Yihai Kerry's oilseeds and grain business processes soybeans, rapeseed, peanuts, sunflower seeds, sesame seeds, cottonseeds and grains (wheat and rice) into edible oils, feedstuffs, rice noodles, cereals and soy milk powder.
In the production process, a large amount of electric energy is consumed, so the electricity cost has been high, and the power quality status is also understood by the management manufacturer or the power supply bureau, and there is no professional power quality analyzer tool to verify. The entire production process cannot grasp the power quality status, and it is impossible to find a suitable method to save power.
The most energy-consuming in the power supply and distribution system of the factory is the power transformer and distribution line. Due to changes in market demand and changes in factory production processes, the power transformer capacity according to the planned equipment is usually not matched with the actual load. For example, the transformer capacity is too large, the load rate is low, the transformer loss is large, and the distribution line thickness and length are small. Unreasonable and non-standard, it also causes a significant increase in line losses.
Based on the above test problems, the customer does not have the corresponding detection means, including the main concerns of power, harmonics, line loss, power factor and other functions.
The Fluke engineer personally carried the Fluke 435-II, a Fluke three-phase power quality analyzer, to the factory for on-site power monitoring. Fluke engineers replaced professional work clothes, wearing safety helmets, high-voltage arc-proof masks, 10000 V high-voltage insulated gloves and other equipment, and detailed testing of voltage, current, frequency, power, harmonics, and power factor that customers care about.
The field voltage is 380 V, the current is more than 2,000 amps; the distance between the high voltage busbars is very close, the current loop is more dangerous to intersperse, and the busbar is placed at the bottom of the cabinet at a depth of half a meter from the ground, which is very difficult to test (as shown below). After the test was completed, the Fluke 435-II generated a detailed power quality report, and the customer praised the function of our instrument.
According to Fluke's special report software, the voltage harmonic report is as follows: the total voltage distortion rate is 2.2%, which is 5% of the national standard, and the power factor is 0.97. This indicator is good, and the customer informs the power supply bureau that there will be targeted rewards. .
The figure below shows the current harmonic diagram, with 3 and 5 harmonics slightly exceeding the standard. Usually harmonics cause a large amount of electric energy to be wasted, resulting in large economic losses. This harmonic may be caused by a three-phase imbalance or by a non-linear load, which may cause some pollution to the power grid system.
harmonic
The main causes of harmonics are: Since the sinusoidal voltage is pressed against the nonlinear load, the fundamental current is distorted to generate harmonics. The main non-linear loads are UPS, switching power supply, rectifier, inverter, inverter and so on.
Harmonic current is the root cause of all harmonic problems, and harmonic voltage is also caused by harmonic current. Therefore, when studying the hazard caused by harmonics, it mainly refers to the hazard of harmonic current.
First: causing the cable to overheat
Harmonic current can cause the cable to overheat when it flows through the cable. The cause of this phenomenon is the skin effect of alternating current. The skin effect is a physical phenomenon in which the surface of the conductor is concentrated when an alternating current flows through the conductor. The higher the frequency of the current, the more concentrated the current is on the surface of the conductor. Due to the skin effect, when a higher frequency harmonic current flows through the conductor, the effective cross-sectional area of ​​the conductor is smaller than the actual cross-sectional area of ​​the conductor. A small cross-sectional area means greater resistance, which means more heat is generated. When a higher frequency harmonic current flows through the conductor, the conductor exhibits a greater resistance than the fundamental current, so a harmonic current of the same magnitude produces more heat than the fundamental current.
Second: causing the transformer to overheat
When the harmonic current flows through the transformer, it will cause additional heat to the transformer, causing the transformer to overheat when the rated power is not reached, resulting in a decrease in the actual capacity of the transformer.
Third: causing damage to the reactive power compensation device
The influence of harmonic current on the reactive power compensation device is also very common, which has become an unavoidable problem in the energy-saving technical transformation of enterprises. In the energy-saving retrofit, a large number of inverters are used, and the inverter generates severe harmonic currents.
The PA system of the audio generally refers to the audio audio sound reinforcement system. The audio system can be a system composed of an audio source, a preamplifier, a power amplifier, and a speaker. The sound source in the system is a microphone, which is used to convert the sound signal into an electrical signal. The sound source can also be other sound sources, such as tape players, CD players, MD players, etc.
If the sound source is not a microphone, you can cancel the front end.This system is the simplest system for conferences and requires a microphone. Since the output voltage signal of the microphone is very small, between O.lrnV and tens of millivolts, it is not enough to directly drive the power amplifier. The sensitivity of the power amplifier (rated input) is often specified around 0dB (0.775). The power amplifier transmits the amplified electric power signal to the speaker (usually called a speaker), and the speaker then converts the electric power signal into an acoustic signal and radiates it into the space to complete the sound amplification effect, that is, sound reinforcement.
Audio equipment probably includes amplifiers, peripheral equipment (including limiters, effects, equalizers, exciters, etc.), speakers (speakers, speakers), mixers, sound sources (such as microphones, musical instruments, VCDs, DVDs) display devices and so on. Among them, the speaker is the sound output equipment, speakers, subwoofers, etc., a speaker includes high, low, medium three kinds of speakers, three but not necessarily three
Our company's ABS Molded PA Speaker products not only have high quality and competitive prices, is a Chinese supplier trusted by buyers all over the world market, choose us and you have chosen a bright and brilliant future
Abs Molded Pa Speaker,Portable Pa System,Pa System,Portable Sound System
NINGBO LOUD&CLEAR ELECTRONICS CO.,LIMITED , https://www.loudclearaudio.com