Dodgy step down tranny

[Phil Allison]

"kreed"

Interesting too how the 3kw version seems to have (hard to read) a
32amp breaker on the front panel.
Unless they are fusing the secondary with it.

**Bound to be in the secondary.

The unit I have here has the fuse fitted in the primary cos at 18 amps
nominal - the secondary side would need a fuse and fuse holder bigger than
is cheaply available.

The toroidal auto-tranny inside looks roughly made and carries no labelling
at al.

Dimensions are 120mm dia and 75mm high.

There are just three light gauge, flexible wires coming out.


..... Phil

 

[Sylvia Else]

On 9/02/2011 1:37 PM, Phil Allison wrote:

"Stupider than Anyone Else Alive or Dead.

** Burn the witch.


Then it's not the same as the 2kW version on the website, which weighs
12.5 kg. Indeed, it has a similar weight to the 500W version.

Perhaps there's a QA problem with labelling.


** Funny about the 10amp fuse being fitted ....

That could just be a consequence of the mislabelling,

** Blah, blah blah,

The fuse holder is NOT labelled at all.

Did I say fuse holder labelling?

It seems clear that this is not a variant of the currently offered 2kW
model,

** The unit is from the same supplier - that is all I ever claimed.

FFS read the OP again and again til you GET IT !!


that it's not being used in an application that requires anything
approaching that,

** So fucking what ??????????

In the future it may have an owner who needs the whole 2kW.

The owner may loan it to another to use with say 2kW of 110 volt lighting.

Smoke will get out in about 1 minute if he does that.

suggesting that the purchaser probably didn't expect it to be a 2kW
transformer either.


** Yawnnnnnnnnnnnnnnnnnnnnn....



.... Phil

I agree there's a concern about this specific transformer. But maybe
that's all it is - one specific transformer that for some obscure reason
has been mischaracterised. You did refer to the supplier's eBay shop,
which implies that you thought that was somehow relevant.

Presumably you'll replace the fuse with something appropriate.

Sylvia.

 

[Phil Allison]

"Trevor Wilson"

**High end audio is a different world to that which most people inhabit.
Perception is more important than performance in most instances.

** That is true nearly everywhere.

Especially politics.


...... Phil

 

[Sylvia Else]

On 9/02/2011 1:14 PM, Phil Allison wrote:

"Stupider than anyone Else on Earth"


In this particular case it's become apparent that there's a disparity
between the mass of the example Phil has, and the mass of the 2kW model on
the website.

** They are two different models.

I suppose the website could just be mis-stating the mass, but anyone who
paid attention to it on the website would notice the difference as soon as
the transformer was delivered.

** FFS - read the OP.

The stepdown I have here is probably several years old.

Your point being? That the seller used to be a ripoff merchant, but is

now selling quality goods?

Sylvia.

 

[keithr]

On 9/02/2011 12:55 PM, Trevor Wilson wrote:

**The mass SHOULD be a giveaway. However, I've worked on more equipment than
I care to think about, where the manufacturer (usually Chinese) has
incorporated large pieces of non-structural steel to increase the mass of
the product. I've even seen all-aluminum chassis devices, where steel has
been used to increase mass. The first time I saw this done, was with an
Onkyo (Japanese) CD player, back in the 1990s. The CD player weighed in at a
hefty 25-odd kg. More than half that mass was the result of a large piece of
steel bolted to the base plate. Without opening the player, an owner would
never realise that it was the reason for all that mass.

Mild steel plate is still less expensive than copper and laminated iron (in
the shape of a transformer).

I suppose that they could claim it to be a vibration damper. Stranger
things have been know with "HiFi" devices.

 

[Sylvia Else]

On 9/02/2011 1:38 PM, kreed wrote:

On Feb 9, 11:55 am, "Trevor Wilson"<tre...@rageaudio.com.au> wrote:
Sylvia Else wrote:
On 9/02/2011 12:27 PM, kreed wrote:
On Feb 9, 11:00 am, Sylvia Else<syl...@not.here.invalid> wrote:
On 9/02/2011 10:53 AM, Phil Allison wrote:

** Hi all,

a repair job arrived last night accompanied a step-down tranny - the
repair is a US made amplifier that requires 120 volts AC at
60Hz - but copes with 50 Hz all right.

The step-down tranny was supplied here in NSW by an eBay seller:

See:www.rhinotools.com.au

It is labelled as "2000W' and 240V to 110 V " plus the words "Korean
Technology".

The unit I have here is similar to ones on his eBay shop now, but
not identical.

Inside is a toroidal **autotransformer**.

Problems:

The unit cannot possibly deliver 2000 watts - the max continuous
rating should be no more than 500 watts. The resistance of the 240
volt winding is 5.6 ohms at room temp. Do the math.

The unit does not output 110 volts under load - tested with a
500 watt resistive load, it outputs only 103 volts.

The only protection for the transformer is via a fuse holder on
the back fitted with a glass fuse rated at 10A - though the
holder is not labelled with any value.

Anyone smell smoke ??

Well, it would certainly get quite hot at its rated output, but I
don't think I'd expect smoke. If it's the same size as the one on
the website, it's reasonably large, and it only has to get rid of
50-60W.

The size of the case is irrelevant, they could shove a very small
transformer inside
you need to see the internal transformer to make such a judgement.

I'm assuming the case is as small as they can make it, simply because
that reduces the cost, and increases the potential profit.

Also, it weighs 12 kg, so it either contains a metal brick, or has a
hefty transformer.

Anyway, Phil has correctly pointed out that I've made a mistake in
calculating the heat to be dissipated given the resistance he
measured.
Yet I can't help thinking that something that heavy should be able to
achieve more than 500W. Perhaps Phil could post its exterior
dimensions - it may simply have been mislabelled.

**The mass SHOULD be a giveaway. However, I've worked on more equipment than
I care to think about, where the manufacturer (usually Chinese) has
incorporated large pieces of non-structural steel to increase the mass of
the product. I've even seen all-aluminum chassis devices, where steel has
been used to increase mass. The first time I saw this done, was with an
Onkyo (Japanese) CD player, back in the 1990s. The CD player weighed in at a
hefty 25-odd kg. More than half that mass was the result of a large piece of
steel bolted to the base plate. Without opening the player, an owner would
never realise that it was the reason for all that mass.

Mild steel plate is still less expensive than copper and laminated iron (in
the shape of a transformer).

--
Trevor Wilsonwww.rageaudio.com.au


Also, certain products might have to "feel to be a certain weight" in
relation to its physical volume, for the consumer to perceive them to
be a "quality" product.

You would know more about it than I would - being in the industry -
but I think high end audio would fall into this category ?

Still, 25kg?

Any consumer who expects a CD player to weigh that much fully deserves
the hernia they get when trying to install it.

Sylvia.

 

[Phil Allison]

"Stupider than anyone Else on Earth"

In this particular case it's become apparent that there's a disparity
between the mass of the example Phil has, and the mass of the 2kW model
on
the website.

** They are two different models.

I suppose the website could just be mis-stating the mass, but anyone who
paid attention to it on the website would notice the difference as soon
as
the transformer was delivered.

** FFS - read the OP.

The stepdown I have here is probably several years old.

Your point being?

** Jesus fucking Christ !!

It ain't on sale right now - but maybe hundreds are out there.

It's a nice example of eBay fraud too.

Beware.


..... Phil

 

[Sylvia Else]

On 9/02/2011 2:00 PM, Phil Allison wrote:

"Stupider than anyone Else on Earth"


In this particular case it's become apparent that there's a disparity
between the mass of the example Phil has, and the mass of the 2kW model
on
the website.

** They are two different models.

I suppose the website could just be mis-stating the mass, but anyone who
paid attention to it on the website would notice the difference as soon
as
the transformer was delivered.

** FFS - read the OP.

The stepdown I have here is probably several years old.

Your point being?


** Jesus fucking Christ !!

It ain't on sale right now - but maybe hundreds are out there.

OK, so what are you doing about it besides winge on aus.electronics?

Have you contacted the supplier? The Department of Fair Trading? Maybe
there should be a product recall.

It's a nice example of eBay fraud too.

It may have been. It may not. Depends how it was described *on eBay* at
the time.

Sylvia.

 

[Sylvia Else]

On 9/02/2011 1:52 PM, kreed wrote:

On Feb 9, 12:11 pm, Sylvia Else<syl...@not.here.invalid> wrote:
On 9/02/2011 12:55 PM, Trevor Wilson wrote:



Sylvia Else wrote:
On 9/02/2011 12:27 PM, kreed wrote:
On Feb 9, 11:00 am, Sylvia Else<syl...@not.here.invalid> wrote:
On 9/02/2011 10:53 AM, Phil Allison wrote:

** Hi all,

a repair job arrived last night accompanied a step-down tranny - the
repair is a US made amplifier that requires 120 volts AC at
60Hz - but copes with 50 Hz all right.

The step-down tranny was supplied here in NSW by an eBay seller:

See:www.rhinotools.com.au

It is labelled as "2000W' and 240V to 110 V " plus the words "Korean
Technology".

The unit I have here is similar to ones on his eBay shop now, but
not identical.

Inside is a toroidal **autotransformer**.

Problems:

The unit cannot possibly deliver 2000 watts - the max continuous
rating should be no more than 500 watts. The resistance of the 240
volt winding is 5.6 ohms at room temp. Do the math.

The unit does not output 110 volts under load - tested with a
500 watt resistive load, it outputs only 103 volts.

The only protection for the transformer is via a fuse holder on
the back fitted with a glass fuse rated at 10A - though the
holder is not labelled with any value.

Anyone smell smoke ??

Well, it would certainly get quite hot at its rated output, but I
don't think I'd expect smoke. If it's the same size as the one on
the website, it's reasonably large, and it only has to get rid of
50-60W.

The size of the case is irrelevant, they could shove a very small
transformer inside
you need to see the internal transformer to make such a judgement.

I'm assuming the case is as small as they can make it, simply because
that reduces the cost, and increases the potential profit.

Also, it weighs 12 kg, so it either contains a metal brick, or has a
hefty transformer.

Anyway, Phil has correctly pointed out that I've made a mistake in
calculating the heat to be dissipated given the resistance he
measured.
Yet I can't help thinking that something that heavy should be able to
achieve more than 500W. Perhaps Phil could post its exterior
dimensions - it may simply have been mislabelled.

**The mass SHOULD be a giveaway. However, I've worked on more equipment than
I care to think about, where the manufacturer (usually Chinese) has
incorporated large pieces of non-structural steel to increase the mass of
the product. I've even seen all-aluminum chassis devices, where steel has
been used to increase mass. The first time I saw this done, was with an
Onkyo (Japanese) CD player, back in the 1990s. The CD player weighed in at a
hefty 25-odd kg. More than half that mass was the result of a large piece of
steel bolted to the base plate. Without opening the player, an owner would
never realise that it was the reason for all that mass.

Seems an odd thing to do with a CD player, given that I wouldn't have
thought a consumer would expect it to be particularly heavy - and
certainly not 25kg heavy.



Mild steel plate is still less expensive than copper and laminated iron (in
the shape of a transformer).

Yes.

In this particular case it's become apparent that there's a disparity
between the mass of the example Phil has, and the mass of the 2kW model
on the website. I suppose the website could just be mis-stating the
mass, but anyone who paid attention to it on the website would notice
the difference as soon as the transformer was delivered.

Sylvia.


The average consumer would not know what weight to expect.

I agree. The point I was making is that it would make little sense for
the website to be overstating the weight, because the only people who
would pay attention to it for the purpose of assessing power rating
would also notice immediately that what they received was too light.

They also would not
know there was a problem until they tried to run it at full load, and
found that they had
an appliance not working effectively.


There is also the issue of mains frequency, especially with
transformers, ballasts etc that are made for 60hz.
Induction motors would also run slowly.

Certainly that's something the user has to be aware of, but the web site
makes no representation that the frequency is changed.

Sylvia.

 

[Phil Allison]

"Stupider than anyone Else on Earth"

Your point being?


** Jesus fucking Christ !!

It ain't on sale right now - but maybe hundreds are out there.

OK, so what are you doing about it besides winge

** No whinging for me - the POS is not mine.

I am publishing simple a " heads up".

For interest sake.

Have you contacted the supplier? The Department of Fair Trading? Maybe
there should be a product recall.

** I cannot see there is a major safety issue - once the tranny begins to
burn, the 10 amp fuse will blow.

But any purchasers who have one burn out like this are entitled to a
refund.

It's a nice example of eBay fraud too.

It may have been. It may not.

** FUCKING bollocks.


..... Phil

 

[kreed]

On Feb 9, 11:55 am, "Trevor Wilson" <tre...@rageaudio.com.au> wrote:

Sylvia Else wrote:
On 9/02/2011 12:27 PM, kreed wrote:
On Feb 9, 11:00 am, Sylvia Else<syl...@not.here.invalid>  wrote:
On 9/02/2011 10:53 AM, Phil Allison wrote:

** Hi all,

a repair job arrived last night accompanied a step-down tranny  - the
repair is a US made amplifier that requires 120 volts AC at
60Hz  - but copes with 50 Hz all right.

The step-down tranny was supplied here in NSW by an eBay seller:

See:www.rhinotools.com.au

It is labelled as "2000W' and  240V to 110 V "  plus the words "Korean
Technology".

The unit I have here is similar to ones on his eBay shop now, but
not identical.

Inside is a toroidal **autotransformer**.

Problems:

The unit cannot possibly deliver 2000 watts -  the max continuous
rating should be no more than 500 watts. The resistance of the 240
volt winding is 5.6 ohms at room temp. Do the math.

The unit does not output 110 volts under load  -  tested with a
500 watt resistive load, it outputs only 103 volts.

The only protection for the transformer is via a fuse holder on
the back fitted with a glass fuse rated at 10A  - though the
holder is not labelled with any value.

Anyone smell smoke ??

Well, it would certainly get quite hot at its rated output, but I
don't think I'd expect smoke. If it's the same size as the one on
the website, it's reasonably large, and it only has to get rid of
50-60W.

The size of the case is irrelevant, they could shove a very small
transformer inside
you need to see the internal transformer to make such a judgement.

I'm assuming the case is as small as they can make it, simply because
that reduces the cost, and increases the potential profit.

Also, it weighs 12 kg, so it either contains a metal brick, or has a
hefty transformer.

Anyway, Phil has correctly pointed out that I've made a mistake in
calculating the heat to be dissipated given the resistance he
measured.
Yet I can't help thinking that something that heavy should be able to
achieve more than 500W. Perhaps Phil could post its exterior
dimensions - it may simply have been mislabelled.

**The mass SHOULD be a giveaway. However, I've worked on more equipment than
I care to think about, where the manufacturer (usually Chinese) has
incorporated large pieces of non-structural steel to increase the mass of
the product. I've even seen all-aluminum chassis devices, where steel has
been used to increase mass. The first time I saw this done, was with an
Onkyo (Japanese) CD player, back in the 1990s. The CD player weighed in at a
hefty 25-odd kg. More than half that mass was the result of a large piece of
steel bolted to the base plate. Without opening the player, an owner would
never realise that it was the reason for all that mass.

Mild steel plate is still less expensive than copper and laminated iron (in
the shape of a transformer).

--
Trevor Wilsonwww.rageaudio.com.au

Also, certain products might have to "feel to be a certain weight" in
relation to its physical volume, for the consumer to perceive them to
be a "quality" product.

You would know more about it than I would - being in the industry -
but I think high end audio would fall into this category ?

 

[kreed]

On Feb 9, 12:11 pm, Sylvia Else <syl...@not.here.invalid> wrote:

On 9/02/2011 12:55 PM, Trevor Wilson wrote:



Sylvia Else wrote:
On 9/02/2011 12:27 PM, kreed wrote:
On Feb 9, 11:00 am, Sylvia Else<syl...@not.here.invalid>   wrote:
On 9/02/2011 10:53 AM, Phil Allison wrote:

** Hi all,

a repair job arrived last night accompanied a step-down tranny  - the
repair is a US made amplifier that requires 120 volts AC at
60Hz  - but copes with 50 Hz all right.

The step-down tranny was supplied here in NSW by an eBay seller:

See:www.rhinotools.com.au

It is labelled as "2000W' and  240V to 110 V "  plus the words "Korean
Technology".

The unit I have here is similar to ones on his eBay shop now, but
not identical.

Inside is a toroidal **autotransformer**.

Problems:

The unit cannot possibly deliver 2000 watts -  the max continuous
rating should be no more than 500 watts. The resistance of the 240
volt winding is 5.6 ohms at room temp. Do the math.

The unit does not output 110 volts under load  -  tested with a
500 watt resistive load, it outputs only 103 volts.

The only protection for the transformer is via a fuse holder on
the back fitted with a glass fuse rated at 10A  - though the
holder is not labelled with any value.

Anyone smell smoke ??

Well, it would certainly get quite hot at its rated output, but I
don't think I'd expect smoke. If it's the same size as the one on
the website, it's reasonably large, and it only has to get rid of
50-60W.

The size of the case is irrelevant, they could shove a very small
transformer inside
you need to see the internal transformer to make such a judgement.

I'm assuming the case is as small as they can make it, simply because
that reduces the cost, and increases the potential profit.

Also, it weighs 12 kg, so it either contains a metal brick, or has a
hefty transformer.

Anyway, Phil has correctly pointed out that I've made a mistake in
calculating the heat to be dissipated given the resistance he
measured.
Yet I can't help thinking that something that heavy should be able to
achieve more than 500W. Perhaps Phil could post its exterior
dimensions - it may simply have been mislabelled.

**The mass SHOULD be a giveaway. However, I've worked on more equipment than
I care to think about, where the manufacturer (usually Chinese) has
incorporated large pieces of non-structural steel to increase the mass of
the product. I've even seen all-aluminum chassis devices, where steel has
been used to increase mass. The first time I saw this done, was with an
Onkyo (Japanese) CD player, back in the 1990s. The CD player weighed in at a
hefty 25-odd kg. More than half that mass was the result of a large piece of
steel bolted to the base plate. Without opening the player, an owner would
never realise that it was the reason for all that mass.

Seems an odd thing to do with a CD player, given that I wouldn't have
thought a consumer would expect it to be particularly heavy - and
certainly not 25kg heavy.



Mild steel plate is still less expensive than copper and laminated iron (in
the shape of a transformer).

Yes.

In this particular case it's become apparent that there's a disparity
between the mass of the example Phil has, and the mass of the 2kW model
on the website. I suppose the website could just be mis-stating the
mass, but anyone who paid attention to it on the website would notice
the difference as soon as the transformer was delivered.

Sylvia.

The average consumer would not know what weight to expect.

They also would not
know there was a problem until they tried to run it at full load, and
found that they had
an appliance not working effectively.


There is also the issue of mains frequency, especially with
transformers, ballasts etc that are made for 60hz.
Induction motors would also run slowly.

 

[Sylvia Else]

On 9/02/2011 2:29 PM, Tony the Abbott wrote:

Nothing to worry about Sylvia , "Shit happens" to the best of us!

Sadly true, though given the fuss that's being made about your
namesake's comment, some people don't seem to understand that.

Sylvia.

 

[Tony the Abbott]

Sylvia Else wrote:

On 9/02/2011 12:17 PM, Phil Allison wrote:
"Stupider than anything Else on Earth"

** Burn the witch !


The step-down tranny was supplied here in NSW by an eBay seller:

See: www.rhinotools.com.au

It is labelled as "2000W' and 240V to 110 V " plus the words "Korean
Technology".

The unit I have here is similar to ones on his eBay shop now, but
not identical.

Inside is a toroidal **autotransformer**.

Problems:

The unit cannot possibly deliver 2000 watts - the max continuous
rating should be no more than 500 watts. The resistance of the 240
volt winding is
5.6 ohms at room temp. Do the math.

The unit does not output 110 volts under load - tested with a
500 watt resistive load, it outputs only 103 volts.

The only protection for the transformer is via a fuse holder on
the back fitted with a glass fuse rated at 10A - though the
holder is not labelled
with any value.

Anyone smell smoke ??

Well, it would certainly get quite hot at its rated output, but I
don't think I'd expect smoke.


** Do the math - you stupid fucking bitch.

Try using " I squared R " maybe ......


Yes, you're right, I had a brain spasm. Just as well you've never
made a mistake.

Nothing to worry about Sylvia , "Shit happens" to the best of us!

If it's the same size as the one on the website, it's reasonably
large, and it only has to get rid of 50-60W.


** Wrong in both cases.

A buyer would have a justifiable gripe at the output voltage drop.


** The voltage dropped 7 volts ( from 110V) at 500 watts with the
input kept steady at 240V.

Do the math for 2000 watts.

I did make a comment about tap switching.

Sylvia.

 

[Chas]

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:8redjaF6omU1@mid.individual.net...

"kreed"

Interesting too how the 3kw version seems to have (hard to read) a
32amp breaker on the front panel.
Unless they are fusing the secondary with it.

**Bound to be in the secondary.

The unit I have here has the fuse fitted in the primary cos at 18 amps
nominal - the secondary side would need a fuse and fuse holder bigger
than is cheaply available.

The toroidal auto-tranny inside looks roughly made and carries no
labelling at al.

Dimensions are 120mm dia and 75mm high.

There are just three light gauge, flexible wires coming out.


.... Phil

Three wires indeed makes it an autotransformer. In my copy of AS3000,

section 4.28.4 (Autotransformers) clause 2 states: "Prohibited use.
Autotransformers shall not be used for reducing or controlling the voltage
to equipment which is liable to be handled in normal use."

Seems like the amp you are trying to repair is part of an all too common
illegal setup; be careful Phil.
--
Regards,

Chas.

(To email me, replace "xxx" with letters tango papa golf.)

 

[Bruce Varley]

"keithr" <keithr@nowhere.com.au> wrote in message
news:4d520147$1@dnews.tpgi.com.au...

On 9/02/2011 12:55 PM, Trevor Wilson wrote:

**The mass SHOULD be a giveaway. However, I've worked on more equipment
than
I care to think about, where the manufacturer (usually Chinese) has
incorporated large pieces of non-structural steel to increase the mass of
the product. I've even seen all-aluminum chassis devices, where steel has
been used to increase mass. The first time I saw this done, was with an
Onkyo (Japanese) CD player, back in the 1990s. The CD player weighed in
at a
hefty 25-odd kg. More than half that mass was the result of a large piece
of
steel bolted to the base plate. Without opening the player, an owner
would
never realise that it was the reason for all that mass.

Mild steel plate is still less expensive than copper and laminated iron
(in
the shape of a transformer).

I suppose that they could claim it to be a vibration damper. Stranger
things have been know with "HiFi" devices.

Why would they bother with an explanation? I bet the marketing instructions
were to place the unit in the hands of the prospective customer. Kaching (or
whatever the sound of a credit card sliding through a slot is....
suggestions, anyone?).

 

[Phil Allison]

"Chas"

"Phil Allison"
The unit I have here has the fuse fitted in the primary cos at 18 amps
nominal - the secondary side would need a fuse and fuse holder bigger
than is cheaply available.

The toroidal auto-tranny inside looks roughly made and carries no
labelling at al.

Dimensions are 120mm dia and 75mm high.

There are just three light gauge, flexible wires coming out.


Three wires indeed makes it an autotransformer. In my copy of AS3000,
section 4.28.4 (Autotransformers) clause 2 states: "Prohibited use.
Autotransformers shall not be used for reducing or controlling the voltage
to equipment which is liable to be handled in normal use."

** Yep - I know that section of AS3000 very well !!!!

But AS3000 is the "electrical wiring rules" - ie the electrician's bible.

4.28.4 prohibits the * INSTALLATION * of a step down, auto-transformer for
use with portable appliances.

(IIRC, ones that convert 240v to 220v are excepted from the prohibition )

AS3000 is NOT relevant to plug-in appliances sold to the public.

Seems like the amp you are trying to repair is part of an all too common
illegal setup; be careful Phil.

** Nothing illegal about it in Australia, at present.

I have personally campaigned against the open sale of auto-transformer 240V
/120 V step-downs for many years. There was a Forum column about the topic
in EA magazine in the mid 1990s that was due to my efforts.

I pointed out some of the dangers inherent in the use of such transformers
with old, US made appliances like valve radios and guitar amplifiers -
which are now pouring into this country, courtesy mostly of eBay sales.

I believe I was largely responsible for getting Jaycar to drop all but one
of the units they were selling, getting Arlec to stop importing them and
getting Farnell to drop the Arlec brand one they were selling. Unfortunately
eBay sellers appear to be a law unto themselves - even the ones operating
in this country.

It will probably take at least a couple of fatal accidents before Government
authorities step in and ban them completely.

Even that will be far too late - as there are currently many thousands in
circulation.


...... Phil

 

[Phil Allison]

"kreed"

The unit I have here weighs just under 3.8 kg including the attached
lead.

Then it's not the same as the 2kW version on the website, which weighs
12.5 kg.

** At 12.5 kg including box and assuming there is a toroidal tranny inside,
the unit must be an isolation type.



...... Phil

 

[Sylvia Else]

On 10/02/2011 9:08 AM, Phil Allison wrote:

"kreed"

The unit I have here weighs just under 3.8 kg including the attached
lead.

Then it's not the same as the 2kW version on the website, which weighs
12.5 kg.


** At 12.5 kg including box and assuming there is a toroidal tranny inside,
the unit must be an isolation type.

However, I noted that their 1kW version weighs quite a lot less than the
1kW isolating step-down transformer from Jaycar.

On the eBay web site the supplier has two 500W step down transformers.
On is an isolating transformer, the other is not. The isolating
transformer weighs 12kg, the non-isolating version only 3.4kg. Since
they've expressly identified one transformer as isolating, but none of
their other transformers that way, it seems reasonably safe to assume
that the others are autotransformers.

Sylvia.

 

[Phil Allison]

"Stupider than Anyone Else Alive"

The unit I have here weighs just under 3.8 kg including the attached
lead.

Then it's not the same as the 2kW version on the website, which weighs
12.5 kg.


** At 12.5 kg including box and assuming there is a toroidal tranny
inside,
the unit must be an isolation type.


However, I noted that their 1kW version weighs quite a lot less than the
1kW isolating step-down transformer from Jaycar.

** The Jaycar one is obviously an E-Core type - see the pic ??

An E-core will be up to double the weight of a comparable toroidal type.

An auto-transformer will be around half the weight of a comparable isolation
type.



..... Phil