Constant Voltage Transformer Manufacturers

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LMAO

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I am looking for constant voltage transformer manufacturers beside Sola. Something like this, 7.5kVA, 600V primary, etc. Who else makes these?
thanks
 
30kva too big?

30kva too big?

When you say 'something like this,' would this bigger one for 460v work? I would like to get rid of it someday....
 

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I can't recall the last time I used one. They used to be real common but it turns out most of the time they don't really do all that much good.
 
petersonra said:
I can't recall the last time I used one. They used to be real common but it turns out most of the time they don't really do all that much good.
Click to expand...

really?

I personally have never used it either but our a different department in our company uses them. They are the ones asking me to find one. I have never asked them why but I am guessing reason is the dirty line voltage. It is 600V that feeds a bunch of SCRs; these SCRs are hooked up to main line without any reactors in between so line voltage is degraded due to SCRs switching.... same line voltage also feeds sensitive 120V controls.
 
LMAO said:
really?

I personally have never used it either but our a different department in our company uses them. They are the ones asking me to find one. I have never asked them why but I am guessing reason is the dirty line voltage. It is 600V that feeds a bunch of SCRs; these SCRs are hooked up to main line without any reactors in between so line voltage is degraded due to SCRs switching.... same line voltage also feeds sensitive 120V controls.
Click to expand...
Do you have a dual trace scope? if so, put one probe on the input and one on the output. The output waveform is not a very nice sine wave. If there is an input disturbance the corresponding output disturbance is often worse. They really do not do much as far as cleaning up the power coming in.
 
Because the secondary resonant magnetic circuit is pumped by a saturated core, harmonics can come through at a higher amplitude than the fundamental.
You can get both normal (really bad) and sine wave (more or less) output models.
 
LMAO said:
really?

I personally have never used it either but our a different department in our company uses them. They are the ones asking me to find one. I have never asked them why but I am guessing reason is the dirty line voltage. It is 600V that feeds a bunch of SCRs; these SCRs are hooked up to main line without any reactors in between so line voltage is degraded due to SCRs switching.... same line voltage also feeds sensitive 120V controls.
Click to expand...

Really? Have they tested this concept or are they ASSuming it will work? Because when applied to the input of a highly non-linear power supply circuit, as most MODERN DC based systems now are, the CVT will "flat top" the output sine waves, which may (will) interfere with the functioning of the SCR firing system, and/or rectifier circuit. Some SCR firing schemes depend upon measuring the crossover point between sine waves (on polyphase units) to calculate the zero-cross point and know when to fire the SCRs. The pre-distorted output of the CVT can interfere with that sensing and cause the firing circuit to gate the SCRs at the wrong time. Aslo, the CVT is a very high impedance source, so that limits the power draw by the SCRs (which may be good or bad), but more importantly it lengthens the time they are conducting in each sine wave which can cause them to overheat if not compensated for up front in the component and heat sink selection. Bottom line, unless your system was DESIGNED to have a CVT ahead of it, don't just assume it is OK as a solution to power quality issues or you may get a rude awakening.
 
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