Abstract
The following chapters study principles of operation, construction, mathematical model, and basic characteristics of synchronous machines. Along with induction machines, synchronous machines belong to the group of AC machines. Their operating principles are different. The rotor of induction machines revolves at the speed slightly lower than the synchronous speed, thus their name asynchronous machines. The rotor of synchronous machines revolves at the synchronous speed.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Notes
- 1.
Electrical machines supplied the mains with line voltages U < 1 kV are also called low-voltage machines. Most low-voltage machines have star connected stator windings with floating star point. Namely, the star connection of the three phases is not connected to any other node. In most cases, the star point is even inaccessible, namely, it is not made available to the user. Machines with stator voltages in excess to 1 kV may have their star point connected to the neutral or to the ground by means of a series impedance. This connection reduces the overvoltage stress. In most cases, the impedance used for grounding the star point has a minor effect on the equation i a  + i b  + i c  = 0.
- 2.
Anisotropic – having different properties in different directions. For example, anisotropic ferromagnetic may have different permeability in direction of axes x, y, and z.
- 3.
In synchronous motors supplied from three-phase inverters with pulse width modulation, there is a certain current ripple, a high-frequency component of the stator current with an amplitude of 0.02 … 0.03 I n and with the frequency which is equal to the switching frequency of power transistors. Due to this nonsinusoidal supply, there are some small, high-frequency variations of the magnetic induction within the rotor circuit, notwithstanding the fact that the fundamental flux component revolves in synchronism with the rotor.
- 4.
Specific torque is the ratio T em /m, the quotient of the torque, and mass of the machine. Alternatively, specific torque can be defined as T em /V, the quotient of the torque and volume.
- 5.
Starting from zero, the rated current I n can be reached in 1/7,000 s.
- 6.
Synchronous machines with permanent magnets that are not placed on the rotor surface, and do not face the air gap, but reside instead in dedicated holes and chambers carved within inner regions of the rotor magnetic circuits, located further away from the surface and closer to the shaft are called buried magnet or interior magnet machines.
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 2013 Springer Science+Business Media New York
About this chapter
Cite this chapter
Vukosavic, S.N. (2013). Synchronous Machines. In: Electrical Machines. Power Electronics and Power Systems. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-0400-2_18
Download citation
DOI: https://doi.org/10.1007/978-1-4614-0400-2_18
Published:
Publisher Name: Springer, New York, NY
Print ISBN: 978-1-4614-0399-9
Online ISBN: 978-1-4614-0400-2
eBook Packages: EnergyEnergy (R0)