The new MTE RLW series DIN-rail mounting, line reactors provide useful functions in addition to harmonics mitigation on the line side of variable speed drives. The properly selected RLW impedance line reactor in the input circuit virtually eliminates nuisance tripping of drives due to voltage spikes originating from switching sequences including power company VAR compensators. The MTE RLW Line reactors can also protect against short duration line sags. In addition the line reactors can also be used on the motor side of variable speed drives provided that an 80% loading factor is applied (i.e. : for example; for 80 amps motor current a 100 amp reactor is selected).
Obviously use on the output side of a variable speed drive leads to lower motor temperature, compensation for long motor cable capacitance, dv/dt reduction, peak voltage (PWM pulses) reduction, smoother running, less audible noise, less interference to adjacent systems, surge current protection for VSD output as well as improving motor performance and system efficiency.
RLW Line reactors from Westek Electronics are rated in percent impedance to retain some conformity with the ratings of conventional drive isolation transformers. There is a range of impedances to and current ranges to chose from, and in combination with line impedance, MTE RWL reactors can reduce harmonics to under 30% THID from values in excess of 100%.
Together with transformer and line impedance, they mitigate harmonic currents very effectively.
The impedance rating of a conventional isolation transformer can be determined by the following procedure: short circuiting the secondary winding, increase the primary voltage while monitoring secondary current and measure the primary voltage that causes rated secondary current to flow. Compare this value with the rated primary voltage to obtain a ratio equal to the transformer impedance rating.
- The RLW offers significant reductions in size, weight and cost while providing a high level of drive protection. The RLW reactor is designed for adaptability and installation ease for OEM’s, integrators and panel builders.
- The range of RLW reactors covers 415 volts, 3-phase and 690 volts, 3-phase. The former voltage rating comprises of motor ratings to 375 kW (full load current to 727 amps), and the latter, motor ratings to 750 kW (full load current of 540 amps). Impedance levels can be selected in3, 4 and 5% values.
- Their smaller size with reduced weight over the standard reactors provides great benefits to systems integrators as well as to installations requiring retrofitting.
- MTE RLW line reactors are manufactured to the exacting standards and are UL recognized and CSA certified.