UPS? Ought to be standby generator, but then again no one ever checks
them or the Pikey's will have the diesel away..
On 06/08/2026 21:09, tony sayer wrote:
UPS? Ought to be standby generator, but then again no one ever checks
them or the Pikey's will have the diesel away..
I heard of a number of failures of maintained supplies because it had
never been properly tested. Some people would try to limit the effect on
the users by running up the diesel to speed then switching half the load >onto it then after things settle down, switching the other half onto it.
The same applies to UPS maintained supplies.
We were instructed to test by just pulling the main breaker, there would
be a short break but that happens a time when it does not cause much >disruption and when there are people around to sort out any problems.
On Fri, 7 Aug 2026 06:40:50 +0100, JMB99 <mb@nospam.net> wrote:
On 06/08/2026 21:09, tony sayer wrote:
UPS? Ought to be standby generator, but then again no one ever checks
them or the Pikey's will have the diesel away..
I heard of a number of failures of maintained supplies because it had
never been properly tested. Some people would try to limit the effect on >>the users by running up the diesel to speed then switching half the load >>onto it then after things settle down, switching the other half onto it.
The same applies to UPS maintained supplies.
We were instructed to test by just pulling the main breaker, there would
be a short break but that happens a time when it does not cause much >>disruption and when there are people around to sort out any problems.
In this case, the power cut to the ROC only lasted 90 seconds, but it
caused 24 hours of disruption.
In message <hqib7l9gqrc03ohfud8giie5tprrlrf6ai@4ax.com>, at 13:11:47 on
Fri, 7 Aug 2026, Recliner <recliner.usenet@gmail.com> remarked:
On Fri, 7 Aug 2026 06:40:50 +0100, JMB99 <mb@nospam.net> wrote:
On 06/08/2026 21:09, tony sayer wrote:
UPS? Ought to be standby generator, but then again no one ever checks
them or the Pikey's will have the diesel away..
I heard of a number of failures of maintained supplies because it had
never been properly tested. Some people would try to limit the effect on >>> the users by running up the diesel to speed then switching half the load >>> onto it then after things settle down, switching the other half onto it. >>>
The same applies to UPS maintained supplies.
We were instructed to test by just pulling the main breaker, there would >>> be a short break but that happens a time when it does not cause much
disruption and when there are people around to sort out any problems.
In this case, the power cut to the ROC only lasted 90 seconds, but it
caused 24 hours of disruption.
Echoes of when there was a National Grid low-frequency event, and lots
of AC trains decided to sulk, and took many hours to re-boot.
On 06/08/2026 21:09, tony sayer wrote:
UPS? Ought to be standby generator, but then again no one ever checks
them or the Pikey's will have the diesel away..
I heard of a number of failures of maintained supplies because it had
never been properly tested. Some people would try to limit the effect on
the users by running up the diesel to speed then switching half the load >onto it then after things settle down, switching the other half onto it.
Had that at work in the 1980s. Brand spanking new computer system
installed in a room with a "clean" supply fed from the main incomer
and a "dirty" one off the local fuse, both via a changeover switch.
Each time that the diesel generator was tested, the computer went off.
We eventually worked out that because nobody had bothered to label the changeover switch, the "normal" position it had been left in at
installation was from the local room supply that would be interrupted
when the diesel was tested. 10 seconds with a felt tip pen cured it.
In message <hqib7l9gqrc03ohfud8giie5tprrlrf6ai@4ax.com>, at 13:11:47 on
Fri, 7 Aug 2026, Recliner <recliner.usenet@gmail.com> remarked:
On Fri, 7 Aug 2026 06:40:50 +0100, JMB99 <mb@nospam.net> wrote:
On 06/08/2026 21:09, tony sayer wrote:
UPS? Ought to be standby generator, but then again no one ever checks
them or the Pikey's will have the diesel away..
I heard of a number of failures of maintained supplies because it had >>>never been properly tested. Some people would try to limit the effect on >>>the users by running up the diesel to speed then switching half the load >>>onto it then after things settle down, switching the other half onto it.
The same applies to UPS maintained supplies.
We were instructed to test by just pulling the main breaker, there would >>>be a short break but that happens a time when it does not cause much >>>disruption and when there are people around to sort out any problems.
In this case, the power cut to the ROC only lasted 90 seconds, but it >>caused 24 hours of disruption.
Echoes of when there was a National Grid low-frequency event, and lots
of AC trains decided to sulk, and took many hours to re-boot.
On 09/08/2026 02:30, Charles Ellson wrote:
Had that at work in the 1980s. Brand spanking new computer system
installed in a room with a "clean" supply fed from the main incomer
and a "dirty" one off the local fuse, both via a changeover switch.
Each time that the diesel generator was tested, the computer went off.
We eventually worked out that because nobody had bothered to label the
changeover switch, the "normal" position it had been left in at
installation was from the local room supply that would be interrupted
when the diesel was tested. 10 seconds with a felt tip pen cured it.
Sounds very much as if no one had ever tested by turning of the supply
at the main breaker.
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