Toroidal mains Tx inrush limiter - retrofit

[N_Cook]

This 300W amp blows correct T3.15A fuses every now and then at sw on. The
owner left in the last one so I can see it is just "tired" , neat break and
2 constituent parts of fuse wire remaining.

Any issues concerning putting in an ex pc SMPS 450W, 250V land mains inrush
thermistor, unknown specs, other than 14mm diameter, 4mm wide , 1mm diam
leads, 8R cold , 1R after 20 seconds touched by soldering iron barrel. Other
than poor physical integrity of the lead "welds" to the body (like disc
ceramic cap) - will mount on small high temp board and wire into the neutral
side of the wiring, with plenty of clear air space around.

Other than zero crossing Triac sub-cicuit to delay sw off, not creating
ferrite core residual magnetism, and delayed switching on also, any other
ways around this phenomenon other than bad practise uprating of the mains
fuse? Are polyswitches used in these circumstances , ie not purely "fuse"
action or generic name for devices specific for this purpose?

 

[Phil Allison]

"Nutcase Fucking Kook"

This 300W amp.....

** WHAAATTT AAMMMPP !!!!!!!!!!!!!

You ridiculous, fucking nut case !!!

blows correct T3.15A fuses every now and then at sw on.

** Probably normal.

Use a 4 amp "slo blo" fuse.

Other than zero crossing Triac sub-cicuit to delay sw off,

** Fucking stupid.

not creating ferrite core residual magnetism,

** Toroidal mains transformers are NOT ferrite.

You ABSOLUTE DONKEY'S ASS !!!
--------------------------------------------------

and delayed switching on also,

** Zero crossing switch-on is the WORST thing you can do.

Wot a COLOSSAL MORON !!!

Are polyswitches used in these circumstances ,

** No.

They have the WRONG resistance / temp characteristic.

You fucking stupid ASS !!!!!!!



...... Phil

 

[Mike Tomlinson]

In article <imv6e9$2gm$1@dont-email.me>, N_Cook <diverse@tcp.co.uk>
writes

This 300W amp blows correct T3.15A fuses every now and then at sw on. The
owner left in the last one so I can see it is just "tired" , neat break and
2 constituent parts of fuse wire remaining.

We have a similar problem at work with cryogenic coolers, which are more
or less like a fridge - a compressor and heat exchanger. Like you say,
the fuse doesn't blow, just parts cleanly due to inrush surge at switch
on.

Any issues concerning putting in an ex pc SMPS 450W, 250V land mains inrush
thermistor, unknown specs, other than 14mm diameter, 4mm wide , 1mm diam
leads, 8R cold , 1R after 20 seconds touched by soldering iron barrel.

Don't see why not. Or a 1 ohm wirewound resistor which will dissipate
3.15W at peak, so use a 5W one. Mount it in free air, of course.

will mount on small high temp board and wire into the neutral
side of the wiring,

Why the neutral? Just curious.

Are polyswitches used in these circumstances , ie not purely "fuse"
action or generic name for devices specific for this purpose?

I would say they are unsafe for use on mains, simply because they
reconnect the current when they heal. If there is an actual fault in
the equipment rather than the inrush current blowing the fuse and
disabling the supply permanently, it could lead to a fire.

--
Mike Tomlinson

 

[Mike Tomlinson]

In article <pan.2011.03.30.13.54.22@lmao.lol.lol>, Meat Plow
<mhywattt@yahoo.com> writes

Slo Blow?

He is fitting slo blo, it's what the T in "T3.15A" means.

--
Mike Tomlinson

 

[Gareth Magennis]

"N_Cook" <diverse@tcp.co.uk> wrote in message
news:imv6e9$2gm$1@dont-email.me...

This 300W amp blows correct T3.15A fuses every now and then at sw on. The
owner left in the last one so I can see it is just "tired" , neat break
and
2 constituent parts of fuse wire remaining.

Any issues concerning putting in an ex pc SMPS 450W, 250V land mains
inrush
thermistor, unknown specs, other than 14mm diameter, 4mm wide , 1mm diam
leads, 8R cold , 1R after 20 seconds touched by soldering iron barrel.
Other
than poor physical integrity of the lead "welds" to the body (like disc
ceramic cap) - will mount on small high temp board and wire into the
neutral
side of the wiring, with plenty of clear air space around.

Other than zero crossing Triac sub-cicuit to delay sw off, not creating
ferrite core residual magnetism, and delayed switching on also, any other
ways around this phenomenon other than bad practise uprating of the mains
fuse? Are polyswitches used in these circumstances , ie not purely "fuse"
action or generic name for devices specific for this purpose?

I've had a few bits of gear for repair that just seem to have an under-rated
fuse. e.g. Mackie SR1530.
Try a T4 instead.

I even had a Marshall here that had (according to Marshall) the wrong value
fuse designed in. It was doing my head in for ages until I phoned Marshall
about it.
They sent me an uprated fuse and stickers to place on the PCB showing the
uprated value.



Gareth.

 

[N_Cook]

Mike Tomlinson <mike@jasper.org.uk> wrote in message
news:3muFuRBizykNFwrV@jasper.org.uk...

In article <imv6e9$2gm$1@dont-email.me>, N_Cook <diverse@tcp.co.uk
writes

This 300W amp blows correct T3.15A fuses every now and then at sw on. The
owner left in the last one so I can see it is just "tired" , neat break
and
2 constituent parts of fuse wire remaining.

We have a similar problem at work with cryogenic coolers, which are more
or less like a fridge - a compressor and heat exchanger. Like you say,
the fuse doesn't blow, just parts cleanly due to inrush surge at switch
on.

Any issues concerning putting in an ex pc SMPS 450W, 250V land mains
inrush
thermistor, unknown specs, other than 14mm diameter, 4mm wide , 1mm diam
leads, 8R cold , 1R after 20 seconds touched by soldering iron barrel.

Don't see why not. Or a 1 ohm wirewound resistor which will dissipate
3.15W at peak, so use a 5W one. Mount it in free air, of course.

will mount on small high temp board and wire into the neutral
side of the wiring,

Why the neutral? Just curious.

Are polyswitches used in these circumstances , ie not purely "fuse"
action or generic name for devices specific for this purpose?

I would say they are unsafe for use on mains, simply because they
reconnect the current when they heal. If there is an actual fault in
the equipment rather than the inrush current blowing the fuse and
disabling the supply permanently, it could lead to a fire.

--
Mike Tomlinson

An engineer I know with IBM Hursley has the same problem with large toroid
Tx on some research kit, he personally was not aware of the phenomenon of
random remnant magnetisation at switch off, then right/wrong polarity
mutually coupled across "adds" to the inrush current , until he asked me if
I knew.

Some more data on this thermistor , green and marked CCK but no info found
Passing DC through it , stabilizes at 2.7R with 1.2V across it so 3.2W ,
..44R and measuring 115 deg C via IR "pyrometer"

 

[N_Cook]

2.7 amp , not 2.7R

 

[Meat Plow]

On Wed, 30 Mar 2011 13:07:48 +0100, N_Cook wrote:

This 300W amp blows correct T3.15A fuses every now and then at sw on.
The owner left in the last one so I can see it is just "tired" , neat
break and 2 constituent parts of fuse wire remaining.

Slo Blow?



--
Live Fast Die Young, Leave A Pretty Corpse

 

[Mike Tomlinson]

In article <pan.2011.03.30.16.03.48@lmao.lol.lol>, Meat Plow
<mhywattt@yahoo.com> writes

Thought the T mean the size.

T for Time delay )

--
(\__/)
(='.'=)
(")_(")

 

[Meat Plow]

On Wed, 30 Mar 2011 14:56:24 +0100, Mike Tomlinson wrote:

In article <pan.2011.03.30.13.54.22@lmao.lol.lol>, Meat Plow
mhywattt@yahoo.com> writes

Slo Blow?

He is fitting slo blo, it's what the T in "T3.15A" means.

Thought the T mean the size.



--
Live Fast Die Young, Leave A Pretty Corpse

 

[Gareth Magennis]

By the way,

What's the antithesis of Occam's razor?

 

[William Sommerwerck]

Religious superstition?

 

[Meat Plow]

On Wed, 30 Mar 2011 18:52:48 +0100, Mike Tomlinson wrote:

In article <pan.2011.03.30.16.03.48@lmao.lol.lol>, Meat Plow
mhywattt@yahoo.com> writes

Thought the T mean the size.

T for Time delay )

I just thought of something. Ambient temperature does affect current
carrying capability. Maybe this has some influence on Cook's problem?
High ambient temperature over a period of time weakens the fuse material
and after current influx causes the fuse core to 'twitch' many times it
finally breaks. Not unlike a light bulb.



--
Live Fast Die Young, Leave A Pretty Corpse

 

[Phil Allison]

"Stroonz"

** Bugger off - IMBECILE

 

[Phil Allison]

"Mike Tomlinson"

We have a similar problem at work with cryogenic coolers, which are more
or less like a fridge - a compressor and heat exchanger. Like you say,
the fuse doesn't blow, just parts cleanly due to inrush surge at switch
on.

** What absolute crap !!!

The magnetic inush suge of a toroidal tranny plus filter caps charging will
easily SPLAT an undesized "slo blo" or " fast " fuse completely.

Don't see why not. Or a 1 ohm wirewound resistor which will dissipate
3.15W at peak, so use a 5W one

** ROTFL - what difference is 1 ohm gonna make ??

will mount on small high temp board and wire into the neutral


Are polyswitches used in these circumstances , ie not purely "fuse"
action or generic name for devices specific for this purpose?

I would say they are unsafe for use on mains, simply because they
reconnect the current when they heal. If there is an actual fault in
the equipment rather than the inrush current blowing the fuse and
disabling the supply permanently, it could lead to a fire.

** Polyswitches all start of with a very low resistane then go high after
some time at high current - mains voltage rated examples do not exist.



.... Phil

 

[Phil Allison]

"Nutcase fucking Kook "

An engineer I know with IBM Hursley has the same problem with large toroid
Tx on some research kit, he personally was not aware of the phenomenon of
random remnant magnetisation at switch off, then right/wrong polarity
mutually coupled across "adds" to the inrush current , until he asked me
if

** Shame you have totally mis-informed him.

I knew.

** You know absolutely NOTHING !!



..... Phil

 

[Phil Allison]

"Mike Tomlinson"

T for Time delay )

** The "T" stamp on fuses stands for the German word " Trage" = lazy.



...... Phil

 

[Stroonz]

On Mar 30, 8:22 am, "Phil Allison" <phi...@tpg.com.au> wrote:

"Nutcase Fucking Kook"


 **You ridiculous, fucking nut case  !!!

** Fucking stupid.


 **You    ABSOLUTE   DONKEY'S   ASS !!!


   ** Wot a  COLOSSAL  MORON  !!!


 **You fucking stupid ASS !!!!!!!

.....  Phil

I'm sure I'm one of the very few who haven't plonked you yet and can
actually view any of your posts (and realize that by quoting you I am
actually giving you some exposure), but I have to say that you are one
smooth talker Phil. You must be quite the hit with the ladies.

Edwin

 

[Phil Allison]

"Gareth Magennis"

What's the antithesis of Occam's razor?

** Conspiracy theories - cos they always involve many unnecessary,
unsupported and improbable assumptions.



..... Phil

 

[William Sommerwerck]

Polyswitches all start of with a very low resistance,
then go high after some time at high current --
mains-voltage rated examples do not exist.

Then what causes my bulk eraser to shut off when it overheats -- then come
back when it cools off?