Goals and By GV2 - is motor 100 % protected against phase failure ? According catalogue - IEC Symptoms 947- 4-1 (paragraph 7-2-1-5-2) , in the case 2 phase operation tripping have to be
Facts Changes
Causes Fixes
during 2 hours.
But during this time and 2 phase operation motor will burn. What do you think ?
Is it enough to protect by GV2 or it is necessary to use relays for detection phase loss ?
We already had some cases,when m.c.breaker did not trip and in this case protected motor is expensive - his price 60 times of price GV2. Thank you
and GV2 - protection against Phase failure and The GV2 is conform to the IEC947 standard for the motor protection.
In case of phase lost the GV2 must trip before 2 hours according to the IEC947 conditions : 1,15 Ir in two phases and no current in the 3rd .
The motor can not burn is such conditions . However if the current in the 2 phases is higher than 1,15 Ir the GV2 will trip on thermal defect . So : the GV2 is enougth to protect the motor .
Note : in case of hoisting application, for security, it is usufull to add a phase lost protection relay ( phase lost = often : load lost and for hoisting: load lost )
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