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jameskitching avatar image
jameskitching asked

Victron 3600W Isolation Transformer stepping up voltage???

Hi I wondered if some one could help we are using the victron 3600 to prove our equipment cabinets can work using IT mode. our input voltage into the transformer is 240V and the output is 256V?!?! I was under the impression it was 1:1 ratio so input=output. It is causing our ATS (automatic transfer switch) to persistently switch between A and B feed due o over voltage protection. Can anyone explain why we are having this issue


Thanks,


James.

voltageovervoltageIsolation Tranformer
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5 Answers
Johannes Boonstra (Victron Energy Staff) avatar image
Johannes Boonstra (Victron Energy Staff) answered ·

Yes, the transformer is lifting the voltage a few % and the reason behind this is that this will compensate for the voltage drop which normally happen when a transformer is loaded (close/at its maximal power) and the fact that the transformer is often used in the marina on board boats. These marinas have a tendency to have a low AC voltage due to the long cabling.

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omsav avatar image omsav commented ·

I have Victron Isolation Trafo 3600w that also delivering 254Vac out this making problem to start my Whisper Power System to supply shore power to my boat. This is related there is a “absolute maximum input voltage” set to 250vac at Whisper Power system. The Victron Isolation Trafo is delivering perfect voltage in/out in a load Situation. The problem to the system started

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farco-as avatar image
farco-as answered ·

@Johannes Boonstra (Victron Energy Staff)

Our issue (3600W ITR):

No load: 244V in / 263V out.

5A load: 244V in 254V out.

This is to high for this application. Any way to get around this?

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Johannes Boonstra (Victron Energy Staff) avatar image
Johannes Boonstra (Victron Energy Staff) answered ·

Hi, The thing is that this input is probably pretty high (>235Vac). Due to the extra windings in the transformer (to compensate for the losses under load) then zero load voltage can indeed be 5-6% higher then the input voltage. If this is a often used AC source/shore you might want to re-wire the transformer (swap input /output). Please contact Victron service for this.

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maddin avatar image
maddin answered ·

Hi, we have same "problem" . AC in 235 v , out is 247 v and kills the equipment ! Is this on all isolation-transformers or only the 3600w ?

How to eliminate this function on a easy way ?


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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·

That cannot be changed it's physics.
The secondary coil have a few more winding and that results in a higher output voltage.

It is also in the datasheet:
1619430420039.pngWhat we did (but this is out of warranty!) is to swap the primary and secondary coil.
This will result in a lower output voltage(224V at 235V input).

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1619430420039.png (32.3 KiB)
pekie avatar image pekie Matthias Lange - DE ♦ commented ·
Hello Matthias, I have this problem too with my transformer. Can you tell me how to swap the coils?

Thanks, Remy

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Rod avatar image
Rod answered ·

This “Swap” changing the input and output connections…. Interferes with the auto detect version?


It will be great if a Victron person explains how is the internal process for automatic detection and commuting.

Is it a break after make switching?

Does the soft start, works every time it conmutes?

for a 90V input, is the output 90V +/-5%…

Or will the output keep 115V or 230V?

What is the status of the internal input and outut tabs connection when out of voltage range (i.e 50V, 160V, 280v)

Understanding the operation’s principle could guide us to understand, and succeed on our projects..


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