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Topic Title: Multifunction timers
Topic Summary: to sensitive
Created On: 16 September 2011 07:34 PM
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 16 September 2011 07:34 PM
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ArthurHall

Posts: 737
Joined: 25 July 2008

I was commissioning a board that had a multifunction timer in it, the type that is the size of a single mcb. The timer is rated as 12-240V ac or dc. The system is working at 240V ac. the timer tested ok until feild wiring was connected then it switched on permanently, investigation showed that a cable containing a live and switch wire had about 9V on the switchwire when the switch was off. Presumably due to coupling within the cable. The 9V was enough to trigger the timmer. Is this a common problem? Is there a standard solution? I am considering using a resistor to pull the switchwire down to zero or changing the timer for one dedicated to higher voltages.
Any thoughts would be appreciated.
 17 September 2011 10:27 AM
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Dave69

Posts: 447
Joined: 16 July 2011

were you using a DMM to measure the voltage?
on some cheap timers the hysterias is such that they will stay energised with silly voltages

multifunction timers are bad news at the best of times, it there is a dip switch then you can guarantee that someone will move it.

Just buy a timer with a 230V coil voltage and problem solved and i bet it wont cost more than £25, that less than an hour labour charge although it will take a good 15 mins to fit it so for about £50 the problem is solved
 17 September 2011 11:40 AM
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ArthurHall

Posts: 737
Joined: 25 July 2008

Thanks for the reply Dave
I was measuring the voltage with a DDM, I am sure that If had used a high impedance voltmeter the voltage would have been higher.
I have always been a bit dubious about equipment that claims to be all things to all people.
I have ordered new timers.
Thans again
By the way the job is not a million miles from where your picture was taken.
 17 September 2011 11:44 AM
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Dave69

Posts: 447
Joined: 16 July 2011

lol i dont know where the picture was taken, i found the pic on the net and thought it was funny

try foxtam nortronics for timers they are cheap and good
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