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#130404 - 04/03/06 07:38 PM Pot Transformers  
Dnkldorf  Offline
Member
Joined: Dec 2004
Posts: 1,064
nowhere usa
Here are a couple of pics of the Pots I am dealing with...

Looking at the nameplate, these are tappable. But exactly how do you move the HV taps on these? Appears to be a dial?

Mind my inexperience on Pots, Pls.....

(electure to post pics)

Dnk...


Tools for Electricians:

#130405 - 04/03/06 08:53 PM Re: Pot Transformers  
electure  Offline


Member
Joined: Dec 2000
Posts: 4,260
Fullerton, CA USA
[Linked Image]


[Linked Image]


#130406 - 04/03/06 09:53 PM Re: Pot Transformers  
circuit man  Offline
Member
Joined: Nov 2001
Posts: 273
saluda,s.c.
the tap changer is most likely inside the tank.it is most likely under oil. some are on the outside but very few.i have a couple of 3KVA GE pots similar to this.they are 7200 to 120/240.they have a screw for each pos.you back the screw out make your slection then put the screw back down.you would need to check the output voltages to see how close they are.this switch is there to compensate for when lower than nominal voltages are present.a word of caution some oil in the older transformers had PCB's in them.they are bad for us as well as the enviroment. let us know how it goes.


#130407 - 04/03/06 10:52 PM Re: Pot Transformers  
WFO  Offline
Member
Joined: Sep 2005
Posts: 202
Cat Spring, TX
You de-energize it first. What ever you do, don't change taps under load! [Linked Image]

Once it's de-energized, just move the dial to correspond to the percentage tap you want. You'll notice they are in 2.5% increments. If your output is 5% low on the 100% tap, go to the 95% tap. Essentially, you will be applying whatever the original incoming voltage was across 95% of the windings. The volts per winding will be higher on the primary, so the volts per winding on the secondary will be too. Do all three pots the same and double check your output before applying load.

By the way, I do business with Solomon quite often and find them to be very helpful and professional. I'm sure they would be willing to answer any questions you had about their equipment.

[This message has been edited by WFO (edited 04-03-2006).]

[This message has been edited by WFO (edited 04-03-2006).]


#130408 - 04/04/06 07:43 PM Re: Pot Transformers  
Dnkldorf  Offline
Member
Joined: Dec 2004
Posts: 1,064
nowhere usa
De-energize it? Why?.............

I was going to ask Trumpy to contact his email buddy, and ask him if he was man enough to do this live.... [Linked Image](sarcasm) [Linked Image]


Dnk...


#130409 - 04/04/06 10:45 PM Re: Pot Transformers  
gobblerhuntr  Offline
Member
Joined: May 2005
Posts: 23
TN
These pot may have an inspection plate on the top where the tap changer knob will be under it submersed in oil, if not you will have to take the lid off to get to the knob. Do yourself a favor and check the heat on the bushings before you go into it with a heat gun or infrared. If the bushings are showing hot or warm from the inside you may want to tighten them up while you are in there.

Oh yeah and DON'T drop any tools,washers, or other foreign matter in the pot, it makes for a long day. Not that I know anybody that has done that or anything...


#130410 - 04/04/06 11:18 PM Re: Pot Transformers  
WFO  Offline
Member
Joined: Sep 2005
Posts: 202
Cat Spring, TX
Quote:
"De-energize it? Why?............."

Didn't mean to come across like I was accusing you of being an idiot. It's just that I heard a story of an engineer once that actually did attempt to change taps through the handhole cover of an energized transformer.

I've always considered it prudent to state the obvious. Sorry.


#130411 - 04/05/06 07:24 AM Re: Pot Transformers  
Dnkldorf  Offline
Member
Joined: Dec 2004
Posts: 1,064
nowhere usa
WFO, I didn't take that way, I knew what you meant, I just poking fun at that guy who sent Trumpy an email, in regards to him being a man because he works on live stuff.... [Linked Image]

Dnk..


#130412 - 04/05/06 07:28 AM Re: Pot Transformers  
Dnkldorf  Offline
Member
Joined: Dec 2004
Posts: 1,064
nowhere usa
Ok guys, if the dial is under the oil, do you need to drain it out, or is the oil clear like vegetable oil, that you can see what your doing?

There is nothing wrong with the pots, I am just being curious, I don't know much about them...

Dnk...


#130413 - 04/05/06 04:53 PM Re: Pot Transformers  
gobblerhuntr  Offline
Member
Joined: May 2005
Posts: 23
TN
You should be able to see it ok, you might want to have some rubber gloves handy though as the oil could be a little warm. I'm talking thick rubber gloves not dishwashing ones.


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