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3 Phase Time Switch


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8 replies to this topic

#1 brewmet

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Posted 25 March 2011 - 08:32 AM

Hi,
I'm just about to install a 3 phase 8 Way DB that will feed 4 x 9Kw 3 phase immersion elements.
The customer has asked for each element to be fitted with a time switch.
The elements will be controlled by a 20amp Rotary Isolation switch.
What can I install, and where should it be installed?
The elements are due to be hard wired, but I suppose I could fit a 32amp plug onto the tail?
Cheers

Dave

#2 benji

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Posted 25 March 2011 - 10:48 AM

I would get a sarel/rital hinged enclosure approx 300x200x150 fit a dinrail in it and mount a 4pole isolator ,3pole contactor ,timer & a 2amp mcb (for control circuit) on front of enclosure mount isolator handle to lock the enclosure lid when on,mount enclosure adjacent heater/tank fit kopex from enclosure to heater and wire it up.You must use heat resisting cable correctly sized from heater to contactor also for control of contactor via heater thermostat,most 3phase immersion heaters have two thermostat pockets for inclusion of a safety high limit stat,you could also put a couple of indicator lights on the front of enclosure.The above would cost approx £140 each

#3 Andyâ„¢

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Posted 25 March 2011 - 12:15 PM

will each have in individual timer or 1 timer for the lot?

#4 kme

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Posted 25 March 2011 - 06:16 PM

Nice post Benji. Scoob awarded mate :):)

#5 Evans Electric

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Posted 25 March 2011 - 08:57 PM

Excellent post from Benji :Applaud

#6 brewmet

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Posted 25 March 2011 - 09:09 PM

Hi Benji,

Thanks for the advice.

Dave

#7 brewmet

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Posted 01 May 2011 - 09:38 PM

Hi all.
OK, the plan has changed!
There can be a single timeswitch to control power from main isolator to DB.
What is available out there, that can handle this load?
Cheers

Dave
PS
It also needs to have a manual override to stich the timeswitch off!

#8 Sidewinder

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Posted 01 May 2011 - 09:59 PM

As per Benji above, and fit an on / off push button into the door?
That way you have to reset it in the event of a power fail.
IF it MUST come back on after a power fail, then use a latching switch in the door?
Just wire the controls for the 4 contactors in parallel feeding each one from the DB?
Put a local isolator at each immersion if the control panel is remote?
Really you need to be able to isolate the panel, though with 4 circuits scrap that!...

Use one timer fed from another db way to run 4 seperate boards similar to the suggestion above?
You could put the timer control in a small enclosure in an accesible area, or even use a domestic timer as you would be just controlling the contactors, then use a box like the suggestion by Benji for each heater just leaving out the timer?


Not really now sure what you are trying to achieve!

It feels tooo late now, don;t know why very tired all of a sudden!

#9 Evans Electric

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Posted 01 May 2011 - 11:00 PM

You need something like a 63 A TP contactor , also need to be rated AC23 .




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