Rectifier Assemblies

Built using combinations of power thyristors and diodes mounted into heatsinks and connected as single or three phase bridges, inverse parallel circuits. Other arrangements to customer specification are available. Units can be supplied with semiconductor protection fuses, and overvoltage and dv/dt protection. Cooling can be air, natural convection or fan-assisted, water-cooled or oil-immersed. As system current increases it is more likely that fan-assisted air or water-cooling will be required. PPI have previously supplied three-phase diode bridges for >2500A in air convection conditions. Standard Designs: Single-phase bridge, diode, DC output 5-250A, 600 to 1600Vrrm. Single-phase bridge, thyristor, DC output 30-600A, 600 to 1600Vdrm. Three-phase bridge, diode, DC output 5-300A, 600 to 1600Vrrm. Three-phase bridge, thyristor, DC output 50-850A, 600 to 1600Vdrm. Single-phase inverse parallel thyristor (ac control), 25 –600A rms Three-phase inverse parallel thyristor (ac control), 20-1800A rms Resistance welding switches to 3200A Designs to Customer Specification: Much of our business is custom design. We are always willing to quote special circuits across a wide range of current and voltage, steady-state or overload rated, in individual or multiple quantities. Diode rectification to 10kA. Thyristor controlled rectification to 5kA. Examples of special custom designs: 1. 25kV 600A peak capacitor discharge circuit with fibre-optic thyristor control 2. Seven-way inverse parallel bridge assembly 30A 3. 2500A water-cooled thyristor assembly for induction-heating control 4. IP66 rated thyristor controller 250A rms 5. Thyristor reversing bridges 2000A. Plate Rectifiers: Low cost single and three-phase bridges using parallel auto-diodes mounted into 3mm aluminium plates rated to 700A for welding and battery charger applications. Other circuits available on request. IGBT and MOSFET Assemblies: Designed to customer specification complete with gate-distribution pc boards, snubbers and drivers if required. Examples: 1. 1000A 150V oil-immersed MOSFET reversing H-bridge 2. 10kVA 80kHz pwm 350V three-phase MOSFET inverter 3. 120kVA 600V three-phase IGBT inverter. We can quote your requirements either from detailed specifications or basic operating parameters. Typical Applications for PPI Assemblies Traction rectifiers, vehicle and track-side supplies DC motor drives AC motor soft-starts Industrial Battery chargers, Plating rectifiers Cathodic Protection, Welders Electrostatic Precipitators, Laser supplies, Temperature Controllers Heat treatment systems, Magnet supplies

For more information on Rectifier Assemblies talk to Power Products International Ltd