S
sparky steve
Hello I hope nobody minds a little story from Western Australia.
Where I work is a newish factory building it is about 5 years old and I do not know who specified the electricals but i guess it was an overpriced electrical consultant who as a race I have a fairly low opinion!
The have installed Clipsal CBus control all over the place and that defeats me. CBus is brilliant as a computer control system but in factories where the lights are on all day you do not really need computer control.
Some areas are set up to maintain constant light depending on the level of ambient light which is very clever. But.. it is driving Mercury Vapour lamps which have a pretty short bulb life and we spend a lot of time in half darkness waiting for restrikes!
In another area we have 1000W MV highbays up in the roof, they are fed by a 20A breaker for each phase which is switched by a contactor driven by the CBus controller. The contactors are the Merlin Gerin enclosed ones that look very pretty and rated at 25A which is all very sunny and wholesome, except, the 25A is for AC1 pure resistive. Technically Lights are AC5a but AC3 is easier to find a value for, it seems to me and the 25A merlin units actually are 8A AC3 which, when you find you have about 13A per phase normal run current, is a little alarming.
These contactors have a history of failure and one went the other day I dismantled it and what I found frankly is a worry I am suggesting to my boss that we use a 25A AC3 contactors to replace these units. Anyone in industrial should always pay attention to the current ratings and the load in question. No good using AC1 current with an AC3 load!
Sparky Steve
Where I work is a newish factory building it is about 5 years old and I do not know who specified the electricals but i guess it was an overpriced electrical consultant who as a race I have a fairly low opinion!
The have installed Clipsal CBus control all over the place and that defeats me. CBus is brilliant as a computer control system but in factories where the lights are on all day you do not really need computer control.
Some areas are set up to maintain constant light depending on the level of ambient light which is very clever. But.. it is driving Mercury Vapour lamps which have a pretty short bulb life and we spend a lot of time in half darkness waiting for restrikes!
In another area we have 1000W MV highbays up in the roof, they are fed by a 20A breaker for each phase which is switched by a contactor driven by the CBus controller. The contactors are the Merlin Gerin enclosed ones that look very pretty and rated at 25A which is all very sunny and wholesome, except, the 25A is for AC1 pure resistive. Technically Lights are AC5a but AC3 is easier to find a value for, it seems to me and the 25A merlin units actually are 8A AC3 which, when you find you have about 13A per phase normal run current, is a little alarming.
These contactors have a history of failure and one went the other day I dismantled it and what I found frankly is a worry I am suggesting to my boss that we use a 25A AC3 contactors to replace these units. Anyone in industrial should always pay attention to the current ratings and the load in question. No good using AC1 current with an AC3 load!
Sparky Steve
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