Yes.
Nothing.............Just do as shown in above post.
Test diodes same way as in diode bridge, each diode separately.
I think that NLU part can not be tested separately,
It is only possible to compare conductivity between gate terminal and the corresponding emitter
in each IGBT.
Test with multimeter diode-range in both polarity by changing meter wires ( same as in diode test )
Values should be same with each IGBT-gate.
In attached picture in...........
https://www.edaboard.com/threads/227364/#post969472
has simple explanation of NLU principle .
KAK
thanks a lot .......
1) so there are total 13 diodes , so test all of the 13 diodes separately both in reverse bias & forward bias condition ? am i right ???
For testing IGBTs having Gates : Gb (7), Gx (8) , Gy (9) & Gz (10) the Emitter is same i.e. E (11), Am i right ??? Can't we take "N" as Emitter because they both shorted out to each other ( for testing the IGBTs whose Gate's names are mentioned above ) ????
2) For testing IGBTs having Gates : Gu (1), Gv (3) , Gw (5) the Collector is same i.e. P1 , Am i right ???
3) And taking Emitters Eu (2) for IGBT whose gate is Gu (1), Ev (4) for IGBT whose gate is Gv (3) ,
Ew (6) for IGBT whose gate is Gw (5) ... Am i right , sir ???
4) Can't we take U as emitter of the IGBT whose gate is Gu (1) instead of Eu (2) ?
Similarly, Can't we take V as emitter of the IGBT whose gate is Gv (3) instead of Ev (4) ?
And, Similarly, Can't we take W as emitter of the IGBT whose gate is Gw (5) instead of Ew (6) ?
Cause U is shorted out to Eu (2)
Similarly, V is shorted out to Ev (4)
And, W is shorted out to Ew (6) .....
5) For Testing diodes individually :
a) For Converter Circuit (the diodes on the above) : cathode is P & Anode is R, S & T. Am i right ?
b) For Converter Circuit (the diodes on the bottom) : cathode is R, S & T & Anode is N or E (11). Am i right ?
c) For Brake Circuit : cathode is P1 & Anode is B. Am i right ?
d) For Inverter Circuit (the diodes on the above) : cathode is P1 & Anode is Eu, Ev & Ew OR (U, V & W Respectively). Am i right ?
e) For Inverter Circuit (the diodes on the bottom) : cathode is U, V & W & Anode is N or E (11). Am i right ?
Kindly, answer these thanks a lot