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Tungsten Inert Gas Welding
Published in P. Chakravarthy, M. Agilan, N. Neethu, Flux Bounded Tungsten Inert Gas Welding Process, 2019
P. Chakravarthy, M. Agilan, N. Neethu
During welding, the continuous flow of current through various components of power source leads to overheating of transformer winding and other components leading to reduced performance. The duty cycle is a ratio of the load on time allowed in a specified test interval time. Duty cycle is expressed as a percentage of the maximum time that the power source can be operated to its rated output without exceeding the prescribed temperature. A 100% duty cycle power source is designed to provide its rated output continuously without exceeding the specified temperature limit. A 60% duty cycle refers to the power source which can produce its rated output for 6 out of every 10 minutes without getting overheated. Manual welding power sources are designed for 60% duty cycle whereas automatic and semiautomatic welding power sources are rated for 100% duty cycle.
Power Transmission and Gearing Systems
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
The duty cycle is important because it determines if gearbox and motor size are based on average or peak torque and speed. Engineers should carefully and critically compare these values with the motor’s nominal and peak torque and speed ratings. The duty cycle can be cyclical or continuous. Generally, when duty cycle is less than 60% and each move takes less than 20 minutes, it is considered cyclical. If average torque and speed exceed nominal ratings, the motor requires auxiliary cooling for dissipating generated heat [9.79].
AC Motors and Generators
Published in Muhammad H. Rashid, Ahmad Hemami, Electricity and Electronics for Renewable Energy Technology, 2017
Knowing the duty cycle is important for the selection and operation of a motor. If a motor does not have 100 percent duty cycle, then it has the opportunity to cool down after each cycle of operation, whereas a motor with 100 percent duty cycle does not have such an opportunity. Also, energy consumption of a motor depends on the time that it is in operation.
RAMI Analysis for PF Power Supply System of ITER
Published in Fusion Science and Technology, 2022
Li Jiang, Ge Gao, Zhengyi Huang, Jie Zhang, Peng Wu, Xuesong Xu
The last step of the RAMI analysis is the RBD analysis, which uses blocks to represent the function of the system as defined in the FA stage and calculates the reliability and simulates the availability of the system by using BlockSim software. The input data of the RBD analysis are failure rate λ, mean time to repair (MTTR), duty cycle, and so on. The λ means the inherent frequency with which a system or component fails. The MTTR represents the average time required to repair a failed component. The duty cycle is the ratio of the operating time of the component compared to the total operating time of the system. All these input data are derived from the manufacture reliability data sheet, industry standards, and previous experience compiled in other scientific facilities. Several initial and expected input datas for simulation of RBD are shown in Table IV.
Solar supplied two-output DC–DC converters in the application of low power
Published in Automatika, 2021
If , it means that the PV voltage is less than the MPP. In this case, the duty cycle should be increased. If then the PV voltage is equal to the MPP and if it means that the PV voltage is greater than the MPP so duty cycle should be decreased.
Burst and high frequency stimulation: underlying mechanism of action
Published in Expert Review of Medical Devices, 2018
Shaheen Ahmed, Thomas Yearwood, Dirk De Ridder, Sven Vanneste
Charge per pulse is another parameter to characterize stimulation paradigm. The charge per pulse is calculated by multiplying the current amplitude by the pulse width. The charge per second, or the amount of electrical charge delivered to the spinal cord, is calculated by determining the charge per pulse and multiplying that value by the number of pulses delivered per second. The charge per pulse for burst stimulation (0.654 µC) is lower compared to that for tonic stimulation (1.03 µC). But the charge per second is higher for burst stimulation (130.8 µC/s) than for tonic stimulation (47.7 µC/s) [51]. HF stimulation is characterized by a lower charge per pulse (0.11 µC) and a higher charge per second (480 µC/s) when compared to tonic stimulation, a trend similar to the initial non-cycling burst stimulation [51]. A comparison between burst stimulation and HF stimulation reveals that burst stimulation has a higher charge per pulse but that HF stimulation delivers more charge per second. The reason for this high charge per pulse for burst stimulation is a wider pulse width, i.e. 1000 µs as opposed to 30 µs for HF stimulation. The high charge per second for HF stimulation depends on the duty cycle, i.e. the percentage of ‘on’ vs. ‘off’ time in the pulse pattern. An increase in the duty cycle increases the proportion of ‘on time’ during stimulation, increasing the charge delivered over time. The duty cycle can be increased by increasing the frequency, increasing the pulse width, or a combination of both. However, a burst SCS study demonstrated that reducing the duty cycle from 20% to 10% by decreasing the pulse width from 1000 to 500 µs did not change the pain-relieving benefits for chronic back pain patients [52]. Furthermore, a comparison between burst stimulation with a duty cycle of 20% and 500-Hz tonic stimulation with a duty cycle of 18.5% reported better outcomes in pain relief for burst stimulation, despite the fact that the overall charge delivery was higher during tonic stimulation [24]. These results suggest that burst stimulation is capable of providing pain relief irrespective of changes in the duty cycle and that the charge is not important in human studies, contrary to what was shown in animal data [24].