Which other PSU's conduct their own exams apart from gate?* and how do we find their notifications...

ONGC, ISRO, BARC, DRDO . These are some psu, please check their website notifiications.

Hello,
PSU Which Conduct Own Exam:

• S.No.
• PSUs
• Branches
• Eligible
• Age
• Exam
• Pattern
• GEN
• OBC
• SC/ST

1
CIL
CE, ME, EE, ECE
30
33
35
Written Test + PI
2
SAIL
ME, EE, ECE, IN, CS
30
33
35
Written Test +PI
3
ISRO
CE, ME, EE, CS, ECE
35
38
40
Written Test + PI
4
DRDO
CE, EE, ME, ECE, CS
28
31
33
Written Test/GATE + PI
5
VIZAG
CE, ME, CS & IT, CH, IN, EE
27
30
32
Written Test + GD/PI
6
BEL
CE, ME, EE, ECE, CS
25
28
30
Written Test + PI
7
EIL
CE, ME
25
28
30
Written Test + PI
8
BARC
CE, ME, EE, ECE, IN
26
29
31
Written Test + PI
You can go through the below given link for more details:
http://www.engineersacademy.org/course_content.php?course=psu&slug=psu-which-conduct-own-exam
Good luck.