I suspect this isn't possible, but I thought I'd ask just in case...

I've got a large office with a 3-phase electrical supply. But I don't
have any 3-phase equipment; I split the 3 phases to 3 x single phase
sub-mains feeding CUs on each floor.

The original building has a 3x60A supply, but that was upgraded to a
3x100A supply about five years ago. I don't think our total draw ever
exceeds 100A, so in theory we could operate from just one of the
phases.

We have regular power outages, all of which are acknowledged by UK
power networks and normally involve some sort of problem at a
substation. But strangely they don't always affect all three phases.
Hence my question:

Is there a way to convert a three-phase supply to some sort of
redundant single-phase supply? I wouldn't want something that
involves power-loss, as the 3-phase supply comes into the basement and
I don't have any easy way of getting rid of heat from there; but even
some sort of "throw the switch Igor" switchover solution would be
better than I've got at the moment when I end up losing a random floor
(and typically the CH boiler as well, which means we need to close the
office when it gets too cold).

Caecilius laid this down on his screen :
Is there a way to convert a three-phase supply to some sort of
redundant single-phase supply?

It should be possible to have (3x) interlocked contactors installed, so
that only one could be active and providing the entire supply, at
anyone time and to the entire building. That should make it possible
for it to sequence, through the phases should one drop out. I have
never seen or heard of it being done, but it is certainly practical to
do.

There would be a short interruption in the supply, during the switch
over.

Best talk to the technical department of your supplier about the
possibilities.

You would still be paying for the 3x supplies, despite only using one
at any time.

On Friday, 20 January 2017 18:33:13 UTC, Caecilius wrote:
I suspect this isn't possible, but I thought I'd ask just in case...

I've got a large office with a 3-phase electrical supply. But I don't
have any 3-phase equipment; I split the 3 phases to 3 x single phase
sub-mains feeding CUs on each floor.

The original building has a 3x60A supply, but that was upgraded to a
3x100A supply about five years ago. I don't think our total draw ever
exceeds 100A, so in theory we could operate from just one of the
phases.

We have regular power outages, all of which are acknowledged by UK
power networks and normally involve some sort of problem at a
substation. But strangely they don't always affect all three phases.
Hence my question:

Is there a way to convert a three-phase supply to some sort of
redundant single-phase supply? I wouldn't want something that
involves power-loss, as the 3-phase supply comes into the basement and
I don't have any easy way of getting rid of heat from there; but even
some sort of "throw the switch Igor" switchover solution would be
better than I've got at the moment when I end up losing a random floor
(and typically the CH boiler as well, which means we need to close the
office when it gets too cold).

Relays or rather contactors could do this easily. But do you need (to pay for) a 3 phase supply?


NT

Sounds like you need a very big changeover switch break before make three
way!
I cannot see how you could easily make this automatic or combine them
considering the phase shift involved.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Caecilius" wrote in message
...
I suspect this isn't possible, but I thought I'd ask just in case...

I've got a large office with a 3-phase electrical supply. But I don't
have any 3-phase equipment; I split the 3 phases to 3 x single phase
sub-mains feeding CUs on each floor.

The original building has a 3x60A supply, but that was upgraded to a
3x100A supply about five years ago. I don't think our total draw ever
exceeds 100A, so in theory we could operate from just one of the
phases.

We have regular power outages, all of which are acknowledged by UK
power networks and normally involve some sort of problem at a
substation. But strangely they don't always affect all three phases.
Hence my question:

Is there a way to convert a three-phase supply to some sort of
redundant single-phase supply? I wouldn't want something that
involves power-loss, as the 3-phase supply comes into the basement and
I don't have any easy way of getting rid of heat from there; but even
some sort of "throw the switch Igor" switchover solution would be
better than I've got at the moment when I end up losing a random floor
(and typically the CH boiler as well, which means we need to close the
office when it gets too cold).

It does seem strange to me that power outages are often enough to be a
problem. Maybe the infrastructure where you are needs some serious work.
Might be an idea to see how many locals this affects and get on to the power
network people to fix it properly rather than messing around with the
supply. After all in my road the phases are fed to alternate houses so if
this did happen a lot every third house would lose power, and they don't.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Harry Bloomfield" wrote in message
news
Caecilius laid this down on his screen :
Is there a way to convert a three-phase supply to some sort of
redundant single-phase supply?

It should be possible to have (3x) interlocked contactors installed, so
that only one could be active and providing the entire supply, at anyone
time and to the entire building. That should make it possible for it to
sequence, through the phases should one drop out. I have never seen or
heard of it being done, but it is certainly practical to do.

There would be a short interruption in the supply, during the switch over.

Best talk to the technical department of your supplier about the
possibilities.

You would still be paying for the 3x supplies, despite only using one at
any time.

On Friday, 20 January 2017 18:33:13 UTC, Caecilius wrote:
I suspect this isn't possible, but I thought I'd ask just in case...

I've got a large office with a 3-phase electrical supply. But I don't
have any 3-phase equipment; I split the 3 phases to 3 x single phase
sub-mains feeding CUs on each floor.

The original building has a 3x60A supply, but that was upgraded to a
3x100A supply about five years ago. I don't think our total draw ever
exceeds 100A, so in theory we could operate from just one of the
phases.

We have regular power outages, all of which are acknowledged by UK
power networks and normally involve some sort of problem at a
substation. But strangely they don't always affect all three phases.
Hence my question:

Is there a way to convert a three-phase supply to some sort of
redundant single-phase supply? I wouldn't want something that
involves power-loss, as the 3-phase supply comes into the basement and
I don't have any easy way of getting rid of heat from there; but even
some sort of "throw the switch Igor" switchover solution would be
better than I've got at the moment when I end up losing a random floor
(and typically the CH boiler as well, which means we need to close the
office when it gets too cold).

All you need is three contactors and a single pole, three way (rotary?) switch.
http://www.ebay.co.uk/bhp/rotary-switch
It would be ideal if they were also mechanically interlocked.

On Friday, 20 January 2017 18:33:13 UTC, Caecilius wrote:
I suspect this isn't possible, but I thought I'd ask just in case...

I've got a large office with a 3-phase electrical supply. But I don't
have any 3-phase equipment; I split the 3 phases to 3 x single phase
sub-mains feeding CUs on each floor.

The original building has a 3x60A supply, but that was upgraded to a
3x100A supply about five years ago. I don't think our total draw ever
exceeds 100A, so in theory we could operate from just one of the
phases.

We have regular power outages, all of which are acknowledged by UK
power networks and normally involve some sort of problem at a
substation. But strangely they don't always affect all three phases.
Hence my question:

Is there a way to convert a three-phase supply to some sort of
redundant single-phase supply? I wouldn't want something that
involves power-loss, as the 3-phase supply comes into the basement and
I don't have any easy way of getting rid of heat from there; but even
some sort of "throw the switch Igor" switchover solution would be
better than I've got at the moment when I end up losing a random floor
(and typically the CH boiler as well, which means we need to close the
office when it gets too cold).



A reversing switch for a three phase motor could probably be modified.

harry used his keyboard to write :
It would be ideal if they were also mechanically interlocked.

I would suggest both electrical and mechanical interlocking are
essential.

On 20-Jan-17 6:33 PM, Caecilius wrote:
I suspect this isn't possible, but I thought I'd ask just in case...

I've got a large office with a 3-phase electrical supply. But I don't
have any 3-phase equipment; I split the 3 phases to 3 x single phase
sub-mains feeding CUs on each floor.

The original building has a 3x60A supply, but that was upgraded to a
3x100A supply about five years ago. I don't think our total draw ever
exceeds 100A, so in theory we could operate from just one of the
phases.

We have regular power outages, all of which are acknowledged by UK
power networks and normally involve some sort of problem at a
substation. But strangely they don't always affect all three phases.
Hence my question:

Is there a way to convert a three-phase supply to some sort of
redundant single-phase supply? I wouldn't want something that
involves power-loss, as the 3-phase supply comes into the basement and
I don't have any easy way of getting rid of heat from there; but even
some sort of "throw the switch Igor" switchover solution would be
better than I've got at the moment when I end up losing a random floor
(and typically the CH boiler as well, which means we need to close the
office when it gets too cold).


How about three double throw contactors, each powered by one phase and
wired so that it passes that phase through to its associated CU when
powered, but switches to another phase when the power fails? It should
work completely automatically, with minimum down time, and they
shouldn't draw enough power to cause you heat gain problems.

If you want to allow for the possibility of two out of three phases
failing, a second contactor in series after the first and powered by the
output from the first would allow you to switch in the phase that isn't
connected to either pole of the first if both of those fail.

--
--

Colin Bignell

On Sat, 21 Jan 2017 08:45:04 -0000, "Brian Gaff"
wrote:

It does seem strange to me that power outages are often enough to be a
problem. Maybe the infrastructure where you are needs some serious work.
Might be an idea to see how many locals this affects and get on to the power
network people to fix it properly rather than messing around with the
supply. After all in my road the phases are fed to alternate houses so if
this did happen a lot every third house would lose power, and they don't.
Brian

Strange it may be, but it keeps happening. The power was out for the
best part of two days this week in two seperate outages.

The UK power networks engineer said that they'd finally worked out the
problem, which was apparently caused by two substations being linked
when no such link was shown on the map.

But we've had promises of "it's all fixed now" for a few years, and
each year there's one or two months with outages.

On Fri, 20 Jan 2017 11:48:18 -0800 (PST), wrote:

On Friday, 20 January 2017 18:33:13 UTC, Caecilius wrote:
I suspect this isn't possible, but I thought I'd ask just in case...

I've got a large office with a 3-phase electrical supply. But I don't
have any 3-phase equipment; I split the 3 phases to 3 x single phase
sub-mains feeding CUs on each floor.

The original building has a 3x60A supply, but that was upgraded to a
3x100A supply about five years ago. I don't think our total draw ever
exceeds 100A, so in theory we could operate from just one of the
phases.

We have regular power outages, all of which are acknowledged by UK
power networks and normally involve some sort of problem at a
substation. But strangely they don't always affect all three phases.
Hence my question:

Is there a way to convert a three-phase supply to some sort of
redundant single-phase supply? I wouldn't want something that
involves power-loss, as the 3-phase supply comes into the basement and
I don't have any easy way of getting rid of heat from there; but even
some sort of "throw the switch Igor" switchover solution would be
better than I've got at the moment when I end up losing a random floor
(and typically the CH boiler as well, which means we need to close the
office when it gets too cold).

Relays or rather contactors could do this easily. But do you need (to pay for) a 3 phase supply?

Probably not, but I beleive it's just a higher standing charge which
isn't a big expense for the business. And having 3-phase adds
flexibility in case I ever need more than 100A (unlikely) or want to
sell off a leasehold for one floor.

In article , Caecilius
wrote:
On Sat, 21 Jan 2017 08:45:04 -0000, "Brian Gaff"
wrote:

It does seem strange to me that power outages are often enough to be a
problem. Maybe the infrastructure where you are needs some serious work.
Might be an idea to see how many locals this affects and get on to the
power network people to fix it properly rather than messing around with
the supply. After all in my road the phases are fed to alternate houses
so if this did happen a lot every third house would lose power, and they
don't. Brian

Strange it may be, but it keeps happening. The power was out for the
best part of two days this week in two seperate outages.

The UK power networks engineer said that they'd finally worked out the
problem, which was apparently caused by two substations being linked when
no such link was shown on the map.

That could be a problem with copied maps, when the copying was done by
tracing the old one. Short links did get misses. When I was with SESEB
(getting on for 60 years ago), one customer wanted to upgrade to a 3 phase
supply - but the maps showed he had no supply at all.

--
from KT24 in Surrey, England

On Sat, 21 Jan 2017 09:56:35 +0000, Nightjar
wrote:

On 20-Jan-17 6:33 PM, Caecilius wrote:
I suspect this isn't possible, but I thought I'd ask just in case...

I've got a large office with a 3-phase electrical supply. But I don't
have any 3-phase equipment; I split the 3 phases to 3 x single phase
sub-mains feeding CUs on each floor.

The original building has a 3x60A supply, but that was upgraded to a
3x100A supply about five years ago. I don't think our total draw ever
exceeds 100A, so in theory we could operate from just one of the
phases.

We have regular power outages, all of which are acknowledged by UK
power networks and normally involve some sort of problem at a
substation. But strangely they don't always affect all three phases.
Hence my question:

Is there a way to convert a three-phase supply to some sort of
redundant single-phase supply? I wouldn't want something that
involves power-loss, as the 3-phase supply comes into the basement and
I don't have any easy way of getting rid of heat from there; but even
some sort of "throw the switch Igor" switchover solution would be
better than I've got at the moment when I end up losing a random floor
(and typically the CH boiler as well, which means we need to close the
office when it gets too cold).


How about three double throw contactors, each powered by one phase and
wired so that it passes that phase through to its associated CU when
powered, but switches to another phase when the power fails? It should
work completely automatically, with minimum down time, and they
shouldn't draw enough power to cause you heat gain problems.

If you want to allow for the possibility of two out of three phases
failing, a second contactor in series after the first and powered by the
output from the first would allow you to switch in the phase that isn't
connected to either pole of the first if both of those fail.

Thanks. That sounds like it might work. I'll sketch it out and see if
it's workable.

On 21/01/2017 08:45, Brian Gaff wrote:
It does seem strange to me that power outages are often enough to be a
problem. Maybe the infrastructure where you are needs some serious work.
Might be an idea to see how many locals this affects and get on to the power
network people to fix it properly rather than messing around with the
supply. After all in my road the phases are fed to alternate houses so if
this did happen a lot every third house would lose power, and they don't.
Brian

I currently have 3-phase issues at the shop.

1 phase is down on voltage, the 2nd which we were connected to started
browning out randomly a few years back so we were switched to the 3rd
phase which has now started breaking down giving intermittent voltage
drops.

A fault has been identified as 5m from shop but to fix it means knocking
out all the shops/flats in the row which they aren't keen on doing but
it's now been escalated to the fat-controller (I think that's who he
said) for planning apparently..

Brian Gaff submitted this idea :
Sounds like you need a very big changeover switch break before make three
way!
I cannot see how you could easily make this automatic or combine them
considering the phase shift involved.

Its no biggie to arrange, phase shift has nothing to do with it as only
a single phase is needed at any one time.

On 21/01/2017 09:56, Nightjar wrote:
On 20-Jan-17 6:33 PM, Caecilius wrote:
I suspect this isn't possible, but I thought I'd ask just in case...

I've got a large office with a 3-phase electrical supply. But I don't
have any 3-phase equipment; I split the 3 phases to 3 x single phase
sub-mains feeding CUs on each floor.

The original building has a 3x60A supply, but that was upgraded to a
3x100A supply about five years ago. I don't think our total draw ever
exceeds 100A, so in theory we could operate from just one of the
phases.

We have regular power outages, all of which are acknowledged by UK
power networks and normally involve some sort of problem at a
substation. But strangely they don't always affect all three phases.
Hence my question:

Is there a way to convert a three-phase supply to some sort of
redundant single-phase supply? I wouldn't want something that
involves power-loss, as the 3-phase supply comes into the basement and
I don't have any easy way of getting rid of heat from there; but even
some sort of "throw the switch Igor" switchover solution would be
better than I've got at the moment when I end up losing a random floor
(and typically the CH boiler as well, which means we need to close the
office when it gets too cold).


How about three double throw contactors, each powered by one phase and
wired so that it passes that phase through to its associated CU when
powered, but switches to another phase when the power fails?


I like that idea.


--
Adam

It happens that Caecilius formulated :
Thanks. That sounds like it might work. I'll sketch it out and see if
it's workable.

Be very aware that contacts can and do sometimes weld up, so mechanical
interlocking is essential.

On 22-Jan-17 1:06 PM, Harry Bloomfield wrote:
It happens that Caecilius formulated :
Thanks. That sounds like it might work. I'll sketch it out and see if
it's workable.

Be very aware that contacts can and do sometimes weld up, so mechanical
interlocking is essential.

What should be interlocked? The whole idea of the setup is that each
contactor operates separately from the others.


--
--

Colin Bignell

Nightjar wrote:

On 22-Jan-17 1:06 PM, Harry Bloomfield wrote:
It happens that Caecilius formulated :
Thanks. That sounds like it might work. I'll sketch it out and see if
it's workable.

Be very aware that contacts can and do sometimes weld up, so mechanical
interlocking is essential.

What should be interlocked? The whole idea of the setup is that each
contactor operates separately from the others.

The potential hazard is that if the main contacts on one of the
contactors weld closed, then the system closes another contactor,
it thus creates a potential phase-phase connection.

If the contactor has auxiliary contacts, so long as their state
mirrors the main contacts if they are welded, then the safety
interlocking can be electrical.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

Chris J Dixon formulated the question :
The potential hazard is that if the main contacts on one of the
contactors weld closed, then the system closes another contactor,
it thus creates a potential phase-phase connection.

If the contactor has auxiliary contacts, so long as their state
mirrors the main contacts if they are welded, then the safety
interlocking can be electrical.

Exactly! I would also want to provide some mechanical interlocking too,
to be certain it never could happen. I have come across mechanical
interlocking on star/delta motor starter systems, so I know it can be
done.

On 23-Jan-17 10:20 AM, Chris J Dixon wrote:
Nightjar wrote:

On 22-Jan-17 1:06 PM, Harry Bloomfield wrote:
It happens that Caecilius formulated :
Thanks. That sounds like it might work. I'll sketch it out and see if
it's workable.

Be very aware that contacts can and do sometimes weld up, so mechanical
interlocking is essential.

What should be interlocked? The whole idea of the setup is that each
contactor operates separately from the others.

The potential hazard is that if the main contacts on one of the
contactors weld closed, then the system closes another contactor,
it thus creates a potential phase-phase connection...

How? These are independent single pole changeover contactors, with the
common of one contactor connected to only one CU. One contactor closing
does not create a connection to the output of any other.



--
--

Colin Bignell

In article ,
Harry Bloomfield wrote:
Chris J Dixon formulated the question :
The potential hazard is that if the main contacts on one of the
contactors weld closed, then the system closes another contactor,
it thus creates a potential phase-phase connection.

If the contactor has auxiliary contacts, so long as their state
mirrors the main contacts if they are welded, then the safety
interlocking can be electrical.

Exactly! I would also want to provide some mechanical interlocking too,
to be certain it never could happen. I have come across mechanical
interlocking on star/delta motor starter systems, so I know it can be
done.

I was brought up on Castek Keys

--
from KT24 in Surrey, England

charles brought next idea :
I was brought up on Castek Keys

As was I.

On 23/01/2017 09:30, Nightjar wrote:
On 22-Jan-17 1:06 PM, Harry Bloomfield wrote:
It happens that Caecilius formulated :
Thanks. That sounds like it might work. I'll sketch it out and see if
it's workable.

Be very aware that contacts can and do sometimes weld up, so mechanical
interlocking is essential.

What should be interlocked? The whole idea of the setup is that each
contactor operates separately from the others.


+1

--
Adam

On 21/01/2017 10:50, Caecilius wrote:
On Sat, 21 Jan 2017 09:56:35 +0000, Nightjar
wrote:

On 20-Jan-17 6:33 PM, Caecilius wrote:

How about three double throw contactors, each powered by one phase and
wired so that it passes that phase through to its associated CU when
powered, but switches to another phase when the power fails? It should
work completely automatically, with minimum down time, and they
shouldn't draw enough power to cause you heat gain problems.

If you want to allow for the possibility of two out of three phases
failing, a second contactor in series after the first and powered by the
output from the first would allow you to switch in the phase that isn't
connected to either pole of the first if both of those fail.

Thanks. That sounds like it might work. I'll sketch it out and see if
it's workable.

Do short power outages cause trouble for your PCs etc or are you using UPS?



--
Adam