Heat sink system and assembly

1. A heat sink system with reduced airborne debris clogging, for cooling power electronics, the heat sink system comprising:

a heat sink having a plurality of fins;

a housing configured to direct air flow around the side of the heat sink and then through the fins of the heat sink at a back of the heat sink;

an inlet airway passage formed between a wall of the housing and said side of the finned heat sink to allow air to pass within the housing, wherein said side of the heat sink comprises at least one of said plurality of fins disposed directly in contact with the inlet airway passage; and

a transition seal between the heat sink and the inlet airway passage, said transition seal including a sloped portion having a radius of curvature and a slot proximate the inlet airway passage;

said plurality of fins include an outer fin at an outer end of the heat sink, said outer fin having a radius of curvature to match the radius of curvature of the sloped portion and having a thickness to fit into the slot.

2. The heat sink system according to claim 1 , wherein the outer fin of the heat sink is of a thickness to contact an inner edge of the slot.

3. The heat sink system according to claim 1 , wherein at least one fin of the plurality of fins is in thermal connection with the inlet airway passage.

4. The heat sink system according to claim 1 , wherein said plurality of fins include outer fins at opposing outer ends of the heat sink, with interior fins between the outer fins; and wherein the thickness of the outer fins is greater than a thickness of the interior fins.

5. In a cooling system for cooling power electronics where the cooling system includes a heat sink system that has air passing therethrough an inlet airway passage to reach a plurality of fins on a heat sink where reducing airborne debris clogging of the plurality of fins is preferred, the heat sink system comprising:

a transition seal between the heat sink and the inlet airway passage; and

a slot proximate the inlet airway passage to receive an outer fin of the heat sink;

a restriction element attached to a housing of the heat sink to define a pressure drop through the heat sink due to increased spacing between the plurality of fins;

wherein the outer fin is of a thickness to contact the inner edges of the slot; and

wherein at least one fin of the plurality of fins is in thermal connection with the inlet airway passage;

said transition seal being aligned substantially parallel with the heat sink and the inlet airway passage.

6. The heat sink assembly according to claim 5 , further comprising a sealing member within the slot.

7. The heat sink assembly according to claim 5 , wherein spacing between the plurality of fins is varied between fins.