FredG said:
Hello,
Thanks for your explanation. It's a very good synthesis. Therefore, I have 3 questions.
Firstly, you mentionned you're trying to use fuses only with small loads because the protection of phase missing is not assured by the standard fuses. But Schneider sales engineer mentionned me we can use an electronic equipment (fuse monitor) to detect the phase failure. Is it expensive? Did you already used?
Secondly, you mentionned also problem to have fuses above 630A. Do fuse manufacturers range limit their range at 630A? Which manufacturers can I choose?
And Finally, why do you prefer to use fuses to protect capacitors? I have some applications where I have to protect capacitors. So, I'm very interesting to have your position.
Another question, I've also some customers who are using Drives. I was thinking to use fuse UR for these appplications. What is your position on this topic?Best regards,
FredG
Dear ;
1 – About ” Fuse Monitor ” from Schneider : till now I don't use it, because it's expensive more than ” Fuse with Striker + Fuse Holder with Auxiliary Contact “.
2 – ” NH fuses” ” more than ” 630A ” : as most of manufactures limit their rang ” up to 630A ” but some of them like ” Ferraz Shawmut ” produces NH Fuses ” up to 1250 A “.
3 – About the protection for ” 3 Ph-LV Capacitors ” : I use the Fuses to protect these Capacitors for the following reason :
A – No need of ” missing phase protection ” for Capacitors.
B – These Capacitors are composed from ” 3 Single Phase Capacitors “, and there's no a big problem if one of them will be disconnected
due to a fuse blown.
C – About the external body :
1 – If it's made from ” Insulation Material “, the possibility to have and Earth Fault is too limited.
2 – If it's made from ” Conductive Material “, and as the installation's places of Capacitors are either near the Main Distribution
Board or near the Sub-Main Distribution Boards where the value of the Earth Fault is enough to blow the fuse due an Earth Fault.
4 – About the protection of the Drives : as the values of the fault currents in the Drives are limited, and most of Drives have inside ( by programming ) the phase missing protection, we can use the UR fuses.