Unipolar tacho generator refers to a generator in which a cylindrical or disc armature rotates in a uniform magnetic field with constant polarity and induces potential in the armature.
1. The structure of the single-pole speed measuring generator is simple, there is no measurement error caused by commutation ripple and tooth harmonics, and it will not increase the time constant or filter out useful waveforms due to the need for filtering measures.
2. Good transient response and high sensitivity.
3. The unipolar speed measuring generator has excellent quality in both steady state and transient state, especially in dynamic measurement of speed, it is an ideal speed measuring element.
4. With the development of modern electronic technology and the application of microcomputers, it is a meaningful task to study the unipolar tachometer generator and its application in the measurement of rotational speed, to study the dynamic parameters and to meet the requirements of modern fast drives.
1.Ripple coefficient Unipolar tacho generator, without armature, no commutator, unlike DC tacho generator, there is voltage ripple caused by potential polygon and tooth harmonics. Monopolar tacho generator outputs DC voltage signal without ripple . It is free of commutation problems and radio interference due to commutation sparks. This is undoubtedly an outstanding advantage for the steady-state and transient test accuracy of speed measurement and the elimination of interference sources in microcomputer testing.
2. No signal area Since a unipolar motor is a single conductor moving in a uniform magnetic field, the forward and reverse running performance is exactly the same, so the output voltage is symmetrical.
3.Maximum allowable speed The unipolar tachogenerator is not limited by the voltage across the commutator like the DC tachogenerator, thus limiting the maximum speed. The maximum speed of a unipolar tachogenerator is limited only by the bearing structure, so the speed can be very high.
4.Transient response The number of conductors of a unipolar tachogenerator is N = 1, and the armature inductance is very small; since the DC voltage signal is sent without ripple, no filter circuit is required. Therefore, the transient response is good.
To sum up, the unipolar speed measuring generator has excellent quality no matter it is steady state or transient state, and it is an ideal speed measuring element.
The speed measuring generator generally requires small volume, small moment of inertia, simple structure and reliable operation. Therefore, the single-pole speed measuring generator uses a cylindrical hollow core rotor and Ban Lichuan’s permanent magnet structure. In order to ensure the uniformity of the magnetic field, it is not appropriate to use a non-magnetic pad method to overcome the armature reaction. When the current is drawn, a loop compensation method can be used. For such a low-voltage brush drainage device, in order to prevent the jump of the brush and the fluctuation of the contact pressure drop, the design of the brush device and the brush pressure is very important.
The principle of a unipolar tacho generator is that a cylindrical or disc armature rotates in a uniform magnetic field with constant polarity and induces an electric potential in the armature.