Buck Boost XFMR

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PAUL50

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Pensacola Florida
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J. Electrician
Primary is 120/240
Secondary is 16/32
I have 208 V and I was told to hook the transformer up backwards. That means putting my 208 leads on the secondary side and trying to get to 40 out of the primary side. Is this possible? All it did was tripped my main breaker when I turned it on.
 
So you hooked up 208 volts to the 16 volt secondary? That could give you 1560 volts on the primary depending on how it was wired. May I ask who told you to wire it this way?
120/16=7.5*208=1560 volts
 
Primary is 120/240
Secondary is 16/32
I have 208 V and I was told to hook the transformer up backwards. That means putting my 208 leads on the secondary side and trying to get to 40 out of the primary side. Is this possible? All it did was tripped my main breaker when I turned it on.

The primary side is the side that is by definition connected to the grid source. Perhaps you meant you want 40V of the secondary side.

The turns ratio of this transformer is 240:32 = 7.5
The desired turns ratio is 208:40 = 5.2

You would need to reduce the turns ratio from 7.5 to 5.2, by changing the tap on the transformer to the 70% position on the primary side, if it has one. I've never seen a transformer with this extreme tap adjustment, so this is most likely the wrong transformer entirely.
 
Primary is 120/240
Secondary is 16/32
I have 208 V and I was told to hook the transformer up backwards. That means putting my 208 leads on the secondary side and trying to get to 240 out of the primary side. Is this possible? All it did was tripped my main breaker when I turned it on.
 
So you hooked up 208 volts to the 16 volt secondary? That could give you 1560 volts on the primary depending on how it was wired. May I ask who told you to wire it this way?
120/16=7.5*208=1560 volts
My post is a little wrong and not sure how to edit it yet. I was told to take my 1ph 208 and feed the secondary side which is 16/32 and out of my primary side I would get my 1ph 240. All it does is trip the breaker feeding the xfmr. I have never hooked me in reverse but I do understand you can.
 
My post is a little wrong and not sure how to edit it yet. I was told to take my 1ph 208 and feed the secondary side which is 16/32 and out of my primary side I would get my 1ph 240. All it does is trip the breaker feeding the xfmr. I have never hooked me in reverse but I do understand you can.
Look at the image I posted.
 
If you actually want 40 volts output, you don't have the right thing to do it with.

If this was a mistype and you are trying to boost 208 to 240 you have the right thing (amount of kVA needed is another issue but hasn't been mentioned). All you need to do is apply incoming 208 to the primary, configured for 240 (connect so each 120 volt segment is in series) then connect the secondary configured for 32 volts (each 16 volt segment in series) in series with the primary. Two outermost leads will have 240 volts, but capacity is limited by the VA rating of the unit.

dashes below represent winding segments items in parenthesis represent what is worded in the parenthesis
(208V L1)---------(midpoint of primary)------------(208V L2)---------(secondary terminal)-----------(secondary midpoint)---------(secondary terminal and output lead that is 240 volts to 208V L1)
 
My post is a little wrong and not sure how to edit it yet. I was told to take my 1ph 208 and feed the secondary side which is 16/32 and out of my primary side I would get my 1ph 240. All it does is trip the breaker feeding the xfmr. I have never hooked me in reverse but I do understand you can.

The ratio between the voltages on opposite sides of the transformer, is based on the ratio of turns on the primary to secondary sides. If you are trying to boost 208V to 240V, you need a transformer with a 1:0.866 turns ratio. I.e. approximately 15 turns on the 240V side for every 13 turns it has on the 208V side. It also needs to be rated for the maximum voltage between the two sides, and the KVA of the Volts*Amps you desire to transform, so that the internal insulation is "strong enough" and that it has enough thermal management capacity to handle the current on both sides.
 
So you hooked up 208 volts to the 16 volt secondary? That could give you 1560 volts on the primary depending on how it was wired. May I ask who told you to wire it this way?
120/16=7.5*208=1560 volts
. It’s on a pole and I only have single phase at the pole. 2 hots and a ground. That’s all. This buck boost transformer is not three-phase it is single phase. The panel is 208/120 single phase, the object they are trying to hook up is 240 single phase. I was given the buck boost transformer and was told to feed the xfmr from the existing 208 panel into the secondary side of the buck boost transformer which is 16/32. Then was told the primary would then have 240. Ive never hooked one up backwards. It just trips the breaker and I can find no reason why unless the xfmr is bad.
 
If you actually want 40 volts output, you don't have the right thing to do it with.

If this was a mistype and you are trying to boost 208 to 240 you have the right thing (amount of kVA needed is another issue but hasn't been mentioned). All you need to do is apply incoming 208 to the primary, configured for 240 (connect so each 120 volt segment is in series) then connect the secondary configured for 32 volts (each 16 volt segment in series) in series with the primary. Two outermost leads will have 240 volts, but capacity is limited by the VA rating of the unit.

dashes below represent winding segments items in parenthesis represent what is worded in the parenthesis
(208V L1)---------(midpoint of primary)------------(208V L2)---------(secondary terminal)-----------(secondary midpoint)---------(secondary terminal and output lead that is 240 volts to 208V L1)
Missed some the posts before I posted.

Basically you are putting 208 across the primary then putting the secondary in series with the primary and the added or subtracted effect depending on how it is connected gives you the bucked or boosted voltage. Polarity of each coil in relation to other coils is important in determining if you get buck or boost.

Documentation that comes with the transformer tells you how to connect it for all the various possibilities.

One should use calculators or charts provided by manufacturer before even selecting a transformer to get most optimum unit for your application, and that calculator/chart will tell you which wiring diagram applies for your application also.
 
Missed some the posts before I posted.

Basically you are putting 208 across the primary then putting the secondary in series with the primary and the added or subtracted effect depending on how it is connected gives you the bucked or boosted voltage. Polarity of each coil in relation to other coils is important in determining if you get buck or boost.

Documentation that comes with the transformer tells you how to connect it for all the various possibilities.

One should use calculators or charts provided by manufacturer before even selecting a transformer to get most optimum unit for your application, and that calculator/chart will tell you which wiring diagram applies for your application also.
I was givin nothing lol
 
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