Counterweight Tensioning Assemblies provided by IMPulse are used to maintain constant tension on the catenary wires during all normal operating temperatures. As the catenary wires expand or contract with changes in temperature, the weight moves up or down thereby maintaining a constant tension.
IMPulse NC LLC Counterweight Tensioning devices have a three to one mechanical ratio. This ratio reduces the amount of weight required to maintain the tension. Thus, the tension applied to the catenary is three times the weight of the counterweight. The catenary wires are terminated to the counterweight tensioning device using a proportional yoke plate. The yoke plate provides tension at a two to one ratio where the messenger wire tension is twice that of the contact wire.
IMPulse provides many types of counterweight assembly options from solid body counterweights to plate style. The plate style of weight is cast in segments with an interlocking feature maintaining weight stack alignment. The plate style also offers the versatility of adjustment should system requirements change. IMPulse counterweights provide for alternate methods of mounting such as inside pole, within beam and outside the pole. A counterweight is commonly cast of lead segment(s). However, other materials such as concrete may be specified.
IMPulse incorporates be specified various safety features into counterweight design. Counterweight systems, due to their weight capabilities, incorporate both high and low temperature stops. Low temperature stops are required to prevent system damage when temperatures fall below freezing. This feature is furnished to prevent excessive sag in messenger wire during heavy icing conditions. IMPulse also provides optional mechanical brakes which stop the counterweight should system tensions reduce too quickly, which is the case during catenary wire breaks.