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In the ___________ type of mounting the SCR is pressed between two heat sinks.
Bolt-down mounting
Stud-mounting
Press-pak mounting
Cross-fit mounting
Press-pak mounting
Press-pak mounting, also known as hockey-puck mounting, involves sandwiching the SCR between two high-thermal-conductivity heat sinks. This design provides double-sided cooling, significantly increasing the power handling capacity of the semiconductor device.
Press-pak mounting, also known as hockey-puck mounting, involves sandwiching the SCR between two high-thermal-conductivity heat sinks. This design provides double-sided cooling, significantly increasing the power handling capacity of the semiconductor device.
R╬╕JAтАЛ=R╬╕JCтАЛ+R╬╕CSтАЛ+R╬╕SAтАЛ тАФ Total thermal resistance formula for heat dissipation
The SCR wafer is held under high pressure between two metallic heat sinks using a clamping mechanism. This structure minimizes the thermal resistance between the junction and the cooling medium from both sides. Proper contact pressure is essential to ensure low electrical resistance and efficient heat dissipation.
Press-pak mounting provides superior heat dissipation compared to stud-mounting due to dual-sided cooling.
The thermal expansion match between the silicon wafer and the mounting structure is critical in press-pak devices.
Used extensively in high-current industrial applications where efficiency and thermal stability are paramount.
Excellent double-sided cooling capability
High current rating capacity
Lower thermal resistance (R╬╕тАЛ)
Requires specialized, precise clamping hardware
More complex assembly compared to bolt-down types
Requires maintenance of constant contact pressure
High-voltage DC (HVDC) transmission
Large industrial motor drives
Traction power converters
| Feature | Stud-mounting | Press-pak |
|---|---|---|
Cooling Surface | Single side | Double side |
Stud-mounting (Option B) is commonly used for lower power SCRs where the stud acts as both a terminal and a heat sink connection.
Bolt-down mounting typically refers to devices with a flat base that is mechanically bolted to a heat sink, primarily single-sided.
C is correct тАФ Press-pak mounting uses two heat sinks to sandwich the SCR for efficient double-sided cooling.
Always relate thermal resistance to the physical contact area and pressure; higher clamping pressure in press-pak reduces thermal resistance, allowing higher junction current ratings.