Delta NT Series - Chapter 8: Optional Accessories; Input Harmonic Filter

Chapter 8 Optional Accessories
100
Chapter 8 : Optional Accessories
 SXOVH5HFWL¿HU
7RUHGXFHLQSXWFXUUHQWKDUPRQLFGLVWRUWLRQWKHLQVWDOODWLRQRIDSOXVHUHFWL¿HULV
suggested.
The 12-pluse rectifier is composed of one transformer and two rectifiers. After
receiving the AC input power, the transformer will (1) transfer the input voltage into
WZRGLႇHUHQWYROWDJHSRZHUVRXUFHVZLWK
o
SKDVHGLႇHUHQFHDQGVHQGWKHWZR
SRZHUVRXUFHVWRWKHWZRUHFWLILHUVZKLFKFDQUHGXFHWKHLQSXWVLGH¶V
th
and 7
th
LQSXWFXUUHQWKDUPRQLFGLVWRUWLRQLQRUGHUWRPHHWWKHUHTXLUHPHQWRIUHGXFLQJWKH
total input current harmonic distortion considerably.
In general, the total input current harmonic distortion is about 32~38% with use
RIDSOXVHUHFWL¿HUEXWWKHSOXVHUHFWL¿HUFRXOGUHGXFHWKHWRWDOLQSXWFXUUHQW
harmonic distortion to 10~18%.
7KHSXOVHUHFWL¿HU¶VVWUXFWXUHGLDJUDPLVVKRZQLQFigure 8-1.
)LJXUHSXOVH5HFWL¿HU¶V6WUXFWXUH'LDJUDP
Y
RECT 1
RECT 2
DC BUS
AC INPUT
8.2 Input Harmonic Filter
Besides the 12-pluse rectifier, the passive-type input harmonic filter (L-C filter) is
another solution to reducing the total input current harmonic distortion. Moreover, it
is also a means to improve the input power factor of the UPS.
)RUWKH836WKDWLVLQVWDOOHGWKHSOXVHUHFWL¿HUWKHLQVWDOODWLRQRIWKH
th
passive-
W\SHLQSXWKDUPRQLF¿OWHU/&¿OWHULVVXJJHVWHG