Question 146Electricity/Electronics - QMED70% to pass
A digital multimeter is set up as shown in the illustration to evaluate the single-circuit stator windings of a squirrel cage induction three-phase motor. The following readings are taken: From T1 to T2 reads "OL" ohms. From T2 to T3 reads "OL" ohms. From T3 to T1 as shown reads "1.6" ohms. What condition is indicated? Illustration EL-0219
AI Explanation
The correct answer is A) Phase A (associated with T1) are short-circuited.
The reasoning is as follows:
1) The readings show that the resistance between T1-T2 and T2-T3 are both "OL" (open-loop), indicating an open circuit in those phases.
2) However, the reading between T3-T1 is 1.6 ohms, which suggests a short circuit in that phase (Phase A associated with T1).
3) The other options are incorrect because they do not accurately describe the condition indicated by the readings.
4) In summary, the multimeter readings indicate a short circuit in Phase A of the three-phase motor's stator windings.
Related Questions
#144 If the centrifugal switch or relay used for cutting out the starting winding of a split- phase induction motor fails to open once the motor is in operation, what will be the result? #145 A single-phase capacitor-start induction motor starts, comes up to about 75% rated speed, slows down to a lower speed, and accelerates again. Where is the problem most likely to be? #147 By what means is the burning of controller contacts due to arcing, when opening, prevented? #148 As shown in figure "B" of the illustration, when the DC motor in figure "A" is operating at minimum speed what are the armature and field characteristics? Illustration EL-0153 #149 As shown in the illustrated electrically operated watertight door controller, how is the rotation direction of the door motor reversed? Illustration EL-0115