Starting 6 kV , 1.35 MW Syncronous Motor 6

[Masbibe]

warros,

Yes it is dragline excavator type Esh 10/70. This is russian name but I dont know if you know it according to that name or some other american name.

 

[Masbibe]

warros,

When I asked you about this 2 DC motor, I concretly thing on 2 motors mechanicaly coupled and of course with same nominal ratings. Just to be more precize.

 

[edison123]

Thanks Bill. Got it.

Muthu

http://www.edison.co.in

 

[waross]

I assume that two motors are used to allow a reduction in the size of the ring gear or crown gear. If only one motor was used, the gear on the winch would have to be at least twice as strong. Two motors will also give some runaway protection should one motor fail. I am assuming that there are two motors on one end of the winch drum. If the motors are at opposite ends of the winch drum some of the same reasons still apply. Two motors will also balance the drive torque somewhat. Electrically I don't see a problem. I believe that this is a mechanical issue.

Bill
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"Why not the best?"
Jimmy Carter

 

[waross]

Back to your starting issues. Is there more than one excavator on-site? There is a very old technique for DOL starting of excavator motors on a weak system.
All the other excavators raise their buckets as high as possible. Then (co-ordinated by two way radio) they all drop their buckets in unison. As the buckets fall they regenerate. While the other machines are regenerating the machine coming in is started. How do you start the first one? With no machines running, the grid will often support one starting. Or one or two machines may have reduced current starting.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Masbibe]

warros,

thanks.

This is fantastic idea for starting motor.

I dont know detail about starting of excavators. I find some cheap sync reley so I will probably use it for synchronizing exitated SM on network.

 

[Skogsgurra]

Love that, Bill! PLS for you.

Even if it cannot be used in this case, it still is a great and fascinating idea.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[LionelHutz]

Hmm, I know we'd have little problem building an fairly economical phase-controlled rectifier capable of 900VDC but it wouldn't be a DC drive. You could current limit or ramp the voltage but that'd be about the extent of the control.

 

[edison123]

I bet all those machines have lots of tales to tell about you, Bill.

Muthu

http://www.edison.co.in

 

[waross]

Hello Muthu
One of the memorable service calls was first by dugout canoe and then by horse back to look at a small generator in the Moskito Coast region of Central America. Regrettably I was unable to repair the old beast. A shortage of resources, I was unable to find a battery suitable for flashing the field.
I can only do so much with a multi meter and no power of any kind. I have also worked on larger installations.


Bill
--------------------
"Why not the best?"
Jimmy Carter