Product Overview  |  Technical Specification  |  Applications  |  Case Study

Large and rapid variations in reactive power normally occur during spot welding operations and motor start-up. The Hybrid Filter minimizes the negative effects of these loads, resulting in improved power quality and system capacity. Spot Welding Spot Welding loads fluctuate extremely rapidly and consume large amounts of reactive power. Resultant voltage sags tend to reduce welding quality and can impact welding productivity. In addition, those loads often create a high level of voltage flickering, which frequently exceed the recommended IEEE limits. High-speed reactive compensation systems clearly offer the following benefits: Improve welding quality, increased process output and elimination of flickering. Significant capital investment is reduced by better utilization of the existing infrastructure.

The top and middle graphs demonstrate that the Hybrid Filter prevents voltage drop and flickering, substantially reduces the current and compensates reactive energy.   The bottom graphs demonstrate welder output current (Automobile industry). The optimal condition is a stable current within a range of 11,000 amp. With the Hybrid Filter, the current variations are +/- 200Amp and without the Hybrid Filter the current variations are +/- 800Amp. A stable current significantly improves welding quality. Over-current can cause damage to the electrodes as well as to the material being welded. Undercurrent during welding operations deteriorates welding quality.

Central Compensation of Start-Up Current of Large Motors

Large squirrel case inductive motors, when connected directly on-line, consume high current during the start-up period (six times higher than steady state operation). However, if the network is weak, the high current leads to substantial voltage drops which interfere with other loads, reducing the initial torque and increasing start-up time.

The Hybrid Filter tracks the reactive current, compensates it within one cycle, and provides the following features:

• Main protection against voltage drop cause by high momentary consumption of reactive current
   
• Central starting of all loads, thus avoiding the use of individual starters required to protect the mains against voltage drop
   
• Direct connection of motor to mains, to obtain maximum torque during connection. This feature is unique to the Hybrid Filter system, since starters of all types reduce the current going through the motor, thereby reducing the starting torque.

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