3 phase wiring anyone ?.

I have at last got a 3 phase converter. I need to change the plug on the grinder.The plug on the drill grinder - on the left below, has 3 small pins and a large pin. The plug that fits the converter (red one below) has 4 small pins and one large. The pins are labelled L1 , L2 , L3 and N in the red plug. In the grinder plug below the earth lead goes to the big pin ( no problem there) but the 2 black and one red go to pins that have no labels and there is a blue wire that is going nowhere.

Can anyone help ?.

If I understand what you have written, your new phase converter has a Female 5 way socket for it output connector.

There may be a standard connection arrangement for 3 phase on a 5 pin plug but the only way to be certain (and SAFE!) is to look in the converter manual.

Unless you know what you are doing I suggest you don't do anything until you have the information to hand.

Ian P

PS, I've just re-read your posting and realise I don't actually know which plug and wire is on which pin, so now I'm confused!

The red plug should read L1,L2,L3 these are the three phases then you should have the Earth pin ( the largest pin) and neutral N, this pin and one of the phases will give you 240 AC assuming the L1,L2,L3 have 420 to 440 volts AC across any pair of the L1 to L3. The black plug appears to have an earth pin and the three phases as Neutral N is not always used.

Martin P

To

The OP has a 4 pin plug on his grinder which looks to be correctly wired (I cannot see the yellow/green wire).

His new plug has unmarked pins, (to be fair I would assume the thick pin is earth) but connecting his two black and one red wires can only be done by guesswork. Unless the grinder has a light or a pump it not likely to be fitted with a neutral connection and his four core cable sort of confirms that.

I defer to the manual.

Ian P

I'd agree with Martin, It all depends if the machine is wired in Star or Delta. Delta just uses the 3 phases and Earth and has a 4 pin red plug, as a quick check meter the resistance between any two phases (3 readings) they should all be the same. And each phase should be open circuit to earth You could also open the cover on the motor there is usually a connection drawing on the inside of the connection cover. Note if you get the phases the wrong way the motor will turn in the opposite direction. I would personally check the other end of the cable to make sure the Neutral really doesn't go anywhere. Do be certain of what you are doing ELECTRICTY KILLS very quickly, If in doubt don't attempt it.

Lionel

Thanks chaps , heres another photo of the plug currently connected to the grinder. if it had L1 , L2 labelled like my reg plug everything would be a lot simpler. Thanks for the warnings especially in capitals , am aware that 415 volts is fairly sparky. That's why I am posting here.  There is a info sheet for the transwave converter , it is not any help.

Edited By capnahab on 19/10/2013 21:42:54

Are you saying that this picture is the plug currently fitted to your grinder? and it has a red cover?

I saw a red connector on the front of your converter so that confused me.

I have just Googled Transwave, I'm surprised, a company that I presumed has a good reputation should have better information on its website, The only info I could see that might have the details was the FAQ but I doubt the downloaded version is the same as the one Google linked me to.

If the male connector is does not have the pins identified maybe the socket on the front panel does?

Hopefully someone with the same converter will be along shortly, I'm a VFD man.

Ian P

on further investigation.

I have found the grinder wiring diagram, and transwave advice. Not sure it is any help. I think the grinder must be star , it has a 6V powered light.

Yes it is 'Star' and it does not need a neutral connection. The lighting transformer is across two phases so thats fine too.

Does not help though, as what you need are the connection details for the Transwave device.

Ian P

Green/ Yellow = Earth

Blue= Neutral (often not required unless you need to produce 240V single phase, neither delta nor star connected motors need the neutral connection to run). Modern wiring regs I've heard require the Neutral wire to be included, even if not connected at the appliance end.

Any other colours - I've seen all white, all black, sometimes labelled, sometimes not. will be L1, L2, L3. Generally the 3 L connection are interchangeable - as has already been mentioned if motor turns the wrong way, swap any 2 L connections over.

Very good advice to verify connections at the appliance end - to ensure condition of connections as well as making sure the wires go where expected.

If in doubt, call in an electrician used to working with 3 phase.

The red connector you have is a modern IEC connector for 3-phase plus neutral and earth, not surprisingly. You'd be surprised to find anything else these days. You don't have a neutral in your case so it can be left open. If you were making up an extension cable then strictly speaking you should connect all terminals through.

As you can see, there is a whole messy legacy of colour schemes but nowadays they are harmonising towards the IEC60309 std globally.

Your original connector and cable are some bizarre legacy scheme by the looks of them but assuming it worked before, the earth is clearly identifiable and the 3 phases must be the other 3 wires. So you just need to make sure you don't connect one of these to the neutral connection of your converter. And if you connect it up and the grinder goes in reverse, you can swap any 2 of the 3 phase wires.

Given that the converter seems to have an IEC socket, you should wire your mating IEC plug using the IEC convention - and identifying the empty neutral connection carefully in the process. I expect you'll find that the terminals are identified by lettering in the moulding. If not, look it up:

**LINK**

The 2 wiring diagrams show how you can connect the grinder motor in either star or delta according to the supply voltage, assuming you have a 6-wire motor. As noted, a neutral connection is not required for either.

Merry

Edited By Muzzer on 19/10/2013 23:04:34

Assuming that the original wiring has not been altered the grinder will run on a three phase 415v supply which will be supplied by your converter. There is no need to delve into star and delta connections if this is the case. The only time in "our" size motors that we need delta is when we are trying to run from a 240v three phase supply such as is usual from an inverter. If you are using a five pin plug then connect the earth wire to the large pin. Connect the three phase (live) wires to the pins marked L1 L2 L3 in any order. Ignore the N pin, this would only be required if there were single phase circuits on your machine, however with only four cores in the cable then this is obviously not the case here. Start the grinder and observe the rotation. If the machine runs backwards change over ANY TWO of the phase wires and the rotation will then be correct. Make sure the earth bonding is good. On some of the older motors this can be dodgy. Make a good strong connection to any metal part of the motor using a ring connector either crimped or better still soldered to the earth wire. It is also good practice to bond any other electrical boxes that may be on the machine.

.

Capn'

It seems probable that the Transwave is "fully wired" in accordance with IEC 60309

.... But nothing is guaranteed !!

Have a look at this Wikipedia page, wiring details at bottom-right of the table.

[note; the 60Hz reference should say 50/60Hz]

All being well, you should wire the Grinder into a 5 pin plug, ignoring Neutral.

My biggest concern, however, is the Yellow cable on the Grinder

... Yellow is usually reserved for 110 Volt "Portable Site Equipment" [which would explain the odd colours inside]

.

I would strongly recommend getting a qualified electrician to rewire the Grinder and test it on the Transwave.

MichaelG.

Under the old colour scheme three phase line colours were red, blue, and yellow, with black as neutral and green/yellow earth. Under the new scheme the three phases are brown, black and grey, with blue as neutral and green/yellow as earth.

So in the old scheme black was neutral, but is now line, and blue was line but is now neutral. Plenty of scope for wiring boo-boos.

As has been stated, for induction motors, in star or delta, the neutral line is not required.

Regards,

Andrew

.

Correction: That should read middle-right

... I've just looked again at your Red Plug, and see it is keyed at 6 o'clock.

MichaelG.

Further to the posts above. The outer sheath colour can be almost anything although I agree that in modern practice it is generally reserved for 110v site equipment. However looking at the original photo's and the wiring plate the machine must be of a certain age. The plug on the OP photo looks like a 1950/1960's type of unit which was very common (in a variety of sizes but of the same construction). There should be a metal outer ring which was threaded to allow the plug to be securely screwed to the socket. these sockets still turn up on older machinery especially T&C grinders etc. where an auxiliary motor was sometimes connected. Secondly regarding the colours the grinder is a Swiss machine (which could have been supplied through a London agent) so the colours shown on the plate will reflect Swiss practice. Most of Europe had different colour schemes for their wires. However the cable presently connected is undoubtedly a modern addition of uncertain origin.

What the OP needs to check is whether the machine is still wired for the 415v three phase supply and whether there has been any internal wiring changes since it came out of industry. Some times machines have been modified by amateurs or unscrupulous electricians and if this is the case then it should be examined by an industrial electrician used to three phase. However if the machine has been acquired straight from a factory and was in use prior to this then all should be well. It is probable that the cable shown just goes direct to an isolator on the machine. A photo of the grinder would help here.

Finally please be aware that converters such as yours do not give a true three phase supply such as would be obtained from the electricity company. They do work and will do what you want them to but it is important that they are wired in accordance with the manufacturers instructions.

We are quite nicely going round in circles now!

Lots of the previous posts are full of useful, correct, and possibly helpful information, what we still do not have (in spite of the various Wiki links) is the actual connection data from the manufacturer of the converter.

It defies my common sense for a manufacturer not to provide absolutely basic details about their product. In this day and age it is simply inexcusable. We are all expending time and effort in trying to help the OP but apart from the general warnings and good advice the rest is speculation.

My best advice would be to call on the help of someone who can examine the existing grinder wiring (to confirm it matches the printed diagram) and then with the Transwave connector data, connect it all up safely.

Ian P

Edited By Ian Phillips on 20/10/2013 11:38:10

I can't see anything wrong with what Transwave supplied, surely all the uncertainty is the unusual wiring of the grinder?

Neil