3 phase wiring anyone ?.

Neil..quite

Neil

The existing 4 pin plug on the grinder looks quite normal wiring to me, (ground and three phases), OK colours are not 'standard' but presumably that is how it was wired and working.

If I understood the OP, the Transwave connector has unmarked pins and the Transwave data did not help.

Ian P

Good stuff , I am still alive and the grinder is running the correct way , tho needs much adjustment. Thanks for those of you who encouraged me to do it myself, it has saved me no end of time and expense.

just for info. The grinder is at least from 1986. It is fairly impervious to opening and examining, and even of it were I would need to know my way around a multimeter ( and I don't) to work out what was happening as a black wire looks like a black wire.

I've got a converter because the 3 phase quote was £11,000 ( for those who don't like them. ).

Well done !! Always glad to hear when someone has succeeded. I was lucky because I got three phase put in for free, all I had to do was dig a trench across my front garden the electric board did the rest all for no charge. (This was in the days before privatisation) I don't think SWMBO would appreciate a bill for £11,000 !!!

Hi Ian,

the first post stated:

> 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.

Once we grasped that the OP's description omited to include the large pin (Earth), there was no ambiguity about the connector supplied with the converter, especially as the paperwork from Transwave explains just what L1, L2 and L3 are. It also explains that L1 and N can be used for 240V accessories.

Neil

Neil

Re-read the first post again. Your description 'grasped' is a good one, but its not something I did at the time!

Thanks for pointing it out. At least the OP has it all working now.

Ian P

Hi

I need to do what the above original poster needed to do which is basically connect a three phase machine to a 5 pin plug. I understand about not having a neutral but my wire form the machine is a 3 core armoured wire (red blue yellow) which was disconnected straight off the large on off rotary switch on the factory wall. I am assuming the armour was the earth in this case but to connect this to a 5 pin socket is my only hope really going to be replacing the armoured cable for a 4 core flexi cable so I can get the earth connected to the plug?

Thanks

Buffer

Edited By Buffer on 14/06/2021 19:33:45

Hi Buffer

First you need to decide what amperage your machine needs, this will determine the plug type and new flexible cable size. What is the current required by your machine on full load ?

It is not a good idea to use the armoured cable by fitting a plug, if you want to use it for protection terminate it in an isolator and use a flexible lead fitted with a suitable plug to connect to your converter, however the SWA may not provide a suitable resistance to use as a cpc (circuit protective conductor (Earth)) and comply with regulations.

Emgee

Edited By Emgee on 14/06/2021 19:58:37

I would replace the armoured cable with a 3 core and earth flexible cable. I think using the armour wire as earth is not recommended these days although properly installed it is a very good earth. Armoured cable is not supposed to be used for a movable application and is likely to suffer early failure. The plugs should have the pins marked but often they are just moulded with no contrasting highlight so are difficult to read.

Mike

Thanks for the swift replies. I think you've ajust confirmed what I was thinking so that's great.

Emgee its 2.1 kw for all 3 motors running which as far as I can tell isn't that much, based on the fact I have a 2kw electric heater. I'm out walking thr dog at the moment so cant easily look stuff up.

Buffer

Do you have spindle, table feed and suds motors, if so total all motor FLC from the motor plates, also length of cable effects cable size required.

Emgee

Yes that's right three motors and it's going to be less than 10m because my garage is 9.5m long.

I have just removed my little mitsubishi inverter and 13a plug from the motor for my tool grinder and converted the motor to Star. I was about to put my 16A plug onto the lead when it suddenly occurred to me that I now have no on off switch and no fuse! I would be relying on switching the converter on and off to operate the machine. Which isn't any good.

As I have never used 3 phase 415V before only 240V 3 phase what do you generally do about a fuse, it's not in the plug anymore?

How have some of you done this and what sort of on off switches are you getting for your machines?

Thanks

Buffer

Buffer

Normal practice with an inverter is to connect it directly to the motor and use the inverter controls. Either directly off the box or via buttons on a remote pendant. Although its extra expense pendant control is generally preferable because the inverter box can be placed safely out of harms way. Pendant boxes are generally smaller and easier to mount in the most convenient place for easy operation. Common commercial practice is to mount pendant boxes on moveable arms for even better access.

The inverter parameters should be set to match the motor so a fuse isn't needed.

With a hard wired inverter you do need a disconnector in the line able to take a padlock for secure lock off when working on things. I like this lever operated type :-

**LINK**

https://www.electroreplacement.com/erl-4-pole-isolator-switch-20a-35a-45a-63a-max-415v-ip66

because the red lever on a yellow background makes it easy to see whether things are switched on or not. Even if right across the workshop. I got mine from Lewden as type ISO-35 but they seem harder to find and more costly. For single phase outlets I use the grey bodied versions.

I'm greatly in favour of being able to easily see exactly what is, or isn't, powered up and potentially able to run and consider the common round knob disconnector as an accident waiting to happen!

For main supply input you can't beat the old style grey metal cabinet with a chrome lever that goes "CLUNK" when operated. Appropriate sound effects build confidence.

Clive

Edited By Clive Foster on 17/06/2021 18:07:39

Edited By Clive Foster on 17/06/2021 18:08:28

You could fit a DOL starter in the line to the grinder and rely on the protective device fitted within the converter or if the motor is fractional horse power you could use an mcb in an enclosure to provide switching and current overload protection.

I advertised here some months ago an ideal solution for you, a Telemecanique Fused switch with motor overload and stop/start buttons on the cover, IP65 rated. Still have 2 units left if you're interested.

Clive

Thanks for the reply. Yes I have been using an Inverter and the grinder was switched by the inverter and the 13 A plug had a fuse but that has all gone now as I have a workshop 3 phase converter. It was only after I started to put the 16A 3 phase plug on the motor lead to the grinder that I realised there is now no fuse or on off switch! So I was wondering what people do about this.

Emgee

Thanks I will keep that in mind. Can you PM me the details.