Toroidal mains Tx inrush limiter - retrofit

In article , N_Cook writes

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.

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.

Why the neutral? Just curious.

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

Slo Blow?

--
Live Fast Die Young, Leave A Pretty Corpse

In article , Meat Plow writes

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

--
Mike Tomlinson

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.

and

inrush

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"

2.7 amp , not 2.7R

Thought the T mean the size.

--
Live Fast Die Young, Leave A Pretty Corpse

In article , Meat Plow writes

T for Time delay :o)

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

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

By the way,

What's the antithesis of Occam's razor?

Religious superstition?

"Stroonz"

** Bugger off - IMBECILE

"Mike Tomlinson"

** 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.

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

"Mike Tomlinson"

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

..... Phil

"Gareth Magennis"

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

.... Phil

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

Hehe... I think you and I are the only two folk who can see your posts Phil. Don't worry, I won't plonk you. There is precious little else on the web that's as interesting as you. Make sure you come up with a real zinger for me!!!!

Edwin

bob

"boob errs = Google Monkey "

** Wot a load of utterly irrelevant, mindless drivel.

Musta been written by a marketing puke.

..... Phil