Motor rating plate

[333rocky333]

A few motor plates the all suggest the delta is the 230 and Star 400?

Whilst Im on it, can I ask another couple of basic questions

If we were to connect a single phase motor we could us either a 230v or 400 V coil, as the 230v could pull in the contacts, with a neutral to the coil? and a neutral ran through the spare contactor (5)

If it were a DOL (without neutral for the coil A!-A2) connecting a 3 phase motor, the coil would HAVE to be 400V and the coil would connect between Two of the phases.

images awaiting moderation.....

Yes correct, though 400v control circuits may be more for an industrial environment where often 3 phase is used and no N present at the machinery.
Likely operated by higher skilled people

230v control often found and as you say would need a N present.

Not sure what you mean by "Neutral ran through the spare contactor (5)"
Sometimes you need to be carefull switching N with the 3 phase, ideally you need to break last and make first the Neutral, this is not possible with a basic starter and reason lots of stuff is just 3 Pole
.
You will also find 24volt control circuits these are often used when there's lots of devices, buttons etc for control and safety of users.
Advantage no hazardous voltage in areas accessible to workers

Coils are interchangeable nowadays and come in a wide range of voltages

 

[JohnW2]

Definitely!

Fair enough. However, if those two sources were all we had to go by, we obviously would not know which (if either) was correct. Also, 'yours' doesn't give any indication of the relative prevalence of the 220V, 380V and 440V 3-phase supplies, so it would not have been impossible that 380V (which is what 'mine' said) was by far the most common. However, those two sources are not all we have, since ..

For my "day job" my employer builds & ships educational equipment to many countries, including the Philippines. Our standard config is 220V single phase & 220V L-L 3 phase for the Philippines.

... and I obviously cannot argue with your employer, who presumably is selling equipment which can be used by the buyers! However, as a matter of interest, what proportion of the total is represented by the "220V L-L 3-phase"?

That's a pretty bizarre one, and certainly not something I've ever come across. What is the thinking behind that? What is the phase difference between the two main phases?

We are spoilt here in the UK in that we've all grown up with a system where is just one LV service 230/400V 40Hz. Thats just not the case in alot of Countries - there are many possible services depending upon the region.

I suppose that one can call it 'spoilt', but it seems eminently sensible

However, no-one has yet asked my most recent question. Bearing in mind that 'star' seems to be the only configuration for 230/400V mentioned on the rating plates we've been seeing, why would anyone use star to run (as opposed to start) a motor being fed with 230/400V?

Kind Regards, John

 

[333rocky333]

I

I think that statement could confuse people, since it could be read as meaning that it requires 'more power to get it mowing' than would be available in delta configuration - whereas the fact is, of course, that there is about 3 times more power when used 'delta'. As I understand it (as always, perhaps incorrectly!), the reason for "star-delta starters' is that large motoirs can draw very high starting currents, so better to start them, 'at lower power, in star, before switching to delta 'when they have got going'.

That's a more in depth reason☺
I just recall remembering, when we done the bottling plants, being told, don't try and start big motors in Delta,.
As you imply , i quess the high currents blew fuses and two phased the motors causing damage.

 

[JohnW2]

That's a more in depth reason☺

Well, as I said, I think it probably is 'the' reason.

I just recall remembering, when we done the bottling plants, being told, don't try and start big motors in Delta,. As you imply , i quess the high currents blew fuses and two phased the motors causing damage.

Quite. As I said, if it were a question of the amount of 'brute force' needed to 'get the motor going', it would be better to start it in delta. However, as we've both said, there will be much greater starting currents in delta, which could have 'consequences', hence the reason for not doing it (with 'big' motors). That's always been my understanding, anyway.

Kind Regards, John