Gents here is one for the chemical boffins. Our plant regularly has SO2 (sulphur dioxide)gas present in the general atmosphere at about 5-15 PPM (occasionally much higher). Question. If this SO2 gas is drawn into an oil filled transformer via the breather in the normal manner in which...
Hi Guys here is an unusual one I had never experienced before. We shut down a plant for 2 weeks and upon start up one 350 kW 6600V pump motor tripped on start up, showing short circuit on Micom P225 relay. We did all the usual checks and inspections, mechanical and electrical. Then the motor was...
We are installing a 160kW VSD in a substation. I notice that contractors have routed the 6 single core flexible cables to the VSD through a steel gland plate. To my knowledge this is a NO NO because of inductance and eddy currents.
any Comments?
PS For such installations what size should the...
Having installed additional cables into a substation, I now need to re patch the fire resistant material which seals the cable entries.
Any recommendations for suitable material?
Hi Scotty and Kirbanda.
Kirbanda spot on with your observations. I deliberately do not refer to socket outlets because we are NOT supplying them via this 4 pin 63 amp sockets. We mostly certainly do have extremely strict wiring regs and all 230v 16 amp socket outlet must have 30mA EL protection...
Hi Liteyear. The only publication I DID find on the internet was an Oz one and it mentioned RCD for 63 amp outlets. However, those outlets were 3P+N+E and it was very clear that neutral must be connected for the RCD to work properly.
My sockets are 63 amp 3P+E as they supply motors only...
We have numerous 63 amp socket outlets, 400 3 phase VAC (50Hz) for powering fans etc in our plant. Traditionally they are protected by overcurrent MCBs which have integral earth leakage protection (RCD) rated at 30 milliamp.
Our national wiring regulations stipulate EL protection for 16 amp 230...
Hi Mike and Bill
Thanks for your responses.
When we open pipe flanges, man ways to tanks etc we do it via a permit to work system. Within that permit is a mini risk assessment and all the conditions for safe opening of the said flange or tank are listed.
These precautions include electrical...
Following two incidents in 6 months where staff have sustained burns from hot liquids I have been tasked with review of suitable PPE and suggested requirements/procedures. I would like to hear from other who work in any plant (eg pulp and paper) where hot liquids are transported. Our hot liquids...
I am experiencing persistent problems with oil quality on a 5 MVA 11/6.6kV transformer. Moisture levels from samples taken twice yearly are consistently high. We do in situ oil purification annually but the problem returns after a few months.
A local company has suggested removing the...
Many thanks for the response and advice chaps. From the measurements you all use I am guessing most of you are based in the USA.
It is always good to hear from people in different countries.
