Induction current

Interrupting when the motor is in a locked rotor condition (Section 1,2) or is still accelerating and carrying a highly inductive current of the order of six to seven times the rated current at a p.f. of about 0.2-0,3,... 

Slamecka, M.E.. Interruption of small inductive currents Working Group 13.02 of Study Commiliec 13 (Switching Equipment). Electro, No. 95 (1983). 

Induktions-hMrten, n.(Metal.) induction hardening. -ofen, m. induction furnace, -rolle, -spule,/. induction coil, -strom, m. induction current, -vermogen, n. inductive capacity, -wirkung, /. inductive effect, -zeit, /. period of induction. 

Joule s Researches (1848-1880).—(a) The heat produced in a coil of wire by induction currents set up on rotation between the poles of an electromagnet was communicated to water in which the coil was placed, and was compared with the work done by falling weights in rotating the coil (1848). 

CoilCraft CS1200 Sensor CoilCraft 35 A Inductive Current Seri... 

E. Baum, Some Considerations for Inductive Current Sensors, Sensor and Simulation Note 59... 

At resonance, the magnetization vector M precesses about the vector B, i of the alternating field according to eq. (1.34). As a result, a component of transverse magnetization My.j rotates in the x y plane at the Larmor frequency v0. If a receiver coil is placed in the x y plane, the rotating magnetic vector Myj induces an electromotive force measurable as an inductance current. This process is called nuclear induction [5, 8]. The orientation of the coil axis will affect the phase relative to B1 i but not the magnitude of the induction current. 

Maximum induction current due to resonance between rf field and Larmor precession corresponds to maximum absorption of energy. Thus, the plot of the induction current in the v direction (n/2 ahead of the vector Bl i ) as a function of frequency is the NMR... 

Before and after resonance, there are magnetization components of opposite sign 180° out of phase and in phase (+ u and - u direction) with the rf field B1 i (Fig. 1.8). At resonance, there is no magnetization in the u direction. If the receiver coil obtains the inductance current in phase with Bli (the u direction), a dispersion curve (Fig. 1.9) results, called the u mode. When the absorption or out of phase spectrum ( ) reaches its maximum (/ind (oj) = max.), the dispersion or in phase spectrum ( ) goes through zero and changes its sign, as illustrated in Fig. 1.9. 

In the conventional NMR experiment, a radio-frequency field is applied continuously to a sample in a magnetic field. The radio-frequency power must be kept low to avoid saturation. An NMR spectrum is obtained by sweeping the rf field through the range of Larmor frequencies of the observed nucleus. The nuclear induction current (Section 1.8.1) is amplified and recorded as a function of frequency. This method, which yields the frequency domain spectrum f(ai), is known as the steady-state absorption or continuous wave (CW) NMR spectroscopy [1-3]. 

It was not until alternating voltages (AC) were applied to the electrodes that the polarization was eliminated and consistent results were obtained. Theoretically, it is the impedance not the resistance of the electrode system that should be measured. When an AC voltage is applied across a conductor, there can be an inductive current controlled by the inductance of the conductor, a capacity current controlled by its capacity and a resistive current controlled by the conductor s resistance. The situation is further complicated by the fact that there is a phase difference between the three currents, the inductive current leads the resistive current and the capacity current lags behind the resistive current and thus the measurement of the electrode impedance would appear to be rather difficult. In practice, however, due to the geometry of the electrode system, the inductive and capacity components of the current are made extremely small compared with the resistive current and thus the measurement of resistance can be made using the total current that is in phase with the applied voltage. 

Kafy, S. and Tulandi, T. (2007) New advances in ovulation induction. Current Opinion in Obstetrics el Gynecology, 19, 248-252. 

Making use of results obtained earlier in this chapter (eq. 1.154), we have the following solution for the induction current ... 

It is appropriate to emphasize again that according to the Biot-Savart law the quadrature component of the magnetic field arises from currents induced in a medium for which the phase is shifted by 90° with respect to the current in the dipole source, while the inphase component is the algebraic sum of the primary and secondary fields. The inphase component of the secondary field is contributed by induction currents in the medium shifted by 180° or 0° with respect to the source current. 

Figure 2.6. Definition of an elementary toroid in which induction current flows.

Then, for the electromotive force and active resistance in such the probe caused by inducted currents we have ... 

The first term of eq. 6.7 does not depend on a probe position, since it describes a signal caused by induction currents in the borehole with conductivity equal to... 

Jet methods of coating application presume blasting of the heated article by a jet of gas-powder mixture. This technology is convenient for covering items of large size or length, or their separate parts, e.g. in diflicult-to-access cavities, hollows and slots. The jet method is typically used to coat inner surfaces of pipes and vessels heated in ovens or by induction currents. 

The channel induction furnace consists of a big, thermally isolated bucket, equipped with an isolated top-lid for introduction of the charge (Figure 2.15). The bottom is equipped with one or more U-channels. Around these channels is a water-cooled induction coil, which heats and circulates the metal. The induction current has the frequency of the local electricity grid. The furnace is generally mounted in an hydrauUcally tiltable frame for tapping or maintenance operations. Pressurised and non-tilting furnaces are also in use. 

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