1 Cleaning with the cleaning plate When the armature winding is burnt due to a short circuit fault, the fault point can usually be found by the observation method. In order to determine whether a short-circuit fault occurs inside the winding or between the commutator segments, the winding wire ends connected to the commutator segments should be disengaged, and then the check lamps should be used to check whether the commutator segments are short-circuited, such as on the commutator segment surface. If a short circuit or spark burns is found, usually use the grooved sheet shown in Figure 2 27 to scrape off the short-circuited metal chips, brush powder, corrosive substances, etc. until the test light is used to test that there is no short circuit. Mica powder and shellac or mica powder, epoxy resin and polyamide resin (650) are mixed into a paste, and then filled in a groove to make it harden and dry.
2 Clean the V-groove and V-ring of the commutator group. If the external inter-chip debris is carefully removed, the inter-chip short circuit cannot be eliminated. At this time, the commutator has to be taken apart, and the V-shaped groove and the V-shaped ring of the commutator group are carefully cleaned. Before disassembling the commutator, a 0.5~1 mm thick piece of elastic paper should be wrapped around the commutator for gasket insulation, and the fault should be marked, and then the stacking die should be placed. Take the commutator apart. Further check the faults between the commutator segments, the V-groove surface and the V-ring, and process them separately according to different faults.
3 If the inter-chip mica sheet is not replaced by the above method, only the inter-chip mica sheet can be replaced. The method of replacing the inter-chip mica sheet is as follows.
Place the above-mentioned disassembled commutator set on the flat plate, mark the faulty reversing piece, and then tighten it with a rubber ring, then remove the wire hoop or the weftless glass wire and grind it into a front end. A section of the wide saw blade is inserted between the faulty pieces, and after being loosened, the defective commutator piece is pulled out, and a new commutator piece of the same specification as the faulty commutator piece is inserted.
After the commutator segments are replaced, the commutator segments are tightened with iron hoops (inner cardboard). Heat the commutator set to 165 ° C ± 5 ° C, tighten the screw for the first tightening, after cooling, check the inter-chip short-circuit fault with the check lamp. If it is not eliminated, you should carefully look for the cause of the fault or repeat the above work; if the short circuit between the sheets has been eliminated, assemble it.