llow is a uuuus motor started and brought up to closu lu sya sperr a) By counpuu

Question

llow is a uuuus motor started and brought up to closu lu sya sperr a) By counpuusaling windings, kuo as starting wiudiuus wil h) y employing srarting eapacitors r) lly squirrel race induction winding, also called the augrtixtur winding d) By the use nfimtomolwa also relented to as comumutalius pulus 0) A rylindrical rotor symchronous tuekou dead. If the maxiu it can prodimme with the given exciratinn is 220 nf d torque the strated lo d tdeal rior r resistance forthe forward aud zevetve current Elows are respectively Zero 2nd irtinitely ler ZNo in hnth directions lafizitely large in botu di cari cins

Explanation / Answer

question 1:

The answer is a

The motor is started using starting winding also called as damper winding or compensated winding.

Modern synchronous machines are usually are of self starting type and are arranged to stat as induction motors. The synchronous motor is made self starting winding by providing damper windings or squirrel cage winding in the rotor poles. In the faces of the field poles damper windings are provided. Damper windings are the short circuited copper bars inserted in pole faces of field poles. 3-phase AC supply provided to stator windings of the synchronous motor generates a rotating magnetic field which rotates at synchronous speeds. This rotating magnetic field cuts the damper windings in the rotor. An emf is induced in the damper windings and current flows through the damper windings. This damper winding current produces a magnetic field which on interaction with the rotating magnetic field generates a torque which helps to rotate the synchronous motor as induction motor during stating. When the motor attains a speed of about 95% of the synchronous speed, the rotor windings are connected to the exciter terminals which locks the rotating field of the stator and rotating rotor of synchronous motor.

question 2:

The point of maximum torque occurs at a power angle of approximately 90 for a cylindrical-rotor machine. This maximum value of torque that causes a synchronous motor to pull out of synchronism is called the pull-out torque. In actual practice, the motor will never be operated at power angles close to 90 as armature current will be many times its rated value at this load.

question 3:

In an ideal diode the forward resistance is zero and reverse bias resistance is infinitely high

Related Questions

Navigate

• Browse (All)
• Browse L
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.