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Here is number two, some theory and math. Three phase "electricity" is where three currents and voltages from the same source feeds the same load. And why three phase? ( there is also sixphase but nt common) The three phases are 120 deg apart and there is no neutral current since the...

Mike, I do not have much knowledge of smaller plants. However, a three phase 3,5 MW generator driven by some kind of turbine or combustion engine will in many respects be similar to the large machines. The difference will be in the excitation system of the rotor winding. The small ones , (if...

Much of the electrical power we use today is generated by large prime movers ( turbines , mostly) driving large three phase generators. However, an increasing amount comes from wind turbines ( each unit up to maybe 20MW) and large scale PV farms. Germany is a prime example. Around 60 % of...

Hello to all. I have zero professional knowledge of many inputs above, that relates to US voltage levels and also a rather peculiar way to connect a delta winding. Please understand my shortcomings. What I do know are most theoretical and technical aspects of European and Asian electrical...

I have an inkling to post a 400/240 three phase residential and small business review. Some theoretical stuff, some practicalities, and a few opinions. Please let me know if it will add to the many excellent posts in GJ. Or better binned? Ola

My son works with air flow calculations on a fighter jet development. Once in a while he discusses practical issues with the body people. Who regularly weld rather thin titanium parts. Skilled TIG welders now have an experimental setup for laser welding of same. Not approved for flying parts...

A swedish nuclear power station had one( out of 4) 3 phase 10 kV networks single phase due to a faulty incomer CB ( 1982 vintage) Three phase motor load 26 MW, from 150 kW to 2 MW units. All overheated in less than 3 minutes and were scrapped. As was the feeding 25/10,7 kV 36 MVA transformer...

Nice job, and useful. Kudos Ola

When restoring a car in Telford, UK,( 1993) I found a company which heat stripped the entire car. All loose parts removed. Carbody was then put in an oven that increased the temp over 48 hours to 220 C Kept there for 6 hours and then cooled down to ambient over 48 hours. All paint...

The bearing in the pic looks like a sintered part made with small bronze balls and pressed to a unit This way the bearing can **** up lots of oil and stay oiled for many years of service. If you machine the hole for the shaft, you will loose most of the lube service. Ola

Get a cheap Ameter and install at the power source. Ola

Any UK spanners that are labelled with the size of the bolt, not the hex on the head. Ola

Volvo Ryan KE Jetronic turned out to be the most expensive fuel system ever made by Bosch. And they made many excellent systems but KE Jetronic was the typical result of any engineering that try to get a half bad system work by painting it over with another half bad technology. In sharp...

There is NO WORSE injection system than BOSCH KE Jetronic. One of the many real idiotic "features" is that the lower the fuel mass thru the injector ( ie on low load) the lower the atomization pressure and the worse the atomization when you need it the most. Another goodie : The fuel...

Older cars, OTOH, were made entirely of mild steel in very basic geometries, meaning that the entire vehicle would crush… crush your legs… crush your head… crush your kids… and so on. This is pure BS The MB W111/112 series of sedans, coupes and cabs had very advanced crumble zones and also...

Apply 220 V directly fused at 6 A to the motor leads for 1 second. If it runs, circuits feeding are faulty If it does not ru or hum, motor is faulty. WORK SAFELY. Ola

I have a drill made by Metabo 1964. Wonderful quality. METABO blue. Some nice issues The brushes have a built in spring with a small insulator. When brush is worn, the insulator will pop out and lift the brush from the commutator. No burned commutators. The chuck is self-locking and perfectly...

I am the happy owner of a Hitachi 2 channel 20 MHz scope from around 1988. It has a built in 12 V 1,8 Ah NiCd pack including charging system. Great when working on AC mains circuits, scope is floating. I bought the scope 2021 and opened it . ORIGINAL NiCd pack, marked March 1987. Full charge in...

Quote There are no transformers on these SMPS. Unquote Wrong There are no POWER FREQUENCY transformers on switch mode power supplies. HOWEVER There is a high frequency transformer, sometimes with several windings. in all switch mode power supplies that are used to run computers, amplifiers...

It is likely a Y-connected 380 to 400 V 50 Hz motor. The neutral point may be one of the "extra " wires. Most " industrial " european 3 phase motors 0,5-200 kW have 6 wires in the connection box. Can thus easily be connected Y or D. Any normally competent winding shop can reconnect it inside...