I have a client who doesn't want to use any NEMA rated IEC devices on the control panel. It is a government project and he states his specifications condemns the use of any NEMA rated IEC devices. What are the advantages versus disadvantages for using a NEMA rated control relay versus an IEC...
The ratio is about 40-60 most being mineral oil. Can I still use the oil for Type II mineral oil use or is there a slight chance to reclaim the oil and use it as FR3?
I have a scenario where FR3 oil has been mixed with Type II mineral oil. A large amount of the oil (2000 gallons) has been mixed in the oil tanker and the question becomes can the oil be used for Type II mineral oil if it could be reclaimed? Can the oil even be reclaimed to use it as FR3 or...
Hi Bill,
The unit is new and has the following parameters:
15MVA oil filled unit, HV = 24940V GrdY, 125kV BIL; LV = 4160V GrdY, 60kV BIL
STD. Taps +/-2 x 2.5%
I will remove unit from tank and dismantle.
James
I want to add an air gap between the transformer core steel stack halves...can I use an expanded steel metal mesh screen as a means to provide the air gap to help cool the core in an oil filled transformer design? If not, what is the best method to provide the air gap to support the cooling of...
Thank you Skogsgurra, so if I have these "shorting plates" as you have called them are you saying I could use grinders perpendicular to the lamination to break these current paths?
The individual laminations are M-6 (0.014in)(0.35mm) thick (total stack build is 4in or 102mm), I can feel the...
Can core steel burr levels cause localized hot spots on power transformers? The burrs are on the edges of the core steel lamination what is the best tool to use to read the burr level? Please acknowledge.
Is there a standard which speaks to the layout of controls in a power transformer junction box? Or are there general rules to which to follow for general layouts of components inside of a control box for large power transformers?
Thank you prc and ScottyUK, this unit will be connected to a generator application, however the vector is the point I am having problems with and yes I understand the vector elements. But its the nameplate and the description that is causing me to scratch my head and wonder what the engineer...
what is meant by -Ydn1? The transformer is an oil filled design - 7100kVA with LV = 800V Delta with 45kVBIL and HV = 26000V Wye with 150kVBIL and an ESS (electro-static shield) grounded.
Typically the argument is that NEMA is easier to select because you do not need to know much about the application (due to robustness of the design), IEC is more catered to having to know the specifics of the application in order to select the appropriate relay. Another argument has been...
What is RoHS and how does this affect my selection of NEMA motor starters in the future? The reason for the inquiry is due to my friends in Europe indicates IEC starters are compliant to RoHS and I need to consider using IEC starters versus NEMA starters if I want to continue to sell my control...
I am struggling to understand the new impact RoHS will have on motor starters in the industry. If RoHS is calling for abandoning the use of Cad in contact material will the industry embrace the fact we will lose performance without the use of Cad in contacts? I already see actions in other...
I recently learned there will be a new requirement to do away with use of cadmium material in products(green-peace). The product I am using at this time is a NEMA starter where the power contact material is a silver cadmium oxide. The cadmium material provides great electrical life...
