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What happens if you try to use a 500 hp motor, rated at 440 V , with a 6-pulse drive, rated at 600 A?

This is an unusual question: from sometime now, I'M having difficulties with Doble and the DTA module. When entering some values (KVA rating, Voltages, Test kV, etc), I can't use commas, or dots to specify decimals. Example: I have a 13,2 kV primary voltage, but I cannot enter 13,2 or 13.2...

For years I have meggered all transformers at 1000 Vdc for 1 minute. From 600 V thru 120 kV, dry type or oil liquid filled, 1000 V is the voltage, in our maintenance procedure. Now this morning I learn that higher voltages can/must be used. Was I wrong for all these years?

Hi all. We have a situation where a Y-Y 2500 KVA transformer gives weird voltage readings on the secondary side. Just after the first energization, we take voltage readings, without any load connected. All phase to phase voltages are OK at approx 600 V. But we have A-N =347 V , B-N = 320 V and...

We have some transformers filled with FR3 liquid that we test annually. Problem is, with the aging of the units, the megger values are decreasing and the Doble results are getting worse. DGA doesn't show anything suspect, except that somewhat hi level of ethane (C2H6). These units are on...

I have a consultant asking for this. He has an application (ozonation process in water treatment plant) that is fed by a PWM source. He's using a Schneider type LR9F5569 class 20 O/L that trips the moment power is applied on the ozonation equipment. Any suggestion?

Hello all, I'm looking for informations about this breaker and the trip unit that was installed on. The trip unit I have is a Statipac 100, and Googling this has not been successful. Any help is welcome. thanks Bob

After all, it is a dc vehicle, no?

Hi all, I have a situation where low voltage cables are becoming hot, about 60 C at the hottest point in the gear B phase (middle). Customer wants to know if this is normal. Here's the scenario: We have to feed a 3000 A gear. We have 600V 750 MCM Nual ACWU90 single conductor armored cable...

Good Day. Looking for manuals for the above relay – specifically the explanation of settings and time-curve curves. Thanks!http://files.engineering.com/getfile.aspx?folder=cf5b152d-14cc-4e17-bd0d-5317533aad4e&file=CTM44.pdf

Hi all! I'm having a discussion with a consultant about the caliber to use for the primary side of a 5000 kva transformer. I'm using the nominal current to size my fuse. Primary is 25 kV so the nominal current is about 116 A. I'm going with a 150E SM-5 S&C fuse. The consultant wants to use a...

Good paper on VLF.

Hi all! Please refer to the attachment. This is a 6600 V switchgear, built in the 40's. In it, there are neon ground lamps witch appears to be inductively coupled to the bars. We're wandering what this capacitor-like symbol represents? It is not possible for us to inspect these devices without...

Hi all! In a 5 kV switchgear, would a busbar differential protection help reducing the Arc Flash Hazard? I think yes. Your comments are welcome.

Does anybody here uses this when testing transformers? I have read alot on this subject and found it very interesting. I included a document for those of you who are curious... Any comments are welcome.

Hello all! I looking for an instruction manual for this drive. Does anyone here have one? Thanks for your help.

Hi all! I have to download data into an electronic temperature controler. Its for a 5 MVA dry-type transformer. I need to program fan, alarm and trip temperatures and to make the controler non-failsafe. So I installed the software on my Lap-top and tried communicating. It failed. The Com...

Do these relays do the same thing? SEL literature describes Device Number 67 as Negative-Sequence Relay and ANSI as AC Directional OC Relay. One Hydro-Quebec guy just told me they're not... Your comments please.

Here's a paper that talks about Arc Flash reduction solution when no main breaker is present on secondary side of transformer.

Hi all! This one is for people who use the Doble Test Set (M4000): A customer just bought a new dry-type transformer 2 MVA, 25000 / 600Y347 V. Nothing special... A service group (not us) go there and does the commissioning. They used the Doble Test Set to measure the ratios of the five taps...