Answer / 7anoter4

The a.c. electricity is produced in an a.c. generator which transform mechanical energy [from a turbine or diesel motor or else] into electrical energy.
In a synchronous generator the rotor produce a magnetic field -as permanent magnet or from d.c. current flowing through wired bobbins.
Let's take a single loop of the stator coil and expose it to a rotating magnetic field.
The EMF [electromotive force=induced voltage in the loop] =E=-dΦ/dt where:
Φ=magnetic flux through one stator [armature] loop
E=Electromotive Force [induced voltage]
Since the armature [stator] loop does not move then the magnetic flux shared with the loop is changing with the angle between loop surface and rotor pole surface. Φ=BxAxcos(α).where:
B =magnetic flux density produced from magnetic pole
A=magnetic pole area
rpm=no.of rotations per minute
Finally, E=BxAxsin(ωxt) where ω=2xπxpxRPM/60 p=no.of pole pairs t=time
That means the produced voltage depends on sinus of time.

in our 6.6kv motor feeder[it is having two sources from Bus A&B] earth fault relay is acting, we checked CBCT connection and cable meggerd values found very good still earth fault acting during first two are three start after that it will hold. please clarify what was the reason. if same motor is starting from other Bus-A it will start.

1 Answers   Gasal, Voltech,

---

What is the difference between hot and cold loop testing?

0 Answers  

---

why solinoid coil used in tripping rely?and why not other type coil?

1 Answers  

---

What is the maxvoltage drop allowed at any healthy joint at full load ?

1 Answers   Kirloskar, Seyadu,

---

what is the calculation of current when a clampmeter is attached to two phases of any drives.

3 Answers   ABB,

---

Can we use a window type neutral CT instead of a bar type neutral CT. We have an issue with a neutral bar type CT of 800/1 ratio with a Circuit breaker NS800L shneider type, and we want to change it with a window type. Pls advise. Thanks

1 Answers  

---

What should be the setting of an earth fault relay.

2 Answers   HP,

---

Give the topology of current amplifier with current shunt feedback?

0 Answers  

---

What is the reasonable voltage between Neutral & Earth of an electrical system for good earthing?

6 Answers   HAL,

---

what is exact meaning of CT core saturation or simply saturation of core.

1 Answers  

---

in Telecom DC system-why positive +ve is made earthed.and - ve is fed to load.

0 Answers  

---

Which power will flow first if we switch on a motor Active or Reactive? How?

3 Answers  

---