The present disclosure is directed to electrical systems, and more particularly to liquid cooled electrical systems.
Electrical systems, such as wound field generators, often generate waste heat during operation. If the waste heat is allowed to accumulate, electronics or electrical equipment within the electrical system can be damaged. Numerous cooling techniques have been used to address the waste heat. One effective cooling technique that has been used is liquid cooling.
A liquid cooled electrical system passes a non-conductive liquid coolant over the components within the electrical system, thereby absorbing heat from the components into the coolant. The coolant is then passed out of the electrical system and allowed to cool. Once cooled, the coolant is recycled through the electrical system.
While the non-conductive coolant does not short out the electrical components within the electrical system due to its non-conductive nature, friction between the coolant and the cooling passage walls generates a static charge within the coolant. The static charge is then deposited on the cooled electronic components as the coolant passes over them. If the energy differential between the statically charged electrical components and the electrical component's housing gets too high, a static discharge between the components and the housing occurs. The static discharge can cause electrical faults, and damage to the electrical components.
A liquid cooled electrical system includes at least one component, and a coolant passageway contacting the at least one component such that a liquid coolant cools the component. A coolant filter within the electrical system filters the coolant passageway upstream of the component, wherein the coolant filter comprises a semi-permeable filter material and a Static Dissipating Agent (SDA).
A coolant filter includes a filter material, an SDA contained within the filter material, and a frame supporting the filter material.
A method for preventing static discharge in an electrical system includes the steps of passing a liquid coolant through a coolant filter, dispersing an SDA within the coolant as the coolant is passed through the filter, and passing the coolant and SDA over a diode assembly which is an electrical component within the electrical system.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
Also illustrated in the generator 20 is a liquid coolant passageway 24. The liquid coolant passageway 24 receives coolant from a filtered coolant passageway 32 and outputs spent coolant to a spent coolant passageway 42. A filter 30 and pump 36 arrangement draws unfiltered coolant from a coolant reservoir 40 along a reservoir coolant passageway 44, while the spent coolant passageway 42 deposits spent coolant back in the reservoir 40 to be cooled. In an alternate configuration, the filter 30, pump 36, and the coolant reservoir 40 are contained within the housing 38.
As the coolant flows through the passageways 24, 32, 42, 44 a static charge is generated within the coolant due to friction between the coolant and the passageway walls. The static charge is deposited on the cooled components as the coolant runs over the components. The buildup of static charge on the electrical rotor 28 and rotating diode assembly 22, as well as on other electrical and mechanical components, such as bearings, can cause sudden electrical discharges between the components 22, 28 and the component housing 38. In order to prevent static buildup within the coolant, a static dissipating agent (SDA) is dispersed within the coolant. Once dispersed, the SDA compound can be in the form of a mixture with the coolant (as illustrated in the included drawings) or be dissolved into the coolant, depending on the particular SDA compound and coolant used within the electrical system. The SDA compound dissipates static buildup within the coolant flow, thereby preventing a static charge from being deposited on the cooled component 22, 28. The significantly lower static buildup on the cooled component 22, 28 prevents the energy differential between the component 22, 28 and the component housing 38 from building up, and thereby prevents static discharges between the component and the component housing 38.
In the illustrated example of
Once the filter element 130 is saturated with the SDA compound 220, the filter is installed in a cooling system such as the cooling system illustrated in
When the filter element 130 is saturated with the SDA compound 220 during the treatment, the filter 30 can continue dispersing the SDA compound 220 into the coolant for at least the lifespan of the filter 30. In this way, the coolant filter 30 is replaced due to routine maintenance before the suspended SDA compound 220 is exhausted, thereby ensuring that the filter 30 is always dispersing the SDA compound 220 within the coolant.
The above described system is illustrated in
Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. For that reason, the following claims should be studied to determine the true scope and content of this disclosure.