EXPERIMENT NO. 9
AIM: To Study the speed control of D.C. Shunt motor by(i) Field control method.
(ii) Armature control Method.
DC Shunt motor
5-HP, 1500 rpm, 1
16.7 amp, 220 V
Graph 20.2 now can be used as a calibration chart for the shunt circuit of Fig. 20.4.
Now set the O-IO-kll potentiomet~r (Rx) to three random values and record the
resulting value of 1Min column one of Ta
Imeter movement (mA)
f r II! I ! IIIII I,II I,IIII ! I
11 , t I ~ f,
I , I , ~I
Draw a meterscale for your ohmmete
Construct circuit of Fig. 20.2.
Connect the probes points PI and P 2 together and adjust the power supply until the
meter movement reads I rnA. Hold the probes apart (open-circuit
EXPERIMENT dc 19
How does this level of the current I compare with the calculated and measured values of the
1:1",'(;3 \Co): 1"7, ~ A
f'","T "3<.e.) 1~,lomrA
2. Referringto Fig. 19.1,if Rl and R
WHEATSTONE BRIDGE AND Il-Y CONVERSIONS
(b) Calculate the source current I and the voltage Vab
using any method other than a
~- Y conversion (that is, mesh analysis, nodal analysis, and so on). Record the results in column
one of Table 19.4. Use RA = R
1. Becomefamiliar with the construction and terminal characteristics of the
2. Usea commercialWheatstonebridge to measurean unknown resistance.
3. Apply a ~- Y conver
(a) Construct networkof Fig. 19.3.Insertthe measured
setthe potentiometer the maximumresistance
Whatconclusions you draw from the preceding
(a) Construct circuit of Fig. 18.6.
~k.a + R2measured
What is the theoretical valu~ .oftbe voltage V2? Use measured
DESIGN OF A dc AMMETER AND VOLTMETER AND METER LOADING
Testing the Designed Voltmeter:
(b) Connectyour newly constructedvoltmeter in parallel with a voltage,source
and the DMM as shown in Fig. 18.4. Set the variable resistorto Rswith your DMM
EXPERIMENT dc 18
The basic metermovement a current-sensitive
device.Its constructionconsistsof a coil suspendedin a ma
51' = S-(Q.3MS)
(e) Write the mathematical expressionsfor the voltage vL and current iL during the
storagephase (assumingRf = On).
v = 5V
"ri 3 z\:-:en =
R-L AND R-L-C CIRCUITS WITH A dc SOURCE VOLTAGE
Compare the measuredlevels with the calculated results of part 3(a).
(c) Calculate the energys
Course and Section:
1. Verify conclusions regarding the behavior of inductors in a steady-state
2. Observe the characteristics of an inductor and capacitor in the same dc
network under steady-s
Calculate Rl using Ohm's law: Rl = VL/I.Recordthe result in the last column of
Is it possible a practical
inductor haveR, = 0 m Explain.
(d) Calculate the charging time (57) for the voltage across the capacitor, CT and
record in Table 16.4.
(e) Using a watch, record (to the best of your ability) the voltage across the series
capacitors at th
terminals a andb for the networkto the left of the capacitor.
~ "1- E'"
02 .~ ~
-=. ~ O~ v
t It> 0 ~ ~"'-'1.
EXPERIMENT 16 8
(e) Using a watch, record (to the best of your ability) the voltage across the capacitor
at the time intervals appearing in Table 16.2 after the switch is closed. You may want to make a test
run before recording the actual levels.
1. Determine the time constantof an R-C network.
2. Obtain the charging voltage of two capacitors in parallel.
3. Obtain the charging voltage of two capacitors in series.
4. In eachcas
(e) Disconnect supplyandmeasure voltageacross disconnected
Is therea reading?
C " QY~ IS sfor-e.c,(
; 1.'1Th -e. C~ pac,(
l/1o+-e:. V ~ ~/ c.
(f) Shortthe capacitor
1. Calculate the time constantof a seriesR-C circuit.
2. Calculate the circuit current and the capacitor voltage for various R-C
circuits after five time constants.This in effect def
Calculate the currents fRI' fR2' and fR3
using the measured voltage and resistor values
and insert in Table 14.3 as the measuredvalues. Be sure to include a minus sign if the current direction is opposite to that defined by the pola
NORTON'S THEOREM AND CURRENT SOURCES
Vary the supply voltage until the DMM indicates the value IN from part 2(b). Record
the values of E and IN in Fig. 13.6(b). Next remove the DMM and, using it as an ohmmeter, set the
Do the results verify the source conversion theory?
~So\"T.e, ~ ~c. fCl.rCAMT
For thenetworkof Fig. ~
(a) Find INby determining the reading of an ammeterplaced betweenpoints a and b.
EXPERIMENT dc 13
(k) Does the plot of Graph ~reveal
IL is fairly constant for the range of chosen
tr"'" , ~
yo ~ .
(I) Wouldyou consider networkof Fig. l~a
figurationof Fig. ~? Makea
R71J .2.'4~.n., E71J 3$.~ tJ
(c) Is the power determined in part (b) the maximum power that could be delivered to a reo
sistor betweenterminals a andb? If not, what is the maximum power?