Description : Magnet chatter or 'pumping' occurring in a magnetic contactor can be caused by ______________. A. dirt or grease on pole faces B. mechanical interference in the contacts C. chattering contacts on the control relay D. magnetic lock out of the contacts
Last Answer : Answer: C
Description : A balanced three-phase, 50 Hz voltage is applied to a 3 phase, 4 pole, induction motor. When the motor is delivering rated output, the slip is found to be 0.05. The speed of the rotor m.m.f. relative to the rotor structure is (A) 1500 r.p.m. (B) 1425 r.p.m. (C) 25 r.p.m. (D) 75 r.p.m.
Last Answer : (D) 75 r.p.m.
Description : In the illustration, the component VR2 on the A1 AMPLIFIER MODULE is _________. EL-0060 A. a zener diode to regulate the +9 volt power supply from common B. a variable resistor diode to control the output to terminal ... 2 at 9.1 volts DC D. a tunnel diode with a breakdown voltage of 6.6 Volts DC
Description : In the illustration, the component VR1 on the A1 AMPLIFIER MODULE is _________. EL-0060 A. a zener diode to regulate the +9 volt power supply from common B. a variable resistor diode to control the output to ... terminal 9 at 6.6 volts DC D. a tunnel diode with a breakdown voltage of 6.6 Volts DC
Last Answer : Answer: A
Description : In the illustration, the component VR1 on the A1A1 PCB is _________. EL-0060 A. a zener diode to regulate the +9 volt power supply B. a variable resistor diode to control the output to terminal 9 that controls ... terminal 9 at 6.6 volts DC D. a tunnel diode with a breakdown voltage of 6.6 Volts DC
Description : The voltage output of an AC generator is accurately controlled by _____________. A. changing the sensitivity of the prime mover to large changes in voltage B. varying the reluctance of the air gap C. varying the DC exciter voltage D. shorting out part of the armature windings
Description : The output voltage of a three-phase alternator is regulated by the _____________. A. AC voltage to the armature B. AC voltage to the field C. DC voltage to the armature D. DC voltage to the field
Last Answer : Answer: D
Description : What are the advantages of salient pole type of construction used for synchronous machines?
Last Answer : 1. They allow better ventilation. 2 The pole faces are so shaped radial air gap length increases from the pole center to the pole tips so that flux distribution in the air gap is ... 3 Due the variable reluctance, the machine develops additional reluctance power, which is independent of excitation.
Description : The introduction of interpoles in between the main pole improves the performance of d.c. machines, because (A) The interpole produces additional flux to augment the developed torque. (B) The flux waveform is ... armature is removed. (D) A counter e.m.f. is induced in the coil undergoing commutation.
Last Answer : Ans: D Counter e.m.f is produced, it neutralizes the reactive emf.
Description : If a magnetic controller contact fails to pick up when the operating coil is energized, one possible cause may be _______________. A. low spring pressure B. low voltage to the coil C. the residual magnetism of the contact faces D. dirty contact faces
Last Answer : Answer: B
Description : If a DC motor runs faster than designed, with all other conditions being normal, the possible cause could be a/an ______________. A. shorted shunt field coil B. open armature coil C. reversed commutating pole D. overload
Description : Which of the listed conditions will occur if the polarity of the field poles and the direction of current to the brushes of a DC motor were both reversed? A. The motor would not start. ... direction of rotation of the armature would be unchanged. D. The field pole windings would become overheated.
Description : Which of the following statements describes what will happen when both the polarity of the field poles, and the direction of current to the brushes of a DC motor are reversed? A. The motor will ... of rotation of the armature will remain the same. D. The field pole windings will become overheated.
Description : Which of the following types of DC motors has its field connected in parallel with its armature? A. Counter EMF B. Shunt C. Salient pole D. Series
Description : Which one of the following statements for a dc machine which is provided with inter pole winding (IW) as well as compensating winding (CW) is correct a) Both IW and CW are connected in ... parallel with Armature winding d) CW connected in series but IW is connected in parallel with Armature winding
Last Answer : Ans: Both IW and CW are connected in series with Armature winding
Description : In DC generators, armature reaction is produced actually by (A) Its field current. (B) Armature conductors. (C) Field pole winding. (D) Load current in armature.
Last Answer : Ans: D Because load current in armature gives rise to armature mmf which react with main field mmf.
Description : A 4 pole lap wound dc shunt motor rotates at the speed of 1500 rpm, has a flux of 0.4 mWb and the total number of conductors are 1000. What is the value of emf? (A) 100 Volts. (B) 0.1 Volts. (C) 1 Volts. (D) 10 Volts.
Last Answer : Ans: D Given N = 1500 rpm, Φ = 0.4 mWb, Z = 1000, P = 4, & A= 4 Therefore, Eb = NΦPZ / 60 A = 1500 x 0.4 x 4 x 1000 x 10^-3 / 60 x 4 = 60/6 = 10 volts
Description : How dense is it for someone to have their penis curved in some direction?
Last Answer : Not for me, but according to statistics, 63% of people curve to something, so you’re not alone with that, don’t worry! The girls love it too.
Description : What is the kind of structure with a thin layer of material spread into a curving shape?
Last Answer : What is the answer ?
Description : Who apparent curving of winds due to earths rotation is the?
Description : Which of the following terms refers to the shaft of the long bone? a) Diaphysis The diaphysis is primarily cortical bone. b) Epiphysis An epiphysis is an end of a long bone. c) Lordosis ... an increase in lumbar curvature of spine. d) Scoliosis Scoliosis refers to lateral curving of the spine.
Last Answer : a) Diaphysis The diaphysis is primarily cortical bone.
Description : Which of the listed conditions might contribute to very rapid wearing of a DC machine's commutator bars? A. A grounded commutator bar B. Using improper carbon brushes C. Aligning the front and rear mica V-rings improperly D. An open circuit in the armature
Description : Which of the methods listed is used to maintain the division of load between two compound-wound, DC generators operating in parallel? A. The shunt fields are interconnected. B. The shunt ... generators are connected in series. D. The equalizer connection parallels the series fields of all machines.
Description : Enlist the types of dc machines?
Last Answer : Answer: D.C. machines are classified into two types 1) separately excited 2) self excited which is further classified into 1)series 2)shunt and 3)compound(which is further classified into cumulative and differential).
Description : What is the minimum recommended absorption coefficient value for AC and DC rotating machines?
Last Answer : Tips: a. IR value decreases some what with an increase I applied voltage. However for machines in good condition substantially the same IR is obtained for any test voltage ... a value which after correction for temperature, may be compared with the recommended minimum value of IR.
Description : What are the minimum recommended PI values for AC and DC rotating machines?
Last Answer : Following minimum recommended PI values criteria is to be followed. a. 1.5 for class – A insulation. b. 2.0 for class – B insulation. c. 2.5 for class – F insulation.
Description : What advantage is gained by using pole pieces with curved faces in the D’Arsonval meter movement?
Last Answer : Two-position and three-position.
Description : The pole faces of U-shaped magnet in a moving coil galvanometer are made concave to a) decrease the strength of magnetic field b) create a non-uniform magnetic field c) make the magnetic field radial d) All of these
Last Answer : c) make the magnetic field radial
Description : Why are socks softer and smoother on the outside than on the inside?
Last Answer : answer:I haven't noticed this - maybe it's you. I wear mostly Gold Toe fluffy socks - they're smooth inside and out. My sweat socks - don't remember what brand name they are, one of the ... and out. So I honestly haven't experienced the issue you are complaining about. Where do you get your socks?
Description : Will a sports bike or a cruiser ride smoother on the highway?
Last Answer : It depends on suspension settings, but sport bikes are generally set much stiffer and can be very uncomfortable on the highway. Cruiser are made for just that! Try some out and see what you like best.
Description : Where can I find smoother Velcro strips?
Last Answer : I don’t know about the specific product that you’re talking about, but I can tell you that craft stores usually have a large selection of velcro.
Description : In a stick shift car, is it easier on the clutch to pop it and get some jerkiness, or to ride it a bit for a smoother transition?
Last Answer : answer:The clutch is designed to slip, but it's also designed to wear slightly over time. If you ride it too much you can conceivably wear it out in a couple of hours. If you decide to ... get familiar with the car faster and really lessen the chances of causing damage. Good luck with the dispute.
Description : The Bezier curve is smoother than the Hermite cubic spline because it has _________ orderderivatives. a.lower b.higher c.lower and higher both d.none of the above
Last Answer : b.higher
Description : what is the where it raines and rock gets smoother called?
Last Answer : sedimentary facies
Description : What kind of body lotion will make my skin smoother?
Last Answer : Some of the best lotions are GOld Bond and Vaseline. Alleve is also very good as well. The bast way is to read the bottles when deciding for the best kind of body lotion or cream.
Description : During ageing of fluid carrying pipes, the (A) Pipe becomes smoother with use (B) Friction factor increases linearly with time (C) Absolute roughness decreases with time (D) Absolute roughness increases linearly with time
Last Answer : (D) Absolute roughness increases linearly with time
Description : In regard to carbide burs; the more number of cutting blades and low speed will result in: A. Less efficient cutting and a smoother surface B. Less efficient cutting and a rougher surface C. More efficient cutting and a smoother surface D. More efficient cutting and a rougher surface
Last Answer : A. Less efficient cutting and a smoother surface
Description : An open shunt field in a direct current machine may be located by connecting the field circuit to an external power source, equal to the rated field voltage or less, and tested with a voltmeter from ... C. any suitable ground to any available line lead D. any field pole to each field coil lead
Description : You are attempting to parallel two AC generators and the synchroscope pointer stops at a position other than 0°. If you close the circuit breaker at this moment _____________. A. the incoming ... hazardous condition will be created by the incoming machine being at a higher frequency than the bus
Description : A dc series motor driving and electric train faces a constant power load. It is running at rated speed and rated voltage. If the speed has to be brought down to 0.25 p.u. the supply voltage has to be approximately brought down to (A) 0.75 p.u (B) 0.5 p.u (C) 0.25 p.u (D) 0.125 p.u
Last Answer : A dc series motor driving and electric train faces a constant power load. It is running at rated speed and rated voltage. If the speed has to be brought down to 0.25 p.u. the supply voltage has to be approximately brought down to 0.5 p.u
Description : What are the points contributes in insulation resistance of the motor?
Last Answer : If the measured insulation resistance of the motor is less than 1 MΩ / kV with a minimum of 1MΩ, when the machine is cold it is to be dried out before full voltage is applied to the terminals of ... voltage. f. Residual charge in the winding. g. Ageing of the insulation. h. Mechanical stresses.
Description : What two factors can cause output dc voltage to change?
Last Answer : Ac line voltage and a change in load resistance.
Description : Why does using ac vice dc bias voltage result in a stronger output signal?
Last Answer : Because an ac bias voltage of the proper frequency and level places the input signal away from both steps in the magnetism curve. The result is two undistorted output signals that are combined into one strong output.
Description : What component causes a generator to produce dc voltage rather than ac voltage at its output terminals?
Last Answer : A commutator
Description : The output from a full wave rectifier is (a) A pulsating uni-directional current (b) A DC voltage (c) Zero (d) An AC voltage
Last Answer : a) A pulsating uni-directional current
Description : An AC supply of 230 V is applied to half wave rectifier circuit. A transformer turns ratio is 20 : 1. Find i) Output DC voltage (ii) Peak Inverse Voltage (PIV)
Last Answer : Solution:
Description : In a three phase controlled bridge rectifier with an increase of overlap angles the output dc voltage
Last Answer : In a three phase controlled bridge rectifier with an increase of overlap angles the output dc voltage decreases
Description : In dc choppers for chopping period T, the output voltage can be controlled by FM by varying (A) T keeping Ton constant (B) Ton keeping T constant (C) Toff keeping T constant (D) None of the above
Last Answer : In dc choppers for chopping period T, the output voltage can be controlled by FM by varying T keeping Ton constant
Description : The ripple voltage in the output of a single phase half wave rectifier with 10 V rectified dc voltage with resistive load and without filter will be • 12.1 volt • 1.21 volt • 0.482 volt • 4.82 volt
Last Answer : The ripple voltage in the output of a single phase half wave rectifier with 10 V rectified dc voltage with resistive load and without filter will be 12.1 volt
Description : When three-phase AC power is supplied to the device shown in the illustration, the output will be _____________. EL-0063 A. single-phase AC B. split-phase AC C. three-phase DC D. unidirectional DC