Inovance MD320 Series, User Manual

Page: 158 / 202

EMC Guide MD320/MD320N User Manual
3)
7KH VXUURXQGLQJ HTXLSPHQW LV VHSDUDWHO\ HDUWKHG ZKLFK FDQ DYRLG WKH LQWHUIHUHQFH
caused by the leakage current of the inverter’s earth wire when common earth mode is
adopted.
7.3.5 Leakage current and handling
There are two forms of leakage current when using the inverter. One is leakage current to the
HDUWKDQGWKHRWKHULVOHDNDJHFXUUHQWEHWZHHQWKHFDEOHV
1)
)DFWRUVLQÀXHQFLQJWKHOHDNDJHFXUUHQWWRWKHHDUWKDQGWKHVROXWLRQV
There are distributed capacitance between the lead cables and the earth. The larger the
GLVWULEXWHGFDSDFLWDQFHLVWKHODUJHUWKHOHDNDJHFXUUHQWZLOOEH7KHGLVWULEXWHGFDSDFLWDQFH
can be reduced by effectively reducing the distance between the inverter and the motor. The
KLJKHUWKHFDUULHUIUHTXHQF\LVWKHODUJHUWKHOHDNDJHFXUUHQWZLOOEH7KHOHDNDJHFXUUHQWFDQ
EHUHGXFHGE\UHGXFLQJWKHFDUULHUIURZHYHUUHGXFLQJWKHFDUULHUIUHTXHQF\PD\
result in addition of motor noise. Note that additional installation of reactor is also an effective
method to remove the leakage current.
7KHOHDNDJHFXUUHQWPD\LQFUHDVHIROORZLQJWKHDGGLWLRQRIFLUFXLWFXUUHQW7KHUHIRUHZKHQWKH
PRWRUSRZHULVKLJKWKHFRUUHVSRQGLQJOHDNDJHFXUUHQWZLOOEHKLJKWRR
2) Factors of producing leakage current between the cables and solutions:
There is distributed capacitance between the output cables of the inverter. If the current passing
WKHOLQHVKDVKLJKHUKDUPRQLFLWPD\FDXVHUHVRQDQFHDQGWKXVUHVXOWLQOHDNDJHFXUUHQW,I
WKHUPDOUHOD\LVXVHGLWPD\JHQHUDWHHUURUDFWLRQ
The solution is to reduce the carrier frequency or install output reactor. It is recommended that
WKHUPDOUHOD\QRWEHLQVWDOOHGEHIRUHWKHPRWRUZKHQXVLQJWKHLQYHUWHUDQGWKDWHOHFWURQLFRYHU
current protection function of the inverter be used instead.
7.3.6 Precautions for Installing EMC input ¿ lter at the input end of power supply
1)
:KHQXVLQJWKHLQYHUWHUSOHDVHIROORZLWVUDWHGYDOXHVVWULFWO\6LQFHWKH¿OWHUEHORQJVWR
&ODVVL¿FDWLRQ,HOHFWULFDSSOLDQFHVWKHPHWDOHQFORVXUHRIWKH¿OWHUVKDOOEHODUJHDQGWKH
metal ground of the installing cabinet shall be well earthed and have good conduction
continuity. Otherwise there may be danger of electric shock and the EMC effect may be
greatly affected.
2)
7KURXJKWKH(0&WHVWLWLVIRXQGWKDWWKH¿OWHUJURXQGPXVWEHFRQQHFWHGZLWKWKH3(HQG
of the inverter at the same public earth. Otherwise the EMC effect may be greatly affected.
3)
7KH¿OWHUVKDOOEHLQVWDOOHGDWDSODFHFORVHWRWKHLQSXWHQGRIWKHSRZHUVXSSO\DVPXFK
as possible.
efesotomasyon.com