Sine Wave Filters introduction
Sine wave filters (also known as sinusoidal filters) are passive components used to provide electrical circuits with the correct frequencies to ensure optimal performance. They are low pass devices which means they let low-frequency signals pass but block or impede high frequency signals. Circuits requiring longer cables usually have sinusoidal filters to convert rectangular pulse width modulation (PWM) signals into smooth wave voltage. This will prevent premature circuit damage and prolong the lifespan of AC motor drives by reducing stress on the motor’s insulation.
What are sinusoidal filters used for
Sinusoidal filters protect motor windings and bearings from damage due to voltage spikes, cable stripping, current loss and overheating. These filters are used in equipment such as pumps, ventilators, conveyors, compressors, elevators and cranes.
Inomax Sine Wave Filters
Inomax Sine Wave Filters provide a cleaner, sinusoidal power supply to your motor. This reduces heat buildup, extends cable range, and minimizes noise. Enjoy improved motor health, system performance, and meet stricter EMI regulations with a Inomax filter. Inomax Sine Wave Filters are ideal for applications requiring sinusoidal output waveforms. They can handle a wide range of frequencies, from the standard 50 Hz/100 Hz/200 Hz all the way up to 1,600 Hz. This is achieved through the use of carefully designed capacitor modules and cable sets. Our filters are built to handle a rated voltage of 220V 400V 440V 480V 525V 690V AC and are available in current ratings from 1.3A to 710A, making them suitable for various applications.
Current and voltage rating
Inomax’s standard sine wave filters are designed to be applied with most commonly used standard motor drives and motors available on the global market. For dedicated and special requirements Inomax does design customized sine wave filters adapted to the specific eeds. In principle the nominal motor current and the duty cycle is defining the
size of the output filter. Inomax sine weave filters are rated for 150% overload for 1 minute, ones per hour. Above 150% rated current the saturation of the inductance can be reached and destroy the apacitors.
It is recommended that the rated current of the sine wave filter shall be equal to or greater than the nominal motor current and should correspond and be compatible with the ratings and duty cycle capability of the motor drive.
For motor drives feeding isolation transformers select a sine wave filter with a current rating equal or greater than that of the transformer primary current.
Sine wave filter selection
With regard to the voltage, Inomax offers sine wave filter for 400 VAC, 500 VAC, 600 VAC and 690 VAC applications. Even for short cable installations, at voltages > 500 VAC sine wave filter are recommended, to protect the motor winding insulation against high voltage peaks.
In cases the motor drive selection has been made prior to the sine wave filter selection, the usual way is to size the sine wave filter to the orresponding motor drive. Nevertheless, the proper power selection depends on one side upon the drives related specifications, e.g. rated current, voltage, line frequency, motor drives switching frequency, motor frequency, the ambient conditions (temperature, altitude) and on the other side on the motor and application performance requirements. In addition the motor cable length, cable type, motor type, and some particular application requirements needs to be considered.
