Answer / kj

See extract from service manual for HV alternator.

A 5000V motorised megger or similar instrument should be
used. Separate the three neutral leads,
ground V and W leads and megger U to ground. Repeat for V
phase with U and W grounded and W
phase with U and V grounded. Minimum acceptable limits
after 1 minute for each phase are:
New machine 300 M

In-service machine 150 M

The insulation resistance should not be less than specified
and the polarisation index should be in the
order of 2 or greater at 20 ºC.
(PI = IR10min / IR1min)

what does the word synchronous mean in 'synchronous machine'

3 Answers  

---

Why neutral has to switch on-off with phase in TN IT TT systems i.e neutral should be taken as fourth pole

1 Answers  

---

what is the difference b/w ATS and HTS?

0 Answers   Mikano,

---

what is buchholz relay?what is it used for?

8 Answers   Engineers India Limited, NFCL,

---

How to do bus bar short circuit calculation for 230KV/11kv, 60 MVA Substation?

0 Answers   ABB,

---

explain PV modules in solar energy generation.

0 Answers  

---

what is the purpose of the armored for the power Or control cable? How to select the type of the armored?

1 Answers   Siemens,

---

what is the different between RCCB & ELCB

3 Answers  

---

what are the accessories need to be added while doing estimation for the following: 1.MCCB 2.MCB 3.ACB

0 Answers  

---

sir i had plane to do some project with the base of hopkinson test in AC supply its possible

0 Answers  

---

are you hear the meaning of burden , excat meaning of burden in only one word

4 Answers  

---

if u want to buy a motor than what will be the configuration of that motor?

2 Answers  

---