Answer / john bosco

knee point voltage definition
when applying voltage in secondary gradually from zero
and measuring current for step voltages, the current raise maintains constant slope up to some level of voltage.
for further raise in voltage secondary current raise do not follow the slope.
the voltage from which 10 % raise gives 50% raise in secondary current called as knee point voltage of current transformer(IEC standard)

saturation voltage is maximum secondary voltage developed across ct for any primary current

protection class CT
formula for VK= Is.ALF.(Rct+Rb)
Is- rated secondary current
ALF- accuracy limit factor
Rct- measured secondary resistance
Rb - rated burden of CT

Answer / thowsif_emerson_csm team

The knee point
is a ten percent ratio error between the
primary input current and the corresponding secondary
output current.

The saturation point involves determining the secondary
voltage necessary to drive the measured current through the
impedance of the secondary circuit.

For More Details,Pls visit
http://www.control.com/thread/1026243854

why mccb is not tripping when phase & neutral terminal are interched ?

4 Answers  

---

why the rotor current becomes in steady state during high slip region? please verify with equations.

0 Answers  

---

How much load can give on 1600 kva transformer 11kv/440

5 Answers  

---

Upto what extend the powerfactor of a supply system can be improved to be cost effective?

1 Answers  

---

HOW CAN YOU CALCULATE PRACTICAL EFFICIENCY OF A ASYNCHRONOUS INDUCTIONMOTOR OF 7.5KW,& MOTOR IS RUNNING WITH AVOLTAGE OF 410 VOLTS,& TAKING CURENT OF 13 AMPS

0 Answers  

---

How can we calculate the KVA rating of a Distribution transformer from its core details?

0 Answers   ABB,

---

In dc motor starter there is less voltage required for holding contactor that's may why it is called no volt coil. but in ac starter why holding contactor is called no volt coil.

2 Answers   JSW,

---

how freewheeling diode improves the powerfactor

0 Answers  

---

what is the earth current,reverse power,electrical trip generator short circuit,low voltage, high voltage please discribe me

0 Answers  

---

Definition of grid?

7 Answers   L&T, Pace Power Systems, Vijai Electricals,

---

Explain thin film resistors and wire-wound resistors

0 Answers  

---

What is meant by locking of rotor in synchronous motor? Explain me locking in detail?

3 Answers  

---