Separately Excited DC Generator
Performed by : Duldulao, Caryl Xyra L.
Date Performed : November 27, 2012
Date Submitted : December 4, 2012
Engr. Timoteo V. Limsiaco
* Digital Wattmeter (DWM)
* Digital Multi-meter (DMM)
* Plastic Coupling
* 10 Alligator Clips (Big Wire)
* 10 Banana Plug (Big Wire)
* 1 Banana Plug with Flat Plug Combination
II. WIRING DIAGRAM:
Circuit Diagram of the Connections
Actual Wiring of the Shunt Generator with Connected Loads
III. DATA AND RESULTS:
VS| Loads| VFL| IA| IF| IL| Eg| VnL| %VREG|
30 V| 1| 40.2| 1.3| 0.13| 1.17| 1.69| 40| 0.74%|
40 V| 2| 48.2| 3.1| 0.18| 2.92| 4.03| 40| 20.398%| 50 V| 3| 55.5| 4.6| 0.22| 4.38| 5.98| 40| 27.9%|
60 V| 4| 59.7| 6.31| 0.27| 6.04| 8.203| 40| 32.998%| 70 V| 5| 60.6| 8.22| 0.31| 7.91| 10.686| 40| 33.99%|
PDEV| PDEL| | RA| 1.3 Ω|
52.39 W| 1.977 W| | Rf| 212 Ω|
149.42 W| 11.767 W| | RSE| 0.6 Ω|
255.3 W| 26.192W| | | |
367.707 W| 49.456W| | | |
448.132 W| 84.526 W| | | |
* We created the circuit according to the circuit diagram instructed to us to do.
* Before we start, measuring the armature resistance and the field winding resistance is necessary if it is working properly.
* We then started to make the shunt generator for a test run without the load to measure the RPM using the tachometer.
* We consulted the nameplate to determine if the values we have are proper.
* We then connected the load and started making the generator perform its function.
* The DMM is used to determine the values for each region that need to be measured and wrote it down to our table of data and results.
A kind of excitation of generators where the magnetic field of the main poles is excited by a current supplied to the windings of the main poles from the armature (rotor) winding. A self-excited generator is thus distinguished from a separately excited generator, in which the windings of the main poles receive current from an external source. Self-excitation is made use of most often in DC generators. When a self-excited generator is started, the initial current in the field winding is produced by the electromotive force (emf) induced in the armature winding by the residual magnetic field of the main poles. To sustain self-excitation, the initial current must reinforce this field. The additional magnetic flux increases the emf in the armature and, consequently, the current in the windings of the main poles.
1. What would happen if there is no load in the experiment?
* The generator would run at a constant speed with the two-pole switch kept open.
2. What is a separately excited DC generator?
* A separately excited DC generator is a generator where its field current may be obtained from an external source, such as a battery or a rectifier, or variac.
3. In the experiment ,did the terminal voltage increase or decrease when additional load was placed on the generator?
* Using the calculated values as the basis for our answer, we...