We had recently a blackout due to a Buchholz trip of a 132/6,3kV YNyn 18,75MVA due to a downstream phase to phase short-circuit.
I knew that occasionally Buchholz trip might be faster than phase protection relays; but only in case of an internal fault. In this case, there are 3 phase protection...
I will be probably late, but here I go with my advice.
I think the insulation resistance drop might indicate some kind of incipient damage. While you are testing insulation resistance, the HV isolation of the xformer acts like a big condenser charging, so, the more time you apply Vcd, the...
Jurriaan, did you set P0971=1 after the converter commisioning?
How did you carry out the converter commisioning? I had similar trouble using the STARTER software. Try to use DriveMonitor or set the parameters one by one with the BOP.
Synchronous motor 3800hp 6300V 259A 50hz 250rpm P.F.=1 brushless type. Exciter field=7.1Amps Exciter output =144.5V 135Amps. 2 different controlled rectifier bridges (for auto/hand PF control mode) feeding the exciter field.
The motor load is a reciprocating compressor. Suction and...
The upper bearing cap pressed outer ring. It was necesary to turn on the lathe and mechanize 0,2 mm.
As said before, the rotor could be moved by hand, and I supposed the very little resistance was because of the grease retainers...
Again, the right was the most simple explanation; but even now...
First of all, thank you for your appreciable help.
Jraef,
there is no mismatch possible in the motor connection, because the star is internal and only three terminals are available for 380V connection. 380 Volts remains stable, even with the motor running.
Waross,
when opened the motor for...
As well as for equipotentiality of all conductive surfaces, you also have to assure a proper path to the current in the event of an earth fault.
If the motor frame is already earthed properly by means of a earth wire with the right section you can only bring three conductors to the motor.
The trouble is on a Pennwalt rotating Vibro-screen with direct on-line 1,5Hp 380V 2,3Amps 50Hz 720rpm induction motor (no frequency converter).
http://files.engineering.com/getfile.aspx?folder=e712cc45-a251-4944-9baa-5f4252355198&file=R-00814_209703____1.1.pdf
The screen was working properly...
Maybe the problem is the vacuum contactor and capacitor bank combination. Because of the short interrupting time of vaccum switches/contactors, they can induce overvoltages (current chopping phenomenon), and the capacitors might amplify these overvoltages. Surge arresters are recommended(See...
