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Challenge of Voltage/Digital standards differences between USA and Singapore

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x9200
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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by x9200 » Thu, 15 Sep 2016 12:00 pm

This is how I checked my 200W before saying it was an autotransformer. N was not grounded.

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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by PNGMK » Thu, 15 Sep 2016 1:24 pm

x9200 wrote:This is how I checked my 200W before saying it was an autotransformer. N was not grounded.
Was the secondary and primary connected?
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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by x9200 » Thu, 15 Sep 2016 1:32 pm

Yes. 20-70 ohms depending on the combination (In/Out/N/L). Plus probably a capacitor somewhere between N and L judging from the meter's slow response.

But I am not the OP, I am just exploring...

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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by PNGMK » Thu, 15 Sep 2016 1:53 pm

The meter's slow response may be due to the inductive affect of the TXR, similar to a capacitor.
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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by watours » Thu, 15 Sep 2016 4:02 pm

PNGMK wrote:Mmm. I bet that's an auto transformer but can't be sure without a meter. I'd recommend something like this https://www.amazon.com/ACUPWR-AUD-1500- ... ransformer
i've ordered this transformer; will test with this and post results. Thanks for your help

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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by watours » Mon, 03 Oct 2016 9:20 am

PNGMK wrote:Mmm. I bet that's an auto transformer but can't be sure without a meter. I'd recommend something like this https://www.amazon.com/ACUPWR-AUD-1500- ... ransformer
Thanks you so much for your help. I had this transformer delivered over the weekend and it fixed the problem. As it turns out, it was a grounding issue.

You are a genius; and thank you so much once again for recommending a great product.

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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by PNGMK » Mon, 03 Oct 2016 10:30 am

watours wrote:
PNGMK wrote:Mmm. I bet that's an auto transformer but can't be sure without a meter. I'd recommend something like this https://www.amazon.com/ACUPWR-AUD-1500- ... ransformer
Thanks you so much for your help. I had this transformer delivered over the weekend and it fixed the problem. As it turns out, it was a grounding issue.

You are a genius; and thank you so much once again for recommending a great product.
Well between myself and StrongEagle and the others you have a few decades of electrical engineering experience contributing. Glad to see the issue resolved.
I not lawyer/teacher/CPA.
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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by sundaymorningstaple » Mon, 03 Oct 2016 11:41 am

PNGMK, you do yourself and SE a disservice. As old as you two old coots are, I'd say a LOT of decades of experience! :lol: :lol: :P :mrgreen:

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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by PNGMK » Mon, 03 Sep 2018 12:28 pm

As a result of getting dragged into a dispute with Sim Lim type clowns on Carousell who are selling these I would remind you all that the use of Autotransformers is specifically banned in Singapore for the following cases:

No person shall use an auto-transformer to supply electricity to —
(a) a socket-outlet;
(b) a portable appliance, unless the auto-transformer is contained therein;
(c) an electric toy; or
(d) any extra-low voltage circuit.

https://sso.agc.gov.sg/SL-Rev/EA2001-RG ... vIds=pr20-

This specifically bans stand-alone autotransformers (as they are not contained in the appliance they are plugged into and of course they are fitted with a socket-outlet). This is a good thing. Unfortunately the tards at Sim Lim don't think so.
I not lawyer/teacher/CPA.
You've been arrested? Law Society of Singapore can provide referrals.
You want an International School job? School website or http://www.ISS.edu
Your rugrat needs a School? Avoid for profit schools
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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by x9200 » Mon, 03 Sep 2018 4:36 pm

PNGMK wrote: No person shall use an auto-transformer to supply electricity to —
(a) a socket-outlet;
(b) a portable appliance, unless the auto-transformer is contained therein;
(c) an electric toy; or
(d) any extra-low voltage circuit.

https://sso.agc.gov.sg/SL-Rev/EA2001-RG ... vIds=pr20-

This specifically bans stand-alone autotransformers (as they are not contained in the appliance they are plugged into and of course they are fitted with a socket-outlet). This is a good thing. Unfortunately the tards at Sim Lim don't think so.
Unfortunately "portable appliance" is not defined and:
2. In these Regulations, unless the context otherwise requires —
“appliance” means any device which uses electricity for a particular purpose but does not include a luminaire or an independent motor;

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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by PNGMK » Mon, 03 Sep 2018 7:24 pm

Yeah well appliance when I last read the Aussie regs was any none permanent electrical device. Sounds like they left a gap there.
I not lawyer/teacher/CPA.
You've been arrested? Law Society of Singapore can provide referrals.
You want an International School job? School website or http://www.ISS.edu
Your rugrat needs a School? Avoid for profit schools
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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by Strong Eagle » Mon, 03 Sep 2018 9:56 pm

PNGMK wrote:Yeah well appliance when I last read the Aussie regs was any none permanent electrical device. Sounds like they left a gap there.
It's a typical Singapore consumer screw job. Business uber all. Selling a dangerous or completely worthless product? No problem. No recourse for consumer. Consumer complains? Seller sues under libel laws, now consumer is screwed two times.

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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by PNGMK » Tue, 04 Sep 2018 12:05 am

Strong Eagle wrote:
PNGMK wrote:Yeah well appliance when I last read the Aussie regs was any none permanent electrical device. Sounds like they left a gap there.
It's a typical Singapore consumer screw job. Business uber all. Selling a dangerous or completely worthless product? No problem. No recourse for consumer. Consumer complains? Seller sues under libel laws, now consumer is screwed two times.
Honestly if I had an auto transformer blow something up I'd take it to the SCT. The act is clear in intention if not in literal language. However the most irritating thing about this shitboxes is that they trip out the ELCB's. Everytime someone complains to me that their ELCB is tripping it comes down to the one of these devil black boxes plugged in somewhere.
I not lawyer/teacher/CPA.
You've been arrested? Law Society of Singapore can provide referrals.
You want an International School job? School website or http://www.ISS.edu
Your rugrat needs a School? Avoid for profit schools
You need Tax advice? Ask a CPA
You ran away without doing NS? Shame on you!

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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by bgd » Tue, 04 Sep 2018 10:33 am

And the problem is a flawed design or just poor implementation?

How do you tell an auto transformer from an ordinary one?

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Re: Challenge of Voltage/Digital standards differences between USA and Singapore

Post by Strong Eagle » Tue, 04 Sep 2018 12:19 pm

bgd wrote:And the problem is a flawed design or just poor implementation?

How do you tell an auto transformer from an ordinary one?
It is a flawed design that is used because it is cheaper to make. In a standard transformer, there is a primary coil or winding and a secondary coil, both wound onto a common core. When alternating current flows in the primary coil, it generates a magnetic field in the core, which in turn generates a current flow in the secondary coil.

The ratio of the number of turns between the primary and secondary coils determines how much the voltage is stepped up or down. If you had 1000 turns in the primary coil, 500 turns in the secondary coil, and apply 240 volts to the primary coil, you get 120 volts in the secondary coil.

Another big, big benefit of a true transformer is that the secondary coil (and everything that is attached to it) is isolated from the primary coil, and this is the real subject of this thread. You'll see that there are no wires connecting the primary and secondary sides... therefore, if a short were to develop in the secondary coil, you're not going to get connected to the mains ground wire and get a shock. Isolation transformers used to be used in lots of electrical equipment (voltage in = voltage out) for precisely this reason... people would not get shocked if there is a short in the equipment.

Image

Now, an auto transformer only has one set of windings or coils. The primary coil is connected to the mains and like the standard transformer, let's say it has a total of 1000 turns would around a magnetic core. Now, instead of having a secondary coil, you simply tap the primary coil 500 turns down with the output wire and voila, as above you halve the voltage.

But, you'll notice that the primary and second wires are connected together. If you have a short anywhere in the coil, the possibility of being shocked by becoming grounded to the mains is possible. And even small current leaks, not enough to shock you, cause GFCI circuits to trip.

Cheaper to make and much more potential to be deadly. A hot wire anywhere in the transformer itself OR in any appliance that is plugged into it that touches ground, or the appliance handle, or anything that you might touch, has the ability to deliver a lethal shock.

Image

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