Description : Which of the following iron core electromagnets creates the greatest amount of magnetic flux: w) 1,000 coils, 2 amps of current x) 250 coils, 7 amps of current y) 700 coils, 3 amps of current
Last Answer : ANSWER: Y -- 700 COILS, 3 AMPS OF CURRENT
Description : The current coil of a single-phase energy meter is wound on (a) One limb of the laminated core (b) Both the limbs of the laminated core with same number of turns (c) Both the limbs of the laminated core with different number of turns (d) The centre of the limb on the laminated core
Last Answer : The current coil of a single-phase energy meter is wound on Both the limbs of the laminated core with same number of turns
Description : In a compound-wound motor, a portion of the line current flows through the _____________. A. inertial poles B. stator C. shunt field coils D. frame
Last Answer : Answer: C
Description : If the permeability of the core of a coil increases, what happens to (a) inductance and (b) true power in the circuit?
Last Answer : (a) Inductance increases; (b) true power decreases.
Description : Two coils have a mutual inductance 0.005H. The current changes in the first coil according to the equation `I=I_(0) sin omegat "where" I_(0)=10A and o
Last Answer : Two coils have a mutual inductance 0.005H. The current changes in the first coil according to the equation `I ... (pi//x)` volts. Find the value of x.
Description : Shading coils are installed on AC full-voltage starters to _____________. A. eliminate contact chatter B. dissipate opening contact arcs C. delay current build up in the holding coil D. protect the motor windings from momentary starting current overload
Last Answer : Answer: A
Description : A variable shunt, connected across the series field coils of a DC compound wound generator, to permit adjustment of the degree of compounding, is called a _____________. A. divider B. diverter C. converter D. rheostat
Last Answer : Answer: B
Description : A 8-pole, DC generator has a simplex wave-wound armature containing 32 coils of 6 turns each. Its flux per pole is 0.06 Wb. The machine is running at 250 rpm. The induced armature voltage is (A) 96 V (B) 192 V (C) 384 V (D) 768 V
Last Answer : A 8-pole, DC generator has a simplex wave-wound armature containing 32 coils of 6 turns each. Its flux per pole is 0.06 Wb. The machine is running at 250 rpm. The induced armature voltage is 384 V
Description : The coils of D.C. motor starter are wound with wire of?
Last Answer : The coils of D.C. motor starter are wound with wire of manganin.
Description : A coil is wound with 400 feet of No. 16 tinned copper wire and connected to a 12 volt battery. What is the current if the resistance per 1000 feet of No. 16 tinned copper wire is 4.26 ohms? A. 4.8 amps B. 7.06 amps C. 10.65 amps D. 11.27 amps
Description : A coil is wound with 200 feet of No. 16 tinned copper wire and connected to a 12 volt battery. What is the current if the resistance per 1000 feet of No. 16 tinned copper wire is 4.26 ohms? A. 1.14 amps B. 7.04 amps C. 10.22 amps D. 14.08 amps
Last Answer : Answer: D
Description : The simplest method of controlling the terminal voltage of compound-wound DC generator is with a _____________. A. hand-operated field rheostat connected in series with the shunt field circuit B. ... in series with the load D. balance coil diverting neutral current through the shunt field
Description : What happens to the permeability of an iron core as the current increases from the operating point to a large value?
Last Answer : Permeability decreases
Description : A low voltage source is being used for testing armature coils. A coil short circuit will be indicated by a _______. A. high voltage reading, while the other coil readings will have an ... the other coil readings are steady D. steady voltmeter reading, while the other coil readings are fluctuating
Description : Ratio of voltages is equal to ratio of A. iron sheets in core B. coil C. number of turns in coil D. all of above
Last Answer : number of turns in coil
Description : Two circular coils 1 and 2 are made from the same wire but the radius of the 1st coil is twice that of the 2nd coil. What is the ratio of potentail di
Last Answer : Two circular coils 1 and 2 are made from the same wire but the radius of the 1st coil is twice that of the 2nd coil ... the same? A. 3 B. 4 C. 6 D. 2
Description : The distance between the starts of two consecutive coils measured in terms of coil sides is called (a) front pitch (b) winding pitch (c) commutator pitch (d) back pitch
Last Answer : (b) winding pitch
Description : The coefficient of coupling between two coils is 0.45. The first coil has an inductance of 75 mH and the second coil has an inductance of 105 mH. What is the mutual inductance between the coils? (1) 3.54 mH (2) 7.88 mH (3) 39.9 mH (4) 189.3 mH
Last Answer : The coefficient of coupling between two coils is 0.45. The first coil has an inductance of 75 mH and the second coil has an inductance of 105 mH. 39.9 mH is the mutual inductance between the coils.
Description : An AC circuit consists of a resistance and a choke coil in series . The resistance is of 220 `Omega` and choke coils is of 0.7 H . The power abosorbed
Last Answer : An AC circuit consists of a resistance and a choke coil in series . The resistance is of 220 ` ... 50 Hz , source connected with the circuit , is
Description : Air gap readings should be taken periodicly on electrical generation equipment to __________. A. determine the amount of varnish that can be applied to correct insulation problems B. determine the ... field coil bolts and correct lateral adjustment of the field coils D. increase machine efficiency
Description : When troubleshooting motor controllers, a shorted relay or contactor coil is often indicated by _______________. A. a resistance reading of 'infinity' on an ohmmeter B. charred insulation and/or a blown ... of the coil's leads to ground D. a higher-than-normal voltage reading across the winding
Description : Excessive humming of AC contactors may be caused by ______________. A. burnt arc shields B. shorted armature coils C. a broken shading coil D. high voltage
Description : If coil 'R1-R2' on the transmitter in figure 'A' shown in the illustration is turned 30 degrees clockwise, corresponding coil 'R1-R2' on the receiver should ____________. EL-0092 A. make coils 'S1 ... a higher voltage depending on the turns ratio D. align itself to the same position if free to move
Description : The maximum shear stress in spring wire is induced at (A) Inner surface of the coil (B) Outer surface of the coil (C) Central surface of the coil (D) End coils
Last Answer : (A) Inner surface of the coil
Description : If uncompressed length of spring is 40mm and number of coils 10mm, then pitch of coil is? a) 4 b) 40/9 c) 40/11 d) None of the mentioned
Last Answer : b) 40/9
Description : DC relay coil or contactor coils must be connected to which side?
Last Answer : Negative side of the DC supply to avoid galvanic effect on the coil, which will corrode the coil.
Description : A close coil helical spring of mean diameter D consists of n coils of diameter d. If it carries an axial load W, the energy stored in the spring, is (A) 4WD²n/d 4N (B) 4W²Dn/d 4N (C) 4W²D3n/d 4N (D) 4W²D3n²/d 4N
Last Answer : (C) 4W²D3n/d 4N
Description : A close coil helical spring when subjected to a moment M having its axis along the axis of the helix (A) It is subjected to pure bending (B) Its mean diameter will decrease (C) Its number of coils will increase (D) All the above
Last Answer : (A) It is subjected to pure bending
Description : The windings of the electromagnetic are usually called: a. Magnetic coils b. Field coil c. Electric coil d. simple coil
Last Answer : c. Electric coil
Description : A compression spring is made of music wire of 2 mm diameter having a shear strength and shear modulus of 800 Mpa and 80 Gpa respectively. The mean coil diameter is 20mm, free length is 40 mm, and the number ... by 8 times b. decreased by 2 times c. increased by 2 times d. decreased by 8 times
Last Answer : a. increased by 8 times
Description : The coefficient of coupling between two air core coils depends on (A) mutual inductance between two coils only (B) self inductances of the two coils only (C) mutual inductance and self inductances of the two coils (D) none
Last Answer : The coefficient of coupling between two air core coils depends on mutual inductance and self inductances of the two coils
Description : In D.C. motor construction, the armature coils' ends are _______________. A. soldered to the commutator bar risers B. imbedded into core slots C. crimped together with brush pigtails D. spliced with the field windings
Description : Pick up the correct statement from the following: (A) A wire wound in spiral form, is called a helical spring (B) The pitch of a close coil spring, is very small (C) The angle made by the coil with horizontal, is called the angle of helix (D) All the above
Last Answer : (D) All the above
Description : Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation
Description : Do small core distortions formed by arc fusion's self alignment mechanism have more of an affect on light propagating through multimode or single mode fibers?
Last Answer : Single mode fibers.
Description : In single mode operation, the value of the normalized frequency (V) should remain near the 2.405 level. If the value of V is less than 1, do single mode fibers carry a majority of the power in the core or cladding material?
Last Answer : Cladding material.
Description : List the standard core sizes for multimode step-index, multimode graded-index, and single mode fibers
Last Answer : Multimode step-index fibers: 50µm and 100µm. Multimode graded-index fibers: 50µm, 62.5µm, 85µm, and 100µm. Single mode fibers: between 8µm and 10µm.
Description : Explain the difference between multimode and single mode core-cladding concentricity errors.
Last Answer : Multimode core-cladding concentricity error is the distance between the core and cladding centers expressed as a percentage of core diameter while the single mode core-cladding concentricity error is just the distance between the core and cladding centers
Description : A mode filter is a device that attenuates specific modes propagating in the core of an optical fiber. What mode propagating along single mode fibers do mode filters eliminate?
Last Answer : Second-order mode.
Description : The value of the normalized frequency parameter (V) relates the core size with mode propagation. When single mode fibers propagate only the fundamental mode, what is the value of V?
Last Answer : V≤2.405.
Description : Which of the two types of deflection coils (fixed or rotating) is used most often?
Last Answer : Fixed.
Description : What is the effect of current flow through the coil in a d’Arsonval meter movement?
Last Answer : A magnetic field is generated around the coil and the attraction of this field with the permanent magnet causes the coil to move
Description : (True or False) The larger the current required to produce full-scale deflection of the meter coil, the better the sensitivity of the meter.
Last Answer : False.
Description : What component of the D’Arsonval meter movement completes the circuit for current flow to the coil?
Last Answer : Hairspring.
Description : In D.C. motor construction, commutating windings are wound on _________________. A. opposite main poles B. interpoles C. adjacent main poles D. the rotor core
Description : In the construction of D.C. motors, parts of both the series and shunt fields are wound on the _____________. A. opposite main pole B. rotor core C. interpole D. same main pole
Description : Please ripley me due to emergency
Last Answer : To calculate the flux density in the ring, you need to use the following formula: B = (μ * I * N) / (2 * π * r) where: B is the flux density in the ring (in teslas) μ is the relative permeability ... 2 * π * 0.127 m) = 0.53 T So the flux density in the ring would be approximately 0.53 teslas.
Description : Which type of AC single-phase motor will also operate on direct current? A. Split-phase B. Series-wound C. Shaded-pole D. Repulsion-start
Description : How is the disadvantage of the Gramme-ring armature overcome in the drum-wound armature?
Last Answer : By winding the armature in a way that places the entire coil where it is exposed to maximum flux.
Description : The refractive index of a fiber core is uniform and undergoes an abrupt change at the corecladding boundary. Is this fiber a step-index or graded-index fiber?
Last Answer : graded-index fiber?