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  #1   Report Post  
nick
 
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Default anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit

Hi all

I'm hoping somebody knows more about this than I do.

We have a standard fluorescent light that has stopped working.
I have replaced the tube and starter with known working ones and
still light doesnt work.

With the light switch on, I measured 240 volts going into the Choke,
but zero volts coming out of the choke.

From this I assumed the Choke was faulty (is this a correct
assumption)
Also I took out the Choke and no current passes through it using an
Ohmmeter/
Multimeter connected across the 2 terminals.
Again I figured the Choke must be faulty / open circuit from this (is
this
correct?)

I then replaced the 40W Choke with a similar thing from an old fitting
called a Ballast hoping this would fix the light.
It didnt - although for some unknown reason the light did come on for
about 5 minutes then died after putting the outer light casing back on
for the night????
Now when I switch on, there is a very dim light just at both ends of
the tube.

By the way the ballast I put in is 65W (is this important when the old
unit
was a 40W choke. The light tubes are 40W.)

I am still left wondering if the Choke is faulty, and if it is then
why isnt
the replacement ballast not working. (Yes I did connect it up the same
way)

Thanks for any help and advice
(Im surprised this isnt more of a common problem - I couldnt find
anyone
experiencing this same problem)

Regards
Nick
  #2   Report Post  
Frisket
 
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Default anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit


"nick" wrote in message
om...
Hi all

I'm hoping somebody knows more about this than I do.

We have a standard fluorescent light that has stopped working.
I have replaced the tube and starter with known working ones and
still light doesnt work.

With the light switch on, I measured 240 volts going into the Choke,
but zero volts coming out of the choke.

From this I assumed the Choke was faulty (is this a correct
assumption)


Very likely.


I then replaced the 40W Choke with a similar thing from an old fitting
called a Ballast hoping this would fix the light.


Same thing, different name

It didnt - although for some unknown reason the light did come on for
about 5 minutes then died after putting the outer light casing back on
for the night????
Now when I switch on, there is a very dim light just at both ends of
the tube.

By the way the ballast I put in is 65W (is this important when the old
unit
was a 40W choke. The light tubes are 40W.)



I am still left wondering if the Choke is faulty, and if it is then
why isnt
the replacement ballast not working. (Yes I did connect it up the same
way)

I think the old choke has probably bitten the dust. Someone else is
doubtless an expert on these things but I always try to replace like for
like when swapping components - 65w is considerably more than 40w - maybe
the 1st firing killed your starter.

Thanks for any help and advice
(Im surprised this isnt more of a common problem - I couldnt find
anyone
experiencing this same problem)

Regards
Nick



  #3   Report Post  
BigWallop
 
Posts: n/a
Default anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit


"nick" wrote in message
om...
Hi all

I'm hoping somebody knows more about this than I do.

We have a standard fluorescent light that has stopped working.
I have replaced the tube and starter with known working ones and
still light doesnt work.


Stop there. If you've replaced both the tube and starter lamp and it still
ain't working, then the fitting itself is at fault and needs replaced. You
don't have to go any further with more tests and the like. You need a new
fitting.


With the light switch on, I measured 240 volts going into the Choke,
but zero volts coming out of the choke.

From this I assumed the Choke was faulty (is this a correct
assumption)
Also I took out the Choke and no current passes through it using an
Ohmmeter/
Multimeter connected across the 2 terminals.
Again I figured the Choke must be faulty / open circuit from this (is
this
correct?)

I then replaced the 40W Choke with a similar thing from an old fitting
called a Ballast hoping this would fix the light.
It didnt - although for some unknown reason the light did come on for
about 5 minutes then died after putting the outer light casing back on
for the night????
Now when I switch on, there is a very dim light just at both ends of
the tube.

By the way the ballast I put in is 65W (is this important when the old
unit
was a 40W choke. The light tubes are 40W.)

I am still left wondering if the Choke is faulty, and if it is then
why isnt
the replacement ballast not working. (Yes I did connect it up the same
way)

Thanks for any help and advice
(Im surprised this isnt more of a common problem - I couldnt find
anyone
experiencing this same problem)

Regards
Nick



---
BigWallop

http://basecuritysystems.no-ip.com

Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.495 / Virus Database: 294 - Release Date: 30/06/03


  #4   Report Post  
impvan
 
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Default anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit

Yes, the choke's knackered.

You haven't come across anyone else with the problem as chokes don't
often fail like this. They normally develop shorted turns and melt,
then go bang.
  #5   Report Post  
Chris Oates
 
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Default anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit


"impvan" wrote in message
m...
Yes, the choke's knackered.

You haven't come across anyone else with the problem as chokes don't
often fail like this. They normally develop shorted turns and melt,
then go bang.


and stink like hell




  #6   Report Post  
Terry
 
Posts: n/a
Default anyone know how to diagnose a faulty Choke / Ballast in fluorescentlight circuit

Chris Oates wrote:

"impvan" wrote in message
m...
Yes, the choke's knackered.

You haven't come across anyone else with the problem as chokes don't
often fail like this. They normally develop shorted turns and melt,
then go bang.


and stink like hell


Not sure if this would apply to your 230 volt versions but I have
usually found that a faulty "ballast/transformer" (as we call our
115 volt and various other voltage versions) will have an open
primary/mains input winding. However ours, unless they are very
old like 40 to 50 years, do not use 'starters'.
ballasts for the last 40 or so years have incorporated a thermal
cut out in case the ballasts overheats and AFIK it does not reset
thus protecting against shorts and potential fires. And yes, some
of them do ooze black 'goo'. Which these days is said to be not
of the 'cancer causing' variety. i.e. PCBs!
Some appliances do use just a series choke in a very simple
inductive circuit to fire the fluorescent tube/s.
Idea anyway.
  #7   Report Post  
Chris Oates
 
Posts: n/a
Default anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit


"Terry" wrote in message
...
Not sure if this would apply to your 230 volt versions but I have
usually found that a faulty "ballast/transformer" (as we call our
115 volt and various other voltage versions) will have an open
primary/mains input winding. However ours, unless they are very
old like 40 to 50 years, do not use 'starters'.
ballasts for the last 40 or so years have incorporated a thermal
cut out in case the ballasts overheats and AFIK it does not reset
thus protecting against shorts and potential fires. And yes, some
of them do ooze black 'goo'. Which these days is said to be not
of the 'cancer causing' variety. i.e. PCBs!
Some appliances do use just a series choke in a very simple
inductive circuit to fire the fluorescent tube/s.
Idea anyway.


series choke here, no thermal protection
not suitable as raceway even though they
are used that way.


  #8   Report Post  
BigWallop
 
Posts: n/a
Default anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit


"Chris Oates" wrote in message
...

"impvan" wrote in message
m...
Yes, the choke's knackered.

You haven't come across anyone else with the problem as chokes don't
often fail like this. They normally develop shorted turns and melt,
then go bang.


and stink like hell



You better believe it.


---
BigWallop

http://basecuritysystems.no-ip.com

Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.495 / Virus Database: 294 - Release Date: 30/06/03


  #9   Report Post  
The Natural Philosopher
 
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Default anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit

Terry wrote:

Chris Oates wrote:

"impvan" wrote in message
. com...

Yes, the choke's knackered.

You haven't come across anyone else with the problem as chokes don't
often fail like this. They normally develop shorted turns and melt,
then go bang.

and stink like hell


Not sure if this would apply to your 230 volt versions



No, it doesn't. We have enough strike voltage without needing a step-up
transformer.

but I have
usually found that a faulty "ballast/transformer" (as we call our
115 volt and various other voltage versions) will have an open
primary/mains input winding. However ours, unless they are very
old like 40 to 50 years, do not use 'starters'.
ballasts for the last 40 or so years have incorporated a thermal
cut out in case the ballasts overheats and AFIK it does not reset
thus protecting against shorts and potential fires. And yes, some
of them do ooze black 'goo'. Which these days is said to be not
of the 'cancer causing' variety. i.e. PCBs!
Some appliances do use just a series choke in a very simple
inductive circuit to fire the fluorescent tube/s.
Idea anyway.



  #10   Report Post  
Dave Plowman
 
Posts: n/a
Default anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit

In article ,
BigWallop wrote:
We have a standard fluorescent light that has stopped working.
I have replaced the tube and starter with known working ones and
still light doesnt work.


Stop there. If you've replaced both the tube and starter lamp and it
still ain't working, then the fitting itself is at fault and needs
replaced. You don't have to go any further with more tests and the
like. You need a new fitting.


Hmm. It might be one of several, and or no longer available. What's wrong
with fixing it?

I've put electronic ballasts in old fittings before now to retain the
appearance.

--
*Go the extra mile. It makes your boss look like an incompetent slacker *

Dave Plowman London SW 12
RIP Acorn


  #11   Report Post  
nick
 
Posts: n/a
Default anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit

Thanks for the advice

Seems that it is the choke then (still not sure why the
replacement 65W ballast didnt work though - unless thats busted
aswell)

I will find out how much a replacement choke costs before probably buying
a complete new fitting.

Much Obliged
Nick
  #12   Report Post  
Dave Plowman
 
Posts: n/a
Default anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit

In article ,
nick wrote:
I will find out how much a replacement choke costs before probably buying
a complete new fitting.


A 40w choke costs 3.85 + vat from TLC.

--
*If tennis elbow is painful, imagine suffering with tennis balls *

Dave Plowman London SW 12
RIP Acorn
  #13   Report Post  
Dave Plowman
 
Posts: n/a
Default anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit

In article ,
N. Thornton wrote:
Choke = ballast.


Not really. A ballast refers to an 'all in one' control unit. A choke is
simply an inductor.

--
*If all is not lost, where the hell is it?

Dave Plowman London SW 12
RIP Acorn
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