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Introduction to Electric Motors
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
The stall torque is the torque that a motor produces at zero rotating speed where Pout= 0. The stall torque, also known as locked rotor torque (LRT), can be measured with the rotor being locked. For a DC motor, the motor torque has a linear relationship with the motor rotating speed. The maximum torque occurs at zero rotating speed and zero torque occurs at a maximum rotating speed. For an IM, the stall torque can be calculated as [1.20] Ts=C1k2(Pin,s−Ps−Psc)ns
Small Motors
Published in Dorin O. Neacşu, Automotive Power Systems, 2020
Figure 12.19 illustrates this characteristic with an example. For instance, stall torque is the maximum torque that can be externally applied to the shaft and cause the motor to stop rotating. When there is no rotation in the motor, the wound coils are acting as a fixed resistance. For continuous running, the stall torque should not be exceeded since this is the maximum torque at which overheating will not occur. For intermittent use, higher torque is possible for short intervals of time, during transients. The torque-speed characteristics also show that the available torque decreases at higher speed with the maximum available speed at no-load operation. The actual curve for the maximum torque at each speed depends on the actual motor technology, which is sometimes linear, sometimes slightly curved, as suggested in Figure 12.19.
Principles of Energy Conversion
Published in Hamid A. Toliyat, Gerald B. Kliman, Handbook of Electric Motors, 2018
Hamid A. Toliyat, Gerald B. Kliman
Peak torque is the value of torque that the motor can deliver to the load on a repetitive basis without overheating the motor or demagnetizing the field magnets. It is usually less than the stall torque rating, since operating the motor at stall even for short periods of time will almost always result in damage to the motor. To test for stall torque, constant voltage is applied to the motor and torque is gradually increased to the point where speed is reduced to zero. Motors are seldom tested to this point because internal heating causes the point to move during the test.
An optimal selection of slot/pole combination and its influence on energy efficient PMSM for submersible water pumping applications
Published in International Journal of Ambient Energy, 2023
Anand Mouttouvelou, Vinod Balakrishna, Sundaram Maruthachalam, Suresh Muthusamy, Hitesh Panchal, Meenakumari Ramachandran, Vennila Ammasi
The choice of electric motor for pump applications is selected based on performance requirements and economic aspects. Since the SBLPMM uses the same stator construction as the Induction motor with three-phase distributed winding, no additional stator manufacturing is required for the new product line. Yet, for the construction of the permanent magnet rotor new manufacturing assemblies are required. The stall torque of the induction motor makes it easy for direct grid operation without involving electronically controlled converters which are a mandate for the operation of the SBLPMM. Though the initial cost of the SBLPMM is comparatively high when compared with the SIM, the operating cost is lower. The specifications of the SBLPMM considered in this research work are shown in Table 1.
Excavation by snake robots with fins and a drill
Published in Advanced Robotics, 2023
Hiromu Yoshida, Taro Yamazaki, Mizuki Nakajima, Motoyasu Tanaka
Figure 8 illustrates the drilling unit. As shown in Figure 8(b), the drilling unit consists of two motor cases, two covers, a bit holder, rubber sheet, drill bit, and tightening ring. A rubber sheet is inserted between the holder and drill bit, and the tightening ring tightens the drill bit to the holder. The motor case, cover, and bit holder are made of PLA plastic using a 3D printer. To change the direction of the drill bit by rotating the motor of the joint in the ground, we selected a small and lightweight drill bit. A drill bit (R29 × 45T ) [20] is a bit used in rock bolts for reinforcing slopes and tunnels. We selected the motor for the drilling unit from the Dynamixel motor series, which can communicate angle, angular velocity and current. The average value of soil adhesion obtained from [23] is 3.34 N/cm, the area of the slip surface between the soil and the bit is 6.13 cm, and the distance between the slip surface and the motor's axis of rotation is 0.0225 m. The torque required for the motor calculated from these values is 0.461 Nm. However, due to the randomness of actual soil parameters and the presence of hard gravel and other materials, large instantaneous counter torques may be applied. Therefore, we selected XM540-W270R (stall torque 10.6 N), which meets the required torque and has the most torque margin.
Analysis of over cut in electrical discharge machining of nickel-based alloy using Taguchi approach
Published in Materials and Manufacturing Processes, 2023
Rakesh Kumar, Vinod Yadav, Lavish Rawal, Upendra Kulshrestha
To achieve accuracy in manufacturing of hard material is a big hurdle, hence, objective of present study is to overcome this challenge by reducing OC. Electronika made EDM machine was used to accomplish the experiments on Inconel 718 alloy with a z-axis EDD arrangement depicted in Fig. 1. An EDD-based experimental arrangement consisting of mild steel frame, DC motor along with its speed controller (0–100 RPM), non-contact proximity sensor (18 M NPN with sensing distance 8 mm), RPM indicator (range 0–999) and tool holder. DC motor specifications are as follows: RPM −100 at 12 V; Voltage − 4 V to 12 V; Stall torque − 50 Kg-cm at stall current of 6.9 Amp.; Shaft diameter − 8 mm; Shaft length − 25 to 30 mm; Gear assembly – Spur. An EDD set up has been used for providing rotation to tool electrode. Rotation of tool electrode enhances flushing of debris material in machining by introducing centrifugal force within the spark gap. This will help in reducing machining time i.e., improving machinability.[31] Cu electrodes of diameters 4-, and 6-mm with helical grooves (helix angle of about 10°) were used to accomplish EDD method. Presence of helical grooves enhances the machining performance.[32] The parameter retained to be constant throughout the EDD of Inconel 718 alloy with thickness of material as 3 mm.