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?
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...
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...
I have received a request from production personnel to weld flat strips onto the round steel rungs of various vertical fixed ladders. For various reasons I am opposed to this idea. I would like to hear from others on this subject both from a safety and from a mechanical point of view
I have generally accepted that distribution transformers can have the oil purified/regenerated online subject to certain limits of oil condition.
Recently I have been advised that this practice is risky.
I would like to know what is the general practice and school of thought in other places
We have a dip control panel in our 400v MCCs which I have never come across before. It consists quite basically of two Rhomberg slimline voltages relays set to detect a percentage over or under voltage. Occasionally they react and we have a system shut down. It is never clear whether there was...
Hi guys I got such a good response from from last thread so I want to put this one to the experts too. We have four large axial flow circulation pumps coupled to 350kW 6600 volt motor/gearbox via a large cardan shaft rotating at 330 rpm.
Bearing failure on the cardan shafts is far too frequent...
We regularly have failure with atomiser bearings ( thrust type ball, back to back). The shaft spins at 7000 rpm and the two sets of bearings are gravity fed with hydraulic oil Engen TQH 20/32 @ a rate of 20 millilitre per hour.
The shaft is vertically mounted so the top bearings gets oil first...
I have a problem with a siemens analogue input card sustaining damage. Thermocouple from an injection mould is connected to the AI card. The TCs are in close proximity to the 230v heater wires in same wireway in mould. Faults on heaters sometimes transfer to TC and TC cables carry a surge or...
I previously had Medoc on windows 98 on my laptop. Now I have loaded it on Windows XP. It works ok but the window is very small and I cannot enlarge it.
Any suggestions.
NB this is not the windows version of Medoc. I have the windows version on XP and it works fine but all of our company's...
