4.6.1 Self-inductance arrangements Thus the sensitivity, s, is now a conatant, and the input and the output have an approximately linear relationship In practice, we often select△δ/δ≤0.1. This kind of transducer is suitable to the measurement of small displacement, usually within 0.001 to lmi Inductance can also be changed by changing and
4.6.1 Self-inductance arrangements Thus the sensitivity, S , is now a conatant, and the input and the output have an approximately linear relationship. In practice, we often select / 0.1 . This kind of transducer is suitable to the measurement of small displacement, usually within 0.001 t o1m m . Inductance can also be changed by changing A0 and W
4.6. 1 Self-inductance arrangements coil S=axb Iron core Varying-permeable-area-type Solenoid-type Displacement L,,+L Linear variable differential transformer(LVDT Fig 4.16 Permeance-varying inductive transducer
Fig. 4.16 Permeance-varying inductive transducers Varying-permeable-area-type Solenoid-type Linear variable differential transformer(LVDT) 4.6.1 Self-inductance arrangements
4.6.1 Self-inductance arrangements p turbine shaft Inductive choke Nonmagnetic coating Housing (a) Ir ron core xcitation Leads Measured distance To stage-two circuitry Valve rod Fig. 4. 17 Self-inductance transducers for various applications
4.6.1 Self-inductance arrangements Fig. 4.17 Self-inductance transducers for various applications
4.6.1 Self-inductance arrangements 2. Eddy-current transducers o When a metal conductor is placed in a changing magnetic field or is moving in a magnetic field, an electrical current will be induced within the conductor. This current is self-closed within the metal conductor. and is therefore referred to as electrical eddy-current or, simply, eddy-current
2. Eddy-current transducers ❑ When a metal conductor is placed in a changing magnetic field or is moving in a magnetic field, an electrical current will be induced within the conductor. This current is self-closed within the metal conductor, and is therefore referred to as electrical eddy-current or, simply, eddy-current. 4.6.1 Self-inductance arrangements
4.6.1 Self-inductance arrangements Due to the flux by the eddy-current, the equivalent resistance of the coil will change, whose magnitude is dependent not only on the gap o but also on the resistivity of the metal conductor. p, its permeability, u,and the frequency of the exciting current,. Changing any one of these parameters yields the change in coils equivalent resistance, and this can be used for different applications
Due to the flux by the eddy-current, the equivalent resistance of the coil will change, whose magnitude is dependent not only on the gap but also on the resistivity of the metal conductor, , its permeability, , and the frequency of the exciting current, . Changing any one of these parameters yields the change in coil’s equivalent resistance, and this can be used for different applications 4.6.1 Self-inductance arrangements