DC Machine Construction PDF

Construction of DC Machines Construction of DC Machines  An electromechanical device which can convert direct current (DC) electricity into mechanical energy or mechanical energy into direct current (DC) electricity is known as a DC machine.  If the DC machine converts DC...

Construction of DC Machines Construction of DC Machines  An electromechanical device which can convert direct current (DC) electricity into mechanical energy or mechanical energy into direct current (DC) electricity is known as a DC machine.  If the DC machine converts DC electrical energy into mechanical energy, it is known as DC motor. If the machine converts mechanical energy into DC electrical energy, then it is known as a DC generator. Both DC motor and DC generator have the similar construction. Construction of DC Machines  Main Parts  There are two major parts required for construction:  Stator It houses the field winding  Rotor Rotating part that rotates in magnetic field Construction of DC Machines  Main Construction Diagram Construction of DC Machines  Other parts  Yoke  Poles and Pole-Shoes  Field Winding  Armature winding  Commutator  Brushes  Bearing Construction of DC Machines  Other parts  Yoke (or Frame) ▪ Its main function is to form a protective covering over the inner sophisticated parts of the motor and carries the flux produced by the poles. Construction of DC Machines  Other parts  Poles and Pole-Shoes ▪ The magnetic poles are structures fitted onto the inner wall of the yoke with screws. ▪ The construction of magnetic poles basically comprises of two parts namely, the pole core and the pole shoe stacked together under hydraulic pressure then attached to the yoke. Construction of DC Machines  Other parts  Field Winding ▪ Made with field coils (copper wire) wound over the slots of the pole shoes. Construction of DC Machines  Other parts  Armature ▪ The armature core are provided with slots to which the armature windings made with several turns of copper wire distributed uniformly over the entire periphery of the core. Construction of DC Machines  Other parts  Commutator ▪ It is a cylindrical structure made up of copper segments stacked together, but insulated from each other by mica (thru the sides). ▪ Collects the current from the armature conductors Construction of DC Machines  Other parts  Brushes ▪ Made with carbon or graphite structures, making sliding contact over the rotating commutator. ▪ Collects the current from commutator and make it available to the stationary circuit. Construction of DC Machines  Other parts  Bearings ▪ Used in the DC machine to reduce the frictional losses. Thus, the main function of bearings in the DC machine is to support the machine shaft with minimum friction.  Construction of DC Machines  Types of Armature Winding  Wave Winding ▪ the armature coils are connected in series through the commutator segments in such a way that the armature winding is divided into two parallel paths irrespective of the number of poles of the machine  Lap Winding ▪ the armature coils are connected in series through the commutator segments in such a way that the armature winding is divided into as many parallel paths as the number of poles of the machine References  Construction of DC Machines. (n.d.). Retrieved from https://www.tutelectricalorialspoint.com/_machines/electrical_machines_constru ction_of_dc_machines.htm  Chapter #3 DC MACHINES. (n.d.). Retrieved from https://feng.stafpu.bu.edu.eg/Electrical%20Engineering/3106/crs- 15063/Files/Chapter3%20DC%20machines.pdf  Types of Armature Winding of a DC Machine - Lap Winding and Wave Winding. (n.d.). Retrieved from https://www.tutorialspoint.com/types-of-armature- winding-of-a-dc-machine-lap-winding-and-wave-winding  Haridas, R. (2014). Construction of DC Machines. Retrieved from https://www.slideshare.net/slideshow/construction-of-dc-machines/31683021#8