Thread: Powerfeed transformer wiring diagram

Sorry Chris but 1.4.47 is about the installation & not about connected equipment
1. An electrical installation usually commences at the point of supply and finishes at a point (in wiring) but does not include portable or stationary electrical equipment connected by plug and socket-outlet (other than where a socket-outlet is used to connect sections of the fixed installation).
This part of the 'rules' is talking about an 'installation' & not about a piece of equipment, which can be a part of or connected to the installation.

1.4.48 Electrical installation, domestic.
An electrical installation in a private dwelling or that portion of an electrical installation associated solely with a flat or living unit.
1.5.5.5 Protection by electrical separation. Protection by electrical separation is intended, in an individual circuit, to prevent shock current through contact with exposed conductive parts that might be energized by a fault in the basic insulation of that circuit. Live parts of a separated circuit shall not be connected at any point to earth or to another circuit. Any protective bonding conductor associated with a separated circuit shall not be connected at any point to earth. NOTE: Clause 7.4 contains requirements for protection by electrical separation. 7.4 ELECTRICAL SEPARATION (ISOLATED SUPPLY). NOTE: The expression ‘electrical separation’ has the same meaning as ‘isolated supply’. ‘Electrical separation’ is used throughout this Clause. 7.4.1.

Scope. Several methods of protection against electric shock arising from indirect contact are recognised by Clause 1.5.5 of this Standard. These methods include that of protection by electrical separation of the supply. Protection by electrical separation is an alternative to other recognised methods and is intended, in an individual circuit, to prevent shock current through contact with exposed conductive parts that might be energized by a fault in the basic insulation of that circuit.
Protection by electrical separation shall be afforded by compliance with Clauses 7.4.2 to 7.4.4, and with— (a) Clause 7.4.5 for a supply to one item of equipment; or (b) Clause 7.4.6 for a supply to more than one item of equipment.
NOTE: Figure 7.7 provides an illustration of a separated supply to single and multiple items of equipment. 7.4.2 Source of supply.
The source supplying a separated circuit shall be— (a) an isolating transformer complying with AS/NZS 61558 so that the output is separated from the input by double insulation or equivalent; or (b) a generator output, e.g. a motor-generator set that is installed so that the output is separated from the frame of the generator; or NOTE: The fitting of an RCD, and the connection of an equipotential bonding conductor and an additional conductor to the generator output winding to ensure the correct operation of the RCD, does NOT provide the output separation required by this Clause. See AS/NZS 3010 for details. (c) an isolated inverter complying with the safety requirements of AS/NZS 4763 (Int).
2.7.2 Protection by insulation or separation. Measures to prevent danger because of faults between live parts of the electrical installation and circuits supplied at higher voltages shall consist of the following: (a) For conductors, the provision of adequate insulation screening or segregation of circuits in accordance with Clause 3.9.8.3 (b) For transformers, the provision of adequate insulation, screening or separation of windings. Transformer windings that operate at different voltages shall be insulated from one another by insulation with a specified test voltage or alternatively separated from one another by means of a conductive screen connected to the protective earthing conductor so as to ensure automatic disconnection of the supply in the event of a fault.

4.1.2 Selection and installation.
Electrical equipment shall be selected and installed to perform the following functions, or to have the following features, associated with the proper design, correct construction and safe operation of the electrical installation:
(a) Enable the electrical equipment to function properly under external influences to which it is expected to be exposed.
(b) Prevent any adverse effects that the electrical equipment might cause on the electrical installation.
(c) Operate safely when properly assembled, installed and connected to supply.
(d) Ensure that there is no danger from electric shock, fire, high temperature or physical injury in the event of reasonably expected conditions of overload, abnormal operation, fault or external influences. This Standard requires certain electrical equipment to satisfy these provisions through compliance with nominated Australian/New Zealand Standards or other relevant Standards.
The requirements of this Section 4 relate to the following: (i) External influences and environmental conditions. (ii) Adverse effects on the electrical installation and the supply. (iii) Protection against thermal effects. (iv) Methods of connection of electrical equipment. (v) Installation of socket-outlets, lighting and heating equipment. (vi) Electricity converters including UPS systems. (vii) Control, overload and overtemperature protection of motors. (viii) Transformers.

4.14 TRANSFORMERS.
4.14.1 General. Transformers shall be installed in accordance with Clauses 4.14.2 to 4.14.5. Exception: The following transformers need not comply with this Clause:
(a) An instrument transformer.
(b) An extra-low voltage transformer.
(c) A luminous discharge tube transformer.
(d) A transformer incorporated in a motor starter or other similar electrical equipment.

4.14.2 Secondary circuit.
4.14.2.1 General. The wiring and electrical equipment connected to the secondary winding of a transformer shall comply with the requirements of this Standard for extra-low, low or high voltage, as appropriate to the nominal secondary voltage. 4.14.2.2 Control and protection.
The conductors connected to the secondary windings of a transformer shall be—
(a) considered as submain or final subcircuit conductors, as appropriate; and
(b) controlled and protected in accordance with the appropriate requirements of Clauses 2.3 and 2.5.
Exception : This requirement need not apply where—
(a) the transformer secondary winding supplies only one submain or final subcircuit; and
(b) the secondary circuit conductors have a current-carrying capacity not less than the rated load current of the transformer primary winding multiplied by the ratio of the transformer primary voltage to the secondary voltage.

4.14.3.2 Other transformers.
Electrical equipment shall be earthed as required by Clause 5.4. Exception: Where the low voltage transformer output complies with the requirements of the AS/NZS 61558 series, earthing is not required on the secondary side.


In a nutshell & if this transformer is used, it (and the installation) must comply with Australian Standards. If he (or she) chooses to use other advice, it will not only go against Australian Standards but also against electrical logic. For the sake of the safety of the OP, DO NOT install any earth wiring at all!!!!
The huge problem confronting Australia (& other countries) is the amount of non-complient products being imported. Many of these products DO NOT comply to Australian Standards. These 'standards' provide a minimum level to which foreign products must achieve in order to be complient. Good luck purchasing your dishwasher etc on ebay. You may be in for a nasty surprise.

I believe you are both correct and both incorrect. To be sold in Australia it must comply with Australian standards. As it has no means of wiring to the mains, to comply technically it has to be wired by sombody qualified to do so. After a mains plug is fitted it is then up to the purchaser what he does with the thing.
So to be pedantic that thing is illegal and should not have been sold to the general public without a lead and plug and probably insulation tested. I am concerned with the idea of fitting an earth to the plug, from what I see the machine may be double insulated. The lid is also a concern, it seems to be clipped on, not screwed. If this is so, over the years the hinges may rust or oxides in paint could create a diode effect and like an old cats whisker radio, then transmit TVI So if it doesnt have one, whack a small selftap screw in an out the way place on the side through the lid and base.

elkangorito
Are you talking to me? or is there another Stewart(Stuart) around?
Transformer type is an issue.
The secondary windings of an isolation transformer have 0 potential to ground/earth.
Not all transforner designs provide isolation.
You picture even says "isolating transformer"(although the drawing of the load confuses me lol)
You could use a 240V- 240V isolation tranformer, running a machine on it with no need to earth.

Having said that I see no point in "carriying the earth through to the earth pin on the 110V socket"

As long as the OP isn't selling said equipment as "new" and it plugs in, I believe he can do what he likes.This is not to say he should do what he likes, just that the standards do not apply(for private use). I can't see anything in your last post that talks about "connected equipment" only "installation"

Stuart

Originally Posted by Stustoys

Having said that I see no point in "carriying the earth through to the earth pin on the 110V socket"

As long as the OP isn't selling said equipment as "new" and it plugs in, I believe he can do what he likes.This is not to say he should do what he likes, just that the standards do not apply(for private use). I can't see anything in your last post that talks about "connected equipment" only "installation"

Stuart,

I think we are pretty much in agreement. I note that we might have a difference of opinion on the earth at the 110Vac outlet. And I agree, that by and large it'll make little difference.

I suppose my view is that the outlet is a 3-pin version and not a 2-pin version, therefore, I'd be inclined to wire the earth as there is provision for it. Someone else may assume it is connected because it is a 3-pin outlet. Also, I think (but could be wrong?) this style of outlet will be earthed anyway as the earth is connected to the metal bracket on the socket, which is connected to the case, which is (hopefully) connected to the earth on the supply lead. The earth might as well be connected properly rather than through the case metal work.

Even though there maybe "no point", there is no harm either.

Now you blokes have me confused on how to wire up my 415-24V transformer.. I was just going to wire L1 and L2 to the transformer on one side with a 0.5A fuse connected to one of the legs, and the other side the 24V goes to the control circuit.

Originally Posted by .RC.

Now you blokes have me confused on how to wire up my 415-24V transformer.. I was just going to wire L1 and L2 to the transformer on one side with a 0.5A fuse connected to one of the legs, and the other side the 24V goes to the control circuit.

All the above discussion is applicable - you are just using a different voltage transformer. As you have a 415V single phase primary, you just connect it between two active phases rather than an active and neutral.

415V input - 24V output transformers are commonly used to power work/task lights from 3-phase supply that hasn't got a neutral connected. (The motors in industrial machines are usually 3-phase delta).

When you look into any forum you will find it sways from the pedantic rule stickler to the "sheel be right mate" For electrical, look at the post above, you wont go far wrong.

Originally Posted by steran50

HI,
I just Wired it up and the House Fuse Blew straight away.
.

Why did the fuse blow?

Regards
Ray

I= V/R I is current, so your voltage was too high or your resistance was too low. So something was wrong with "it" or the way you wired it.

Originally Posted by chrisp

Even though there maybe "no point", there is no harm either.

Yeap, that about covers it.
Stuart

Originally Posted by RayG

Why did the fuse blow?

Regards
Ray

HI ALL,
The House Fuse Blew, because the Unit has a Short. I picked the Unit up from the Auto Electrician on Friday. The Auto Elec did an Ohms Test when I dropped it off and said it appears to be Crook. The Auto Elec got another Guy who is better Qualified to Test the Unit and the Result was it has a Short. The other Guy also had Said I hadn't done anything wrong ie My Wiring was Correct. Although I thought I was right on how to Wire it up,I checked with an Industrial Electrician. The Industrial Electrician Confirmed that My idea on how to Wire the Unit up was Correct. The Wiring Method that I used was Incoming Neutral to '0' and Incoming Active to '240' and Incoming Earth linking to 110V Earth.

*One Note here which I have previously mentioned about the Earth. When I lifted the Cover off the Unit (which does have provision for a securing screw - meaning cover gets earthed properly) I could see the remains of the Incoming 240 Volt Earth that had been Cut off the Units pre existing Power Cord. The remains of the incoming Earth was quite clearly affixed at the same point with the same screw as the 110 Volt Earth of which comes from the 110 Volt Output Socket.. *Another Note for Interest the Output Socket is a USA one.

Quote 'Generally speaking, Auto Electricians may not have a clue about Domestic Electrical Wiring (because they don't need to know anything about it).' end quote Yes, generally speaking in some cases where they are only Working on Cars, Motorbikes, Trucks etc that is True. In Australia a lot of Auto Electricians Work on Fridges, Freezers, Electric Motors, Power Tools, Welders etc and in that sense, they do need to know something about Domestic and Industrial Electrics.

As for all the Electrical Rules, Yes they are there for a good reason. I don't Claim to be an Domestic or Industrial Electrician nor do I Claim to have a Sound knowledge of Domestic or Industrial Electrics. I can Say though that I do know a fair bit about it. Being an Outboard Mechanic, I can say that I have very Sound Knowledge of both 12 Volt Voltages and Voltages on Outboards (Outboard Ignition Systems use higher Voltages than any other Engine). I had never dealt with this sort of Stepdown Transformer before, which is why I asked for Assistance. The Transformer is used for and was to be used for a Power Feed (variable electric motor) on a Mill Drill in a Domestic Enviroment. The Unit was going to be Plugged into a Power Point and not hard Wired. (used a Plug in Device).

Now back to the Unit in Question. The Unit was Advertised on Ebay as being New and Unused. Align 240v -110v Transformer supplied by Hare & forbes (eBay item 130486955249 end time 22-Feb-11 16:23:30 AEDST) : Industrial I was aware that the Unit did not have a Power lead on it, I thought that maybe the Earlier Units did not have leads fitted. How did I I know it was an Earlier Unit - I have not seen that Hare and Forbes Sticker that is Stuck on the Units Cover for a Long Time. As for the Unit being New, No it is not New. There is Paintwork off the back of the Unit from where it has been Mounted on a Wall or Machine. On the Inside of the Unit I can Clearly see the Marks from the Screws (in the Screw Keyhole Slots) that were used to Fasten the Unit to a Wall or Machine.

I have already been in Contact with the Seller about Possible Negative Feedback. He has got back to Me wanting the Unit back as ASAP to have it Tested and either Replace it or A Refund. I have not mentiond about it being not New as yet, but will do in My Response to His Email.

Originally Posted by steran50

The House Fuse Blew, because the Unit has a Short. I picked the Unit up from the Auto Electrician on Friday. The Auto Elec did an Ohms Test when I dropped it off and said it appears to be Crook. The Auto Elec got another Guy who is better Qualified to Test the Unit and the Result was it has a Short.

Stewart,

Thanks for the update. Just a question regarding the short to clarify the situation - is it something to do with the transformer itself?

HI,
Yes, The Transformer is Crook there is No Resistance - Analogue Multi-Meter Swings straight over to the Right from any given Point but not from earth. Have been offline a bit due to Computer Trouble. Computer is still not 100 %.

Originally Posted by steran50

HI,
Yes, The Transformer is Crook there is No Resistance - Analogue Multi-Meter Swings straight over to the Right from any given Point but not from earth. Have been offline a bit due to Computer Trouble. Computer is still not 100 %.

Well, let's hope the seller does the right thing by you and you at least get your money back, but that still leaves you looking for a 240 to 110 transformer.

Just a minor point, ( for future reference ) you can't, as a general rule, test for shorted turns on a transformer with a multimeter, but in this case I guess it's a dead short, so it's detectable.

Regards
Ray