I am installing an electronic trip unit on a 480 volt Circuit Breaker that is protecting a 240 KVAR capacitor bank. The cap bank is made up of 12 modules. Each 20KVAR module consists of 3 delta connected capacitors (each cap is 6.66 KVAR). The substation is a typical 1500KVA solidly grounded...
How long do you need to wait to restart an induction motor that is still coasting? I have a 1000HP 4160V motor for a large blower that will coast for 10+ minutes after it is shutdown. In this case, if the motor is off for more than 5 minutes the plant must go through a very lengthy startup...
A 750KW, 4000V European motor at my plantsite in the US lists three parameters that I am not familiar with and I have not been able to find a reference on:
Ma/Mn = .7
Ia/In = 5.3
Te = 16s
The Ia/In looks like the ratio of locked rotor current to full load current (maybe Iaccel./Inormal) but I...
Is it possible to draw greater than LRA on starting due to a voltage unbalance caused by a bad connection?
This weekend a 1000HP 4160volt motor with a normal 12 second acceleration time tripped two of its 3 mechanical overloads in 5 seconds during a start. The installation was checked and a...
About a month ago I replaced an old 2300 volt oil immersed motor starter lineup with new vacuum contactor starters. One of the motors has since failed to ground and I was wondering if the failure could have occurred because of a transient caused by the fast interrupting time of the vacuum...
I am looking for some advice or a reference on how to size a Core Balance CT for differential protection for a 2500HP 6900 volt motor. The motor is 190 FLA. I have been told I should use a 300:5 CT by one person and 50:5 by another. The system is high resistance grounded.
I am an Electrical Engineer looking for some information on the advantages and disadvantages of the different types of silicon bronze alloys for joining bus bars together.
I know that Silicon bronze is a general term that describes various types of copper-silicon alloys manufactured under...
Does anybody have any experiance in selecting between the different types of silicon bronze hardware for joining busbars?
I know that Silicon bronze is a general term that describes various types of copper-silicon alloys manufactured under trade names such as Everdur, Herculoy, Duronze."
The...
What is the purpose of a volts squared hours meter? My utility company has one installed on my purchased power substation but I can't find anyone who knows what it is for.
