Recent content by Royherd27

Can the point to point test, (to determine the resistance between the main grounding system and all the major electrical frames, system neutral, etc) be made with an ordinary multimeter or does it need a special ground test tool? The NETA value of 0.5 ohm is widely accepted?

Megger States: "The Motor and Phase Rotation Tester permits the electrical contractor or industrial maintenance electrician to permanently connect and tape the terminals of the motor being installed, without having to first energize the motor by a temporary hookup from a power source, if...

Thanks Baluncore, and Windadct for your comments. Megger has a portable portable instrument for low voltage http://www.megger.com/us/products/ProductDetails.php?ID=1971&Description However I am still not sure if it might be used for Medium Voltage. Good thing you don't need to energize the...

Is it possible to check the phase rotation sequence of a Medium Voltage Motor (Up to 6 kV) with one instrument? Does the shaft need to be moving while it is being tested? If instead of one, there are two motors electrically connected in parallel, with a common source feeder. will it be...

Good day Jim, thanks for your answer. Basically I am in the range of 20 MVA Transformers and perhaps 15 MVA Motors, up to 35KV. I was told there could be online winding insulation monitoring relays, that would check if the Motor or Transformer insulation is leaking current to ground, with the...

Does anybody know if exist a kind of Insulation Monitoring Relay, to be Online (energized) all the time and be able to monitor the Transformers and Motors Winding continuously?

So far I have found these specials transformers are used almost on Off Shore Aplications, Siemens, GE and Scheneider have some experience already. They are using a Topside Transfomer (Boost up) and a Subsea Transformer (Boost down) Drives still are Topside. See atatched picture of one unit...

FOIWATER that is the key. we will feed the whole system with the transformer, downstream of the drive. The Million Dollar question is how do you name this kind of variable frequency transformers? Not all the manufacturers are able to make these units. Just Bust up Transformers for a range of...

Thanks PSPARKY, FOIWATER. Let me try to be more especific. I am working in specifications for a Power Transformer (5 MVA) to feed electrical motors SUBSEA, for different applications. Due to the voltage losses, the idea (already in the market) to elevate voltages comes along with the...

No I am not talking about communication. I am talking about Power Transformers, used to step up and step dowm voltage, with the special feature that the frequency (usually 50 or 60 Hz) will be variable within a range. Thanks

How are described in the Industry those transformers able to operate with a variable frequency? These transformers will be used downstream of a Frequency Drive. Anyone knows? Any specific characteristics? Thanks