transformers

Thread Starter

frankf

Joined Apr 21, 2014
1
I have a 9070T150D37 transformer
Pri. 575/600 V Sec. has taps 110/115/120 to 220/230/240 v

This is probably obvious but,

Why, when I apply 120 V to the primary and get 24 volts on the secondary?
what is the theory or rule of thumb applied?

Thanks
 
Last edited:

AnalogKid

Joined Aug 1, 2013
10,987
Why can you, or why can't you? Yes, you can.

Most transformers don't really know about primary and secondary. They are two inductors coupled with a magnetic medium. As a don't care example, a common way to build a low-cost inverter is to use a 12 V power transformer, but drive the "secondary" with a 12 V square wave and get a 120 V square wave out of the "primary".

As long as you don't overvoltage or overcurrent anything, the turns ratio and voltage ratio will hold for lower primary voltages. Large transformers do not work well with very light loads, but normal parts behave...normally.

ak
 

MaxHeadRoom

Joined Jul 18, 2013
28,619
I have a 9070T150D37 transformer
Pri. 575/600 V Sec. has taps 110/115/120 to 220/230/240 v

This is probably obvious but,

Why, when I apply 120 V to the primary and get 24 volts on the secondary?
what is the theory or rule of thumb applied?

Thanks
The secondary voltage is decided by the voltage applied to the primary and the direct turns ratio between primary winding and secondary.
Max.
 

crutschow

Joined Mar 14, 2008
34,285
..............................
Most transformers don't really know about primary and secondary. They are two inductors coupled with a magnetic medium.
..................
I would describe a transformer as a single inductor with multiple windings (except for an autotransformer which has a single winding).
 

wmodavis

Joined Oct 23, 2010
739
I have a 9070T150D37 transformer
Pri. 575/600 V Sec. has taps 110/115/120 to 220/230/240 v

This is probably obvious but,

Why, when I apply 120 V to the primary and get 24 volts on the secondary? Because the transformer has turns ratio primary:secondary of ~5:1 (600/120) or even believe it or not 120:24. That means if you apply 10 volts to pri you get 2 out of the secondary.
what is the theory or rule of thumb applied? Not a rule of thumb but simply the way transformers work. Better do some reading on transformer 'turns ratio'. Here is the first one that turned up when my friend Google went a lookin' for that very subject.

Thanks
https://www.google.com/search?q=transformer+turns+ratio
 
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