Un-usual 3 phase problem

[needasparks]

Just read Archy's thread, it's given me an idea but I need to know the total loading and the switch rating of the meter.

I'm all ears.

total of eight heaters 3kw a pop spread across the phases (slightly out) with one phase on standard 100amp coin meter. operating a 100amp 240v 3 pole contactor cutting feed side to ryb to DB.

 

[needasparks]

EEEK!... you would create a star point on the neutral bar and send 415v through all the system.

No because it controls a contactor not the load.

 

[needasparks]

Interesting problem!

After banging my head against the wall for a while, how about this, put the meter on the neutral associated with these 3 phases only??? Probably needs more thought.

edit

probably a very dangerous way of doing it!
The heaters would still be live when the meter disconnects the neutral.

The neutral would be phase shifted on the load anyway

 

[Knobhead]

I drew it out and then chucked it in a computerised waste bin.

I’ve got to admit it’s one of the more interesting problems.

Now if we had a budget of £*** then it could be fun.

 

[needasparks]

I drew it out and then chucked it in a computerised waste bin.

I’ve got to admit it’s one of the more interesting problems.

Now if we had a budget of £*** then it could be fun.

PMSL, i got to agree. Have i found an un-answerable question. Gonna sleep on it and check back later.

 

[Nolnoc]

Was the coin meter ever actually ever monitoring all three phases.From what I can make of it it wasn't.Maybe I've lost the plot.Please keep us informed,interested in this one.

 

[needasparks]

Was the coin meter ever actually ever monitoring all three phases.From what I can make of it it wasn't.Maybe I've lost the plot.Please keep us informed,interested in this one.

No was only ever on one phase, been in service for about 30 years. was always assumed all heaters would be used so tarrif on coin meter was turned up taking into account other phases so money put in covered the cost used, all was happy all this time then people using the heaters started turning off some of the heaters and come across the fact their money did not run out when certain ones were turned off. What i should have explained and i missed in my first post was that this is a hall used by the public for hire, hence it being a coin meter as no other form of payment would be any good. Different people use the hall for different things so now not all heaters in all locations are used. its only recently the penny dropped so to speak on the problem that the electricity used over the last 12 months was totally different from the takings of the meter. It was so obvious but no-one picked up on it well apart from some regular userswho i guess have been keeping quiet on finding it out.

 

[Darkwood]

There is a way but its not cheap and you will have to build it all from scratch and programme it, you need a multi-function energy meter, plc, coin slot with reconition system. Your energy over three phase is monitored and run through a plc which you write the software to convert the coins input into killowatts allowed which then will countdown but first because this is just a idea i would talk to technical of the link supplied and see if the meter can give said info to plc http://docs-europe.electrocomponents.com/webdocs/0e36/0900766b80e364a3.pdf

I use plc's in machine control so cant see why this cant be done it all depends on the meter giving a readable output for energy used to plc.
The link shows a monitoring system that can control outputs such as contactor looks like you get software with it but as i said a chat with technical will be needed first explain what you need etc and let them do the thinking.

 

[Silly Sausage]

EEEK!... you would create a star point on the neutral bar and send 415v through all the system.

Haha...hence my comment of more thought required!

 

[ipf]

Was the coin meter ever actually ever monitoring all three phases.From what I can make of it it wasn't.Maybe I've lost the plot.Please keep us informed,interested in this one.

Started reading not long ago and I was thinking along the same lines. Head scratching. Fair assumption that all the heaters would be used all the time. Depending on for how long, how much more has been paid than should have been, prior to someone having an economical brainwave?

 

[Knobhead]

This is something you should read http://www.ofgem.gov.uk/Consumers/Pages/Resaleofgasandelectricity.aspx

 

[darcy]

Pondering this one...

 

[Darkwood]

Well its time to pop to the beerhole and im going in the mind that ive given a solution albiet expensive, i can now have a drink and peace of mind that i havent been beaten by what seemed a simple question to start with
arty:

 

[needasparks]

That was the only option Darkwood i thought would be open to me, other than using 3 separate meters. There is always the option of multiple coin timers on contactors but then you run the risk of overpaying. However the heaters can be split into 4 areas so limits turning off locally. Time could then be calculated by the KW per coin.

IPF, it has only ever been measuring 6kw (2 x heaters) so cant over charge. only ever under charged when any are turned off.

Biggest job i have is trying to explain the options available to the client, if we are struggling to get our heads round it this then they need to sit down for a while.

 

[ipf]

Fair enough. But something is wrong. Maybe it was the easiest way out without causing problems? For a while at least!