11kV Slip-ring Motor Control Panel

Sorry my Physic helmet is away for recalibration!

Please explain why the drawings and control philosophy is not to hand.

Sorry, but you have too much non information enough to even think about what you wrote up here. You are cover too much info, and not enough detail for this process for anyone to even think about. Restate clearly what you need help with will help a great deal to get any answers.

Well, to put it in 1 line.... please send me a control schematic diagram for a typical 11kV Slip-ring motor starter.

Thank you for the help so far!

What kind of rotor resistance are you using? Liquid or wire wound, it makes a big diference.

Sir,

There are two very different types of "slip ring" motors. I don't know which one you are dealing with. If it has three "slip rings" then this is what we call a wound-rotor motor. If it has two "slip rings" you are dealing with a synchronous motor.

With a wound-rotor motor, the rotor is the secondary of what is essentially a rotating transformer winding. To vary the speed of the motor, you change the amount of resistance between the three slip rings. When the resistance is zero (shorted rings), the motor will run at its maximum speed; when it is high, it will run quite slowly. As another person noted, the circuit for a liquid resistor (salt water in a tank with three electrodes immersed into it) will be very different from that for fixed resistors and a drum switch to change from one resistance value to another.

With a synchronous motor, DC voltage is applied to the rotor after the motor has come up to near its full speed. This DC voltage then provides the force to pull the motor into a locked speed exactly in step with the mains frequency. For these, the starter has to include the DC power supply, circuits to monitor the frequency of the AC voltage induced in the slip rings while the motor is starting, and controls to connect the DC to these rings when the frequency is within a set percent of the mains frequency.

Tell us which type of motor you have, and we can give you additional help. Be warned, however, that starters for large synchronous motors can be very complex.

--John M.

Thanks John! They have mentioned slip-ring induction motor (& thus, not a sync motor).

Regards

From the original post:

"So far, the info. gathered is that the panel meant for 220VAC/110VDC will have water level, flow control & measuring system. Also, it will have High temp. detection, alarm/trip for pump thrust bearing, gear box & motor bearings."

Sounds like a liquid rheostat system to me. But is that what you know so far about something that you currently have? Or is that some random specification you found somewhere? Are you buying a new piece of equipment and want to prepare a specification for tender? Or did you come across a used system with no documentation and now you are trying to figure out how it works? Please help us to understand.

This company sells systems like this, maybe you can convince them to give you a copy of their guide form specifications.

http://www.flomatch.com/index.html

Well, this is a retro-fitting job. We have been asked only to supply the control panel. Starters are coming from elsewhere.

If you can quote me the price, I would be grateful!