Isolation transformer safety for testing?

[SRG]

Dear Group it's been a while....

I'm interested in knowing if a 220v - 110v 3.3KVA isolation
transformer such as those
used in the building trade (yellow boxes in the UK) would provide
adequate safety when working on SMPS's?

I was also thinking of adding a variac to allow variable ac voltage
input thus enabling testing at a much lower voltage.

Any advice would be much appreciated.
TIA
Steve.

 

[Jerry G.]

By the sound of things, you want to service 110V equipment.

You can get a variac with isolated output, thus not requiring the extra
transformer.

Is it worth spending all this money in time and equipment to service SMPS's
when they are so low in cost to replace, and complex to service?

--

Greetings,

Jerry Greenberg GLG Technologies GLG
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Dear Group it's been a while....

I'm interested in knowing if a 220v - 110v 3.3KVA isolation
transformer such as those
used in the building trade (yellow boxes in the UK) would provide
adequate safety when working on SMPS's?

I was also thinking of adding a variac to allow variable ac voltage
input thus enabling testing at a much lower voltage.

Any advice would be much appreciated.
TIA
Steve.

 

[Steve Bell]

By the sound of things, you want to service 110V equipment.

You can get a variac with isolated output, thus not requiring the extra
transformer.

Is it worth spending all this money in time and equipment to service SMPS's
when they are so low in cost to replace, and complex to service?

Not all SM PSU's are throw away uneconomical devices. The company I used to
work for 7/8 years ago had 3 techs continuously repairing PSU's, now they
have 6, sometimes 7 techs doing this work. We used large isolating
transformers, variacs and active loads.

Steve Bell

 

[CBarn24050]

Is it worth spending all this money in time and equipment to service SMPS's

when they are so low in cost to replace, and complex to service?

There are plenty of custom psus around that ere very expensive to replace, some
are not even made anymore.

 

[CJT]

By the sound of things, you want to service 110V equipment.

You can get a variac with isolated output, thus not requiring the extra
transformer.

I thought by definition a "variac" is an _autotransformer_ combining
primary and secondary, and so offers no isolation.

 

[Sam Goldwasser]

I thought by definition a "variac" is an _autotransformer_ combining
primary and secondary, and so offers no isolation.

The term "Variac" normally does mean an autotransformer but it's certainly
clear what he means. And variable isolation transformers do exist.

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