What Equipment will Harmonics Cause Harm to?
With the continuous improvement of industrial automation, variable frequency air compressors have gradually become mainstream products on the market, and frequency converters have also been widely used.
With the continuous improvement of industrial automation, variable frequency air compressors have gradually become mainstream products on the market, and frequency converters have also been widely used. The frequency converter of the variable frequency air compressor adjusts the voltage and frequency of the output power supply by turning on and off the internal IGBT, and provides the required power supply voltage according to the actual needs of the motor, thereby achieving the purpose of energy saving and speed regulation.
However, we cannot ignore the harm caused by the large-scale application of frequency converters. For the motor field, the normal use of the frequency converter may cause damage to the motor to a certain extent and affect the normal operation. Let’s take a closer look at what equipment harmonics can cause harm to?
01 Transformer
Current harmonics will increase copper losses, and voltage harmonics will increase iron losses. The overall effect is to increase the temperature of the transformer, affect its insulation capabilities, and reduce the capacity margin. Harmonics may also cause resonance between the transformer windings and inter-line capacitance, and cause core magnetic flux saturation or distortion, thereby producing noise.
02 Electric Motor
The main impact of output harmonics on the motor is that it causes additional heating of the motor, resulting in additional temperature rise of the motor. The motor often needs to be derated. Due to the distortion of the output waveform, the repeated peak voltage of the motor is increased, affecting the insulation of the motor. Harmonics will also Causes motor torque pulsation and increased noise.
03 Switchgear
Due to the existence of harmonic currents, switching equipment produces a very high di/dt current change rate at the moment of starting, which increases the peak value of the transient recovery voltage and damages the insulation.
04 Power Capacitor Bank
Standard specifications for general capacitors stipulate that only 35% of the maximum current is allowed to be overloaded. However, in actual operation, severe overloading often occurs due to the influence of harmonics. Since the impedance of a capacitor decreases as the frequency increases, when harmonics are generated, the capacitor becomes a current sink point and a large amount of current flows into it, resulting in overheating, increased stress on the dielectric, and even damage to the power capacitor. When the capacitor and line impedance reach resonance conditions, vibration short circuit, overcurrent and noise will occur.
05 Measuring Instruments
For measuring instruments such as electric energy meters, harmonics will cause the induction turntable to generate additional electromagnetic torque, causing errors and reducing accuracy.
06 Protect electrical appliances
The current contains harmonics, which will generate additional torque, change the operating characteristics of the electrical appliance, and cause malfunction. Others such as lighting equipment, communication equipment, computer equipment, carrier frequency remote control equipment, etc. are all susceptible to harmonic interference, affecting their normal work or reducing their service life.
07 Power electronic equipment
In many situations, electronic equipment often generates harmonic current sources, and it is easy to experience harmonic distortion and malfunction.
