Rubycon Corporation Screw Terminal Capacitors

Screw terminal capacitors are used in high-power industrial applications requiring very large capacitance values and high ripple current capability. Common applications include large UPS systems, energy storage systems, heavy industrial motor drives, traction systems, and power quality equipment. The screw terminals allow secure high-current connections that can handle hundreds of amps. These capacitors are typically used in applications above 50kW where capacitance values of 10,000uF to 100,000uF or more are required. The large can sizes (up to 90mm diameter) provide excellent thermal performance for high ripple current applications.

Use screw terminal capacitors for high-power applications requiring capacitance above 10000uF and high ripple current.

Screw terminal capacitors are typically mounted using mounting clamps or brackets due to their large size and weight. The capacitors have a cylindrical aluminum can that is secured to a chassis or mounting plate using metal clamps. The clamp should provide even pressure around the can circumference without deforming the case. Some capacitors have threaded mounting studs on the bottom for direct attachment. The mounting must provide mechanical support for the weight (large capacitors can weigh several kilograms) and withstand vibration. Electrical connections are made using ring terminals and screws to the capacitor terminals. Proper torque must be applied to ensure good electrical contact without damaging the terminals.

Use appropriate mounting clamps and ensure proper torque on electrical connections.

LXS and LXM series differ primarily in temperature rating and lifetime. LXS series is rated for 85C with typical lifetime of 2,000-5,000 hours, making it suitable for applications with moderate operating temperatures. LXM series is rated for 105C with extended lifetime of 5,000-10,000 hours, providing higher reliability for demanding applications. LXM uses enhanced electrolyte formulation and improved construction techniques to achieve the higher temperature rating. Both series are available in similar capacitance and voltage ranges, though LXM may have slightly larger case sizes for equivalent ratings. For indoor applications with controlled temperatures, LXS offers cost-effective performance. For outdoor or high-temperature industrial environments, LXM is recommended.

Select LXS for cost-effective high capacitance; LXM for high-temperature applications.

Screw terminal capacitors can handle very high ripple currents due to their large size and excellent thermal performance. Ripple current ratings range from 10A to over 100A rms depending on capacitance, voltage rating, and case size. For example, a 100,000uF 400V capacitor in 76x143mm size might have 50-60A ripple current rating at 85C. The large aluminum can provides substantial heat sinking capability. At lower ambient temperatures, ripple current capability increases significantly. These capacitors are designed for applications with high ripple current such as large motor drives and UPS systems. For extremely high ripple current requirements, multiple capacitors can be connected in parallel.

Select larger case sizes for higher ripple current; parallel multiple units for very high currents.

Screw terminal capacitors incorporate several safety features. The pressure relief vent opens if internal pressure becomes excessive, preventing catastrophic rupture. This vent is typically located on the top of the capacitor and is designed to release pressure safely away from personnel. The aluminum case provides mechanical protection and heat dissipation. High-quality rubber seals prevent electrolyte leakage under normal operating conditions. The screw terminals are designed to maintain secure electrical connections even under vibration. Some large capacitors also include discharge resistors internally for safety. Always follow proper safety procedures when working with large capacitors due to the stored energy hazard.

Ensure pressure relief vent is unobstructed and follow safety procedures for high-energy capacitors.