## ST1200C..KP Series: Phase Control Thyristor The **ST1200C..KP** series represents a line of high-power, capsule-type (hockey puck) **Phase Control Thyristors** (SCRs) manufactured by Vishay (formerly International Rectifier). These components are designed for high-demand industrial power conversion and switching applications. --- ### 1. Key Technical Specifications The ".." in the part number represents the voltage code (e.g., ST1200C16KP indicates a 1600V rating). | Parameter | Typical Value | Description | | :--- | :--- | :--- | | **$I_{T(AV)}$** | 1200 A | Maximum average on-state current | | **$V_{DRM} / V_{RRM}$** | 400V to 2000V | Peak repetitive off-state and reverse voltage | | **$I_{TSM}$** | ~25,000 A | Maximum non-repetitive surge current (50Hz) | | **$V_{TM}$** | ~1.65 V | Maximum peak on-state voltage drop | | **$I_{GT}$** | 200 mA | Maximum DC gate current required to trigger | | **Package** | A-24 (K-Puk) | Press-pack ceramic capsule | --- ### 2. Physical Design: The "Hockey Puck" The **KP** designation refers to the physical package style. * **Double-Side Cooling:** The device is designed to be sandwiched between two heat sinks. This allows heat to dissipate from both the anode and cathode sides, maximizing current density. * **Pressure Mounting:** These do not have bolt holes. They require a specific mounting force (clamping) to ensure electrical contact and thermal conductivity. * **Ceramic Housing:** Provides high insulation and hermetic sealing for harsh industrial environments. --- ### 3. Electronic Functional Features 1. **Phase Control:** Unlike fast-switching thyristors, these are optimized for standard line frequencies (50Hz to 60Hz). They are "turned on" by a gate pulse and "turned off" when the current naturally drops to zero (natural commutation). 2. **High Surge Capability:** Designed to withstand massive current spikes without failure, which is critical for motor starting or short-circuit protection. 3. **Low Conduction Losses:** Optimized for low forward voltage drop ($V_{TM}$) to reduce power waste during the "on" state. --- ### 4. Common Applications Due to their massive current handling, they are used in: * **Large DC Motor Drives:** Speed control for industrial mills and cranes. * **Induction Heating:** Power supplies for metal melting. * **High-Voltage DC (HVDC) Transmission:** Power grid management. * **Electrochemical Processes:** High-power rectifiers for electrolysis or plating. --- ### 5. Identification Example `ST1200C18KP0` * **ST:** Standard Thyristor * **1200:** Current Rating ($I_{T(AV)}$) * **C:** Ceramic Capsule * **18:** Voltage rating ($18 \times 100 = 1800V$) * **KP:** Package Type (K-Puk)