Synchronous motor controllers
Synchronous motor controllers
(OP)
We have 5 1250hp 4160v synchronous motors at the plant. They are controlled by a GE Multilin SPM, a GE Multilin SR469 and also a Motortronics MVC Plus soft start. I'm wondering if the SR469 is neccesary in this type of setup. The MVC seems to have the neccesary protection, and already provides most of the protection. I'm trying to figure out exactly what each unit is protecting, but the prints leave alot to be desired. Does anyone have any ideas why we would need the extra relay? I'm trying to find a sequence of operation, and also have been going through the prints and settings trying to identify the trips and controls.
The control system seems overly complex, and luckily we have not had any trouble yet. The starters are about 2 yrs old and I'd like to get real familiar with them before we have trouble. The equipment they drive is critical, and there will be lots of pressure in the event of a breakdown.
The control system seems overly complex, and luckily we have not had any trouble yet. The starters are about 2 yrs old and I'd like to get real familiar with them before we have trouble. The equipment they drive is critical, and there will be lots of pressure in the event of a breakdown.





RE: Synchronous motor controllers
That said, there are a few differences, most of which are never used by anyone. But just in case you do, here they are:
The 469 is capable of waveform capture and storage for future retrieval by some sort of higher level system. Not terribly useful, but there you go.
The 469 can take in up to 2 external analog inputs for things such a vibration sensors etc., the MVC cannot. However, for far less than the $7k cost of a 469, you can use separate analog limit alarm relays and trip the digital inputs.
The 469 can drive up to 4 external analog outputs, the MVC cannot. Again, external analog sensors are less expensive if that is an issue.
The 469 is capable of accepting 3 additional CTs if you want to do differential protection. Not usually done in motors below 2500HP though.
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RE: Synchronous motor controllers
RE: Synchronous motor controllers
RE: Synchronous motor controllers
RE: Synchronous motor controllers
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: Synchronous motor controllers
The 469 provides a lot of control and data acquisition capabilities that the MVC lacks. It is a good choice for a control and data platform.
Look at your control elementary diagram and see where the output relays of each device are used. This may give you an idea of what the designers were trying to accomplish. I have seen a Multilin relay installed with NO protective function at all. The client liked his old protection, but he wanted the metering functions provided by the Multilin.
old field guy
RE: Synchronous motor controllers
I'm still digging for as much info as I can get. There at least 10 different schematics for each mill.