1909 GE 15 hp wound rotor controller T 133 R 4

[tgra4]

I'm trying to work out the resistance connections for this controller. Motor 15hp 220v 3 phase wound rotor in good condition.
Do not want to replace it as it is part of a vintage carousel. Has two sets of stepping contacts, not three.
Final step three contacts.
Resistors are missing.
GE have no records.
Des

 

[waross]

Does it have a nameplate?

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

 

[tgra4]

Thanks Waross. All the nameplate says is--
GE Controller T133 R, s/n 553711, NP 11378.
Motor is--
GE CO Induction Motor Type 1I 6-15A-1200 Form L Cycles 60 HP 15 Amps 38 Volts 220 Speed no load 1200 Full load -----
Schenectady NY USA

Des

 

[edison123]

What about rotor volts and current ? If it is mentioned on the nameplate, then any company making liquid rheostat starters should be able to find or make one.

If the nameplate doesn't have the rotor voltage and current, then you can do a open circuit test to find out the rotor volt and use it to calculate the rotor current.

 

[jraef]

GE motors division was bought out by Regal Beloit. I doubt they bought the old records, but you never know and it would be worth a call. If not, you are likely on your own. You could also try contacting resistor manufacturers who specialize in that, they likely have people with expertisein retrofitting old motors.

http://www.postglover.com/

(Post glover also bought IPC, another powerhouse in that business)

http://www.filnor.com/html/products/motor.html

http://www.powerohm.com/

"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

 

[LionelHutz]

Yes, does the rating plate have the rotor voltage and rotor current ratings?

Also, are you looking for any type of speed control with this thing? I doubt it but still should ask.

If it's just for starting then it's fairly simple to calculate the 3-steps of resistance if you have the rotor voltage and current.

If you do not have the rotor voltage and current ratings it is possible to figure them out but it will require you to find someone who can load the motor.

 

[tgra4]

I will need to out the resitance but that is easy .
My problem is to correctly connect the drum contacts of this controller, that has two sets each of four of contacts on the drum and work them into a 3 phse resistor bank keeping load currnts balanced as near as possible.
I worked with such controllers many years ago but most had balanced sets of 3 phase contacts.
Des

 

[edison123]

tgra4

Some wound rotor starters introduce delibrately unbalanced resistances in the three phases to produce better start torque. (I forgot the theory behind it).

I suggest you go for a new starter. It could not be that costly.

 

[CJCPE]

edison123:

I found the following re unbalanced resistances:

With reference to stator voltage: "Such voltage unbalance is equivalent to two balanced systems of voltages whose magnitudes are generally unequal to each other The larger, positive-sequence system of voltages energizes the winding to create a positive revolvong field and positive torque, while the smaller, negative-sequence system of voltages develops a negative revolving field and negative torque. Since the resultant torque is the difference between the opposing torques, being less than would be developed under normal balanced-voltage conditions, the speed is reduced."

"The principle of unbalanced-voltage speed control discussed in the foregoing article for a squirrel-cage motor can be applied equally well to the operation of a wound-rotor motor. In addition, the external rotor resistances can be varied and unbalanced to further control the speed of this type of motor."

Siskind, Charles S. "Electrical Control Systems in Industry" 1963

 

[edison123]

CJCPE

Wow. Thanks. That name triggers the memory. I need to go back to that book, which is somewhere in my library.

I am getting old..sigh..

 

[tgra4]

Thanks to you all. Did not recall that theory (I'm 75). I agree unbalance is no great problem and given that, I see a way to connect it. Des

DPS

 

[aolalde]

http://i35.tinypic.com/2vrzpeb.jpg

An open delta or V connection could work with 2 contactors per step . The currents are nor balanced.



.

 

[LionelHutz]

You only need 2 contacts per step for a wound rotor resistor control.

   -R---R---R-
  /   |   |   ]
 M--R---R---R-
  \   |   |   ]
   -R---R---R-

Each spot with a | gets a contact. 2 contacts per resistance step.

Most installs use 3-phase contactors with the 3rd contact between the top rung and the bottom rung but it's not necessary, it just balances the current between all 3 contacts. If you use 2 contacts with high enough current rating they work just as well.

 

[tgra4]

To Lionel,
Thanks, I had ruled this connection out because the four contacts on each of the two drums are solidly connected, but realise that this may not matter as the resistors are progressively shorted out.
Will draw it out to check.
Thanks, Des

DPS