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Circuits and Circuit Laws
Published in Richard Cadena, Electricity for the Entertainment Electrician & Technician, 2021
If the voltage drop is excessive, then some equipment might not work properly or at all. Many switch-mode power supplies, like those found in computers, consoles, video projectors, digital amplifiers, and so on have an acceptable range of voltage input—typically from about 90 V to 250 V—and excessive voltage drop could cause the applied voltage at the load to drop below the minimum. Another problem with excessive voltage drop is that it is caused by high resistance and/or high current, either of which cause an increase in the heating of the conductors, and that could lead to significant deterioration of the insulation around the conductor, melted connectors, or worse. Excessive voltage drop is a symptom of a problem, which is that too much current is running through a conductor, or that the cross-sectional area of the conductor is too small for the amount of current that it is carrying.
Materials and their applications in the electrical industry
Published in David W. Tyler, Electrical Power Technology, 2016
Since all conductors in normal service have resistance, the passage of current along the conductor gives rise to a voltage drop. The voltage drop is in phase with the current producing it so that the power loss is equal to the product of voltage drop and current flowing. Consideronecore:Voltdrop=IRwhereR=resistanceofonecorePowerloss=voltdrop×current=IR×I=I2Rwattspercore
Electrical Planning
Published in Jason E. Weber, The Lighting Supervisor’s Toolkit, 2020
Length is also a factor for portable cable ampacity. As a cable's length is increased, the resistance of its' copper conductors increase as well. Increased resistance will cause the voltage of the cable to drop and generates heat. With an incandescent load, voltage drop causes the fixture to appear dimmer. With electronic loads such as LEDs or moving lights, voltage drop can cause the electronics to shut down or fail. To protect against these situations, derate the cable's ampacity as its' length increases. The second chart shown in Figure 7.6 provides recommended ampacity limits for “SOOW” cable. These reduced limits ensure that the voltage does not drop by more than 5 volts even if the load reaches 150% of the rated value.
Probe card-Type multizone electrostatic chuck inspection system
Published in Automatika, 2023
Yoon Sung Koo, Jae Hwan Kim, Chan Su Han, Sang Jeen Hong
The heating mechanism of the heating electrode of an ESC follows Joule’s law, which states that heat is generated when current is supplied to a metal body. Therefore, to heat a wafer, an electric current is supplied to the heating electrode in an ESC. However, when this current is delivered to the wafer, it can act as noise in the process plasma. Additionally, a high thermal conductivity material is required to uniformly heat the entire area of a wafer. Therefore, aluminum nitride and alumina were used as heating electrodes owing to their excellent electrical resistance and thermal conductivity [16]. The metal resistance of the heating electrode of an ESC follows the following relationship: R = ρL/A, where ρ is the resistivity of the metal, L is the length of the metal line between two terminals, and A is the area. The resistance in the electric circuit prevents the flow of current and causes a voltage drop. The resistance between two points in the circuit can be expressed as a ratio of the voltage and current [17], and depending on its value, it is classified into low, medium, and high resistance. As summarized in Table 1, circuits can be measured precisely based on the resistance value. The resistance measurement range of an ESC heating electrode corresponds to the megaohm range, i.e. high resistance [18]. In this study, a DMM (HIOKI’s DT-4282) with a built-in Megger circuit was used to accurately measure the resistance in megaohm using a 9.6 nA current source and internal reference resistance.
Design of decision-making support system in power grid dispatch control based on the forecasting of energy consumption
Published in Cogent Engineering, 2022
Natalya Kalantayevskaya, Kairat Koshekov, Sergey Latypov, Alexey Savostin, Kunelbayev Murat
This transformer plant has the capacity of 2х400 kVA: one transformer is working, and the other is a standby transformer. The transformer plant is powered from two mutually redundant sources DS 110/10 kV No. 7 and No. 11. The permanent supply is obtained from DS 110/10 kV No. 7. The energy consumption analysis for TS 10/0,4 кW №304 has demonstrated that the power output within [260 370] kW is optimal energy consumption during the summer period. According to the suggested algorithm with forecasted energy consumption above 380 kW, there is a need for putting into operation of the standby transformer. For the period when the power is more than 450 kW, it is necessary to put into operation the stand-by cable line and make a supply from DS 110/10 kV No. 11 since the carrying capacity of cable line from DS 110/10 kV No. 7 does not provide the requirement for the desired value of voltage drop, under that power. The increment in voltage drop results in the increase in electric loss in the system.
Experimental and LES study of unconfined jet impingement on a smooth flat heated plate with slots of different widths
Published in Experimental Heat Transfer, 2022
Dushyant Singh, Ashutosh Narayan Singh, Jishnu Handique
A schematic diagram of the jet impingement set up used in the present study is shown in Figure 2. Air is supplied through a reciprocating air compressor unit. The outlet of the compressor is connected to an air filtering device (AKARI model AF4000) and a pressure regulator for filtering dust particles and maintaining desired pressure at the inlet of the mass flow controller, respectively. The mass flow rate controller (ALICAT MCR-3000LPM-D-PAR) which maintains a constant airflow rate to the nozzle is connected to a slot type nozzle through a flexible hose pipe. The slot nozzle is attached to a height adjuster to achieve the desired nozzle to target plate spacing. The aspect ratio of 20:1 is used for the slot nozzle. The target plate is a stainless-steel foil (SS 304) having the dimensions of 250 mm × 250 mm and a thickness of 30 µm. The target plate is fixed tightly with a string arrangement attached to a rigid aluminum channel frame. Both ends of the target plate clamped with copper connectors so that it can be heated by supplying a direct current (DC) supply. Constant heat flux condition is maintained at the target plate with the help of electrical heating. A multimeter is connected across the target plate to measure the actual voltage supply for encountering voltage drop.