Ova zaštita pruža mogućnost da rotor „preživi“ udarce sitnih komadića koje usisa ventilator. Sada je rotor spreman za zatvaranje žlebova izolacionim klinovima koji su kod ovakvih rotora, obično od prešpan papira.
Figure 25. … This protection provides the possibility for the rotor to “survive” the impact of small pieces sucked in by the fan. Now the rotor is ready to close the grooves with the insulating wedges that are in such rotors, usually made of laminated paper.
Slika 26. Rotori su potpuno završeni i spremni za lakiranje…
Figure 26. The rotors are completely finished and ready for varnishing …
Slika 27. … Ali, pre lakiranja rotor mora biti izbalansiran na mašini za balansiranje. Majstori kažu: „Mora biti doveden u balans“, Prvo balans ispitivanje…
Figure 27. … But, before varnishin, the rotor must be balanced on a balancing machine. The masters say: “It must be brought into balance”, The first balance test…
Slika 28. Početak balansiranja rotora pre lakiranja postupkom dodavanja mase u odgovarajući žleb. Velika greška u balansu, što pokazuju instrumenti na mašini! Kasnije ćemo videti drugi, krajnji test balansa rotora.
Figure 28. Beginning of balancing the rotor before varnishing by adding mass to the appropriate slot. A big mistake in the balance, as shown by the instruments on the machine! Later we will see the second, ultimate rotor balance test.
Slika. 29. Grejanje rotora pre lakiranja na temperaturi od  60 C, najmanje 20 minuta. Zagrevanje rotora omogućava bolje prodiranje laka u namotaje rotora.
Figure 29. Heating the rotor before varnishing at a temperature of 60 C, for at least 20 minutes. Heating the rotor allows better penetration of the varnish into the rotor windings.
Slika 30. Lakiranje i pečenje rotora na 100 C, 30 minuta.
Figure 30. Varnishing and baking the rotor at 100 C, 30 minutes.
Slika 32. Posle lakiranja kolektor se obrađuje na strugu gde se čisti lak sa tela rotora.
Figure 32. After varnishing, the collector is machined on a lathe, where the varnish is cleaned from the rotor body.
Slika 33. Čišćenje ostataka opiljaka bakra iz međulamelne kanalske izolacije kolektora motora
Figure 33. Cleaning the remains of copper filings from the interlamella channel insulation of the motor collector
Slika 34. Obavezna provera, ima li spoja između dve lamele. Magnetni test.
Figure 34. Mandatory check, whether there is a connection between two slats. Magnetic test.
Slika 35. Rotori su spremni za novo balansiranje.
Figure 35. The rotors are ready for new balancing.
Slika 36. Početak balansiranja… Očitavanje greške..
Figure 36. Start of balancing… Error reading..
Slika 37. Na kraju. Izbalansiran rotor. Odlična vrednost, ispod 5.
Figure 37. Finally. Balanced rotor. Excellent value, under 5.
Slika 38. Rotori su izbalansirani metodom dodavanja mase. Koristi se dvokomponentna balans masa A i B plava i žuta.
Figure 38. Rotors are balanced using the mass addition method. A two-component mass balance A and B blue and yellow is used.
Slika 39. Sušenje balans mase rotora posle nanošenja mase, 30 minuta. Pojačana čvrstoća posle pečenja.
Figure 39. Drying of the balance mass of the rotor after mass application, 30 minutes. Increased strength after baking.
Slika 40. Na kraju, gotovi rotori spremi za montažu i sklapanje motora i ugradnju u mašinu ili uređaj koji pokreću.
Figure 40. Finally, the finished rotors are ready for assembly and assembly of the motor and installation in the machine or device they drive.

And, let’s conclude with one important piece of advice

Replacing the ball bearings on the electric motor is very important and important for proper operation. Bearings are the only part of the electric motor that are expendable and have a shelf life.

If they are not replaced on time, the motor may not work properly, and in the last case, they may fall apart and mechanically damage the coils.

It is also necessary to replace the brushes and their holders if any damage is observed.

No references, because is original work.