Electrical generator or motor structure – Dynamoelectric – Linear
Reexamination Certificate
2000-05-04
2001-10-02
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Linear
Reexamination Certificate
active
06297570
ABSTRACT:
BACKGROUND INFORMATION
Primary parts of linear motors have an array of motor windings which receive electric power from the outside through a feeder cable. There are generally two options for connecting the feeder cables. First, the feeder cable can be connected to the motor windings directly in the interior of the motor; this has the advantage of a very space-saving design. Second, it is conventional in general today to cast the primary parts of linear motors with a casting compound that is cured and provides insulation to prevent leakage currents and relative movements of the motor windings with respect to one another. However, this has the disadvantage that after the casting compound has cured, the terminals of the feeder cable are also cast in the compound and thus are no longer accessible. Thus, the entire primary part is rendered useless if there is damage to the cable, which can occur especially easily if the primary part is used as a moving part.
This can be avoided by mounting a terminal box. The terminal box is an additional terminal housing mounted on the housing or the like outside the primary part and inserted into the motor windings leading out of the primary part and secured on a terminal strip. The actual lead wire is also inserted into the terminal box and connected to the conductors of the motor windings by the terminal strip. This has the advantage that the feeder cable can be replaced easily in the event of damage and the primary part can be used further. On the other hand, this requires more space, additional components and additional assembly steps.
SUMMARY
An object of the present invention is to provide a primary part for a linear motor where the feeder cable is replaceable, has a relatively compact design and can be manufactured easily.
According to the present invention, the terminal elements for the feeder cables are embedded in the casting compound, where the contact parts for assembly of the feeder cables are exposed to the outside. Since the casting compound hardens after being cast, the terminal elements are securely held by the casting compound and are insulated from one another due to the electrical properties of the casting compound. Thus, it is not necessary to place a separate terminal box on the motor.
The electrically conducting terminal elements and/or their contact parts may be designed to advantage as a threaded rod, a bushing with an inside thread, a plug, a socket or the like.
Multiple terminal elements are provided to advantage, with adjacent elements being separated by projecting webs of casting compound. To further improve the mechanical and/or electric properties of the webs, a suitable reinforcing material may be embedded in the material of the webs.
The housing of the primary part may advantageously contain a terminal compartment having walls at least partially defined by the casting compound, with the terminal elements opening into this compartment and/or extending there. Such a terminal compartment can be covered advantageously with a cover which can be bolted to the housing. The feeder cable then advantageously passes through the cover and is secured on the cover as a cable grip.
In a method of manufacturing the primary part according to the present invention, the required motor windings are prepared and introduced into a housing. A die having a shape complementary to that of the terminal area to be created is secured on the housing, where the terminal elements are in turn secured on the die at suitable locations. Then the housing and the die are cast with the casting compound, and if needed, reinforcing material can be attached to the die prior to casting. After the casting compound has hardened, the die can be removed, so the terminal elements are accessible for connecting the feeder cables.
REFERENCES:
patent: 4626721 (1986-12-01), Ouchi
patent: 5625244 (1997-04-01), Bradfield
Jones Judson H.
Ramirez Nestor
Siemens Aktiengesellschaft
Staas & Halsey , LLP
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