STATIC STEPLESS CONTROL

[powerjunx]

hi folks..

i guess this query is quite old to you there..

""anyone knows about static stepless WOUND induction motor using SATURABLE CORE REACTOR on the secondary winding? the system is consist also with SCR'S, MAGNETIC AMPLIFIER MODULE, FREQUENCY MODULE, PLUGGING MODULE, and BIASING MODULE.""

i might say that this maybe is old to your idea because the system is used to tell you was built on the late 60's.

i could expect anybody who would like to share his/her views about this control system and i greatly appreciate it much.

thanks in advance..
yours,

fbjavier

 

[Fintan]

Hi fbjaviour
There was a system similar to this which was invented by a Russian.
A similar system is marketed by a company Magnastart.
SCR systems are marketed by a number of companies.
The most common & simplest system of stepless acceleration & speed regulation for wound rotor motors is the liquid resistance type. This is widely availabla .
If you require a contact , say where you are.
Regards

 

[jraef]

GE used to market this as a "Mag-Amp" starter, along with a few other manufacturers, but the concept lost favor because of the advent of less expensive and reliable SCR soft starters a number of decades ago. A company in India is trying to revive them again, as well as the Russian manufacturer mentioned above. Search this forum for Magnetic Amplifier and you will find previous threads with links, this one sums it up nicely thread237-54573



"Venditori de oleum-vipera non vigere excordis populi"

 

[Barry1961]

I worked around saturable reactors in military and found them to be very reliable. The only one I have run into outside the military was an old, riveted dual box beam, overhead crane. It had run for many, many years before the SCR's had failed.
While it was a very simple system and easy to fix, no one knew what it was. So this production crane had been down for over a week since even the factory people, P&H, did not know what type of speed control it was.
I guess the gist is that I think saturable reactors are great but I would not have one in my factory.

Barry1961

 

[powerjunx]

thanks fintand, jraef and barry!

fintan, id encounter about liquid resistor as what you mentioned about..way back 3 years ago..it was a Siemens 3000Kw Wound rotor motor. but anyway, i appreciate your comment.

jraef, thanks about your suggestion.. id already read some technical specs of such amplifier ..a MAG-AMP but what i tried to dig up is its application to wound rotor motor secondary winding.

to barry, im sure enough you familiar my query...the system i used to clarify is an overhead crane from P&H.

Yes, you are rigth Barry..it is very durable control since it was built on 1968 and until now it is working satisfactorily..

id already check all the devices such as SCR's, the modules, the motor itself, etc. and all was fine accept..

i had only this kind of problem that its speed control sometimes will drop down to go in malfunctions..i just keep on adjusting the rheostat of the modules to get back or restore its speed of the motor.. do you found the same problem id encounter?

maybe i beg a little favor to you to share some views..im sure you can contribute much about this! and besides i need some help about this because the manual of the system id work was never been found ..



thank you to all your comments folks.

 

[Barry1961]

The one I fixed was about 10 years ago so my memory is fuzzy. I just got called in as the friend of a friend of the local P&H Rep.

I remember they did not have any documentation and were having no luck finding any.

They had extra circuit boards which all had bad SCR's.

There was something besides SCR's bad but I can't remember what. For some reason I think the other bad component was due to physical damage.

I fixed all of the spares they had and gave the maintenance guy a hand full of SCR's and told him to replace all (four?) on the circuit board if it went bad in future.

The only advice I could give would be basic trouble shooting. Go to where you got a bad wave form then back track. Assuming it is an electrical problem.

If I was going be living with this I would draw a schematic of the board with some sketches of a good wave forms at key points.

Just taking a very wild guess, it could be a capacitor starting to dry out.

Sorry, not much help...

Barry1961