DE2131528A1 - Method for isolating a commutator shrink ring - Google Patents

Description

Brown corporation, Boveri β Cie., Baden (Switzerland)

Procedure for Isolieruni? a commutator shrink ring

The present invention relates to a method for Isolation of a commutator shrink ring.

Shrink rings for shrink ring commutators must be from Shrunk clay lamellar bandage can be isolated. The insulation must be dimensioned in such a way that it meets the eieivtrisehen occurring in operation and during the examination and mechanical stress is sufficient.

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209851/0579

It is known, for example, to provide ring-shaped, laterally open channels made of paper or mica as insulation use. This solution has the disadvantage that, for manufacturing reasons, such channels are relatively must have a large wall thickness and also hawser Have manufacturing tolerances. That's why either the mechanical preload generated by the Schrumofrinpr insufficient or undefined, or an auxiliary shrink ring must be used to counteract this deficiency compensates. The last-mentioned method is particularly useful for shrink rings inserted into the side of the slats expensive and takes up a lot of space, which leads to high and heavy slats.

Another known solution is to replace the shrink ring on its contact surface by a thin, pressure-resistant and dimensionally accurate insulation layer to isolfe ren and on the other sides the distances between the shrink ring and Live parts should be selected so large that no flashover occurs either during operation or during the voltage test can occur. A large distance from the live parts must be selected, especially in the axial direction because of the floating discharges that occur Flashover over the shrink ring insulation already occurs at lower voltages than a flashover over

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the same distance. This results in this Solution to the disadvantage that the lever arm of the force exerts the screw ring on the lower larvae flap, gets bigger. This increases the bending resistance and consequently the stress on the lamella. The lamella must be higher so that no plastic deformation occurs be rooted, i.e. the commutator becomes heavier and more expensive.

The purpose of the invention is to create a method that the aforementioned Kachteile of the previous Avoids constructions.

The inventive method is characterized in that the shrink ring before shrinking on the Commutator completely covered with an insulating film.

It is useful if you use the shrink ring wrapped in a tape-shaped insulating film.

It can be beneficial when using higher voltages be when the shrink ring is enveloped with an insulating film consisting of at least two layers, with the layer facing the shrink ring is made of mica or mica-containing paper. To a

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Damage to mica or mica paper existing layer when applying the insulating film Avoid, it can be useful if you get one off Three layers of insulating foil are used, the one consisting of mica or mica-containing paper Layer is provided on both sides with a layer of insulating material, e.g. Polyimld.

The invention is explained in more detail below with reference to the drawing. Show it:

Figure 1 shows a first example of the application form

method according to the invention; and Figure 2 shows a second example of the application form process according to the invention.

To isolate the commutator shrink ring a 1 from the commutator 2, the former is wrapped in overlapping layers, for example two layers, with an insulating tape J> consisting of an electrically, mechanically and thermally high-strength polyimide film, before being shrunk on, then heated to the temperature required for shrinking and then shrunk on, without destroying the insulation.

In this way, the one that is shrunk onto the commutator 2 Komrniitat-orsohEumpfring 1, as can be seen from Figure 1,

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completely surrounded by an insulation layer 3, the latter advantageously having a maximum thickness of about 0.5 mm, so it is practically not is compressible and therefore does not represent an uncertainty factor when determining the amount of shrinkage. The distances between the shrink ring 1 and the live parts 2 can be chosen very small, so that the through the stress caused by the shrinkage K in the cross-section X-X can be kept as low as possible, since the shrink ring 1 does not have to be arranged relatively far away from the groove base 5, as was previously the case, because of the risk of rollover.

In order to achieve even greater electrical safety when higher operating voltages are used, as can be seen from FIG wherein the shrink against the ring 1 to directional layer

* ns mechanically stronger, electrically insulating plastic material, such as polyimide film or insulating paper and the other made of mica or mica-containing paper θ.

one coated with a cash weldability under pressure and heat fluorocarbon resin polyamide

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tape is used, whose fluorocarbon synthetic resin layer is directed against the shrink ring 1, then takes place when the shrink ring I is heated the insulating tape 3 is glued to the shrinking temperature so that it adheres well to the shrink ring 1,

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Claims (10)

- ^γ "213 V PATENTA NSPRUEC HE (1) method for isolating an eommutator shrink ring, characterized in that the shrink ring is completely before shrinking onto the commutator covered with an insulating film 2. The method according to claim 1, de, characterized in that the shrink ring is wrapped with a tape-shaped insulating film 3 · The method according to claim 1, characterized in that the shrink ring with such an insulating film enveloped when the shrink ring is heated glued to the shrink ring at the shrinking temperature. 4. The method according to claim 3 »characterized in that that the shrink ring is covered with a fluorocarbon synthetic resin layer that can be welded under pressure and heat coated insulating film so that the fluorocarbon synthetic resin layer against the Shrink ring is directed too. 5. The method according to one or more of the preceding Claims, characterized in that an insulating film made of polyimide is used. 6. The method according to claim 1 or 2, characterized in that the shrink ring with one of at least 209851/0579 73/71 two layers of insulating film, with the layer facing the shrink ring being made of Mica or mica-containing paper 7 · The method according to claim 6, characterized in that the shrink ring with one of three layers existing insulating film, the inner layer consists of mica or mica-containing paper. 8. The method according to claim 6, characterized in that that ma.n an insulating film consisting of two layers is used, with one layer made of mica or mica paper and the other layer is made of polyimide 9 · The method according to claim 7, characterized in that an insulating film consisting of three layers used, the inner layer of mica or mica-containing paper and the two outer Layers made of polyimide 10. The method according to claim 1, characterized in that between the shrink ring covered with insulating film and the shrink surface of the commutator an additional insulating film consisting of two layers arranged one above the other is arranged, the against the shrink ring to directed layer of electrically insulating plastic ITateriaJL and the others made of mica or mica-containing paper. 209851/0579 Public Company BROWN, BOVERl & CIE. BATH ORIGINAL