Answer / tpfasil200

Direction of rotation of synchronous motor is determined b y its starting direction,as initiated by inducyion motor action. Thus, to reverse the direction of a 3 phase synchronous motor, it is necessary to first stop the motor and then reverse the phase sequence of the 3 phase connections at the stator. REVERSING THE CURRENT TO FIELD WINDINGS WILL NOT AFFECT THE DIRECTION OF ROTATION

Answer / tpfasil200

Direction of rotation of dc motor can be reversed in 2 ways
1.reversing current through armature and interpole windings(if they exist)
2.reversing current through field windings,ie,through shunt and/or series winding..but not through interpole windings(if they exist)
Reversing current through the armature is preferred because reversing current through the field windings involves breaking and making highly inductive currents of the field windings.Also field reversal of compound motors requires connections of both shunt and series windings to be changed..

Answer / prasanth

1.in alternator the induced emf is reduced due to retentive property of the field magnet when reversed.

what is priming pump?why it is used ?

2 Answers  

---

Differcence between UPS and Inverter.

4 Answers   Adani,

---

What is the function of NGR for the parallel operation of alternator? whats happen when different rating of alternator are running with parallel?

0 Answers   Welspun,

---

There is no such thing as a Generator. All power generating devices are Alternator since both generate alternating current since this is the only way electrical power can be generated. In "generators" the alternating current is converted into DC inside the housing of the "generator" in order to give out DC Do you agree? If not please educate me. How else is DC generated if not like above?

2 Answers  

---

What is distance protection relay? where & why we use this relay?

2 Answers   Siemens, UltraTech, Voltech,

---

instead of neutral can we use earth/ground to flow the current in the circuit

2 Answers   Infosys,

---

What is the formula to calculate a three phase alternator

0 Answers  

---

what are smoke detectors ?

4 Answers   Indian Military Services,

---

with help of neat sketch explain principle of TIG welding process

0 Answers  

---

I want single line diagram for AMF & DG syncronizing panel

0 Answers  

---

If a transformer primary winding operates at 240v, the secondary at 120v and the load is 1500w & the transformer is rated at 92% efficient, what's the current flowing through the primary winding of the transformer? What is the formula for finding this?

0 Answers  

---

back emf of motor at the time of starting ?

2 Answers  

---