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ICL blown out

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spec

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if anybody could help i am trying to find a new one. the one in the pic is bad. it is from a Vero PK 120 Tri-Volt power supply. thank you.

View attachment 100957
Hy dwerdermann,

Welcome to ETO. I see you are from the US. Which state: care to put it next to 'Location' on your user page so that your location displays in the window on the left of your posts. This helps us to better target our replies to you.

As far as I can tell a Taiwanese company 'Uppermost' manufacture the thermister: http://www.uei.com.tw/eabout.htm

I think the NTC thermister (surge protector/inrush current limiter) that you show is part number, N15SP015-5, which is part of the SP (surge protector) range, as listed in this document: http://img.ozdisan.com/ETicaret_Dosya/6645_1794883.pdf

Even if the exact part cannot be obtained a similar part should be available from other manufacturers: Little Fuse, Murata, Epcos (TDK).
spec
 
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spec

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At a guess the ST15004C from U S Sensor would be a replacement thermistor, subject to further investigation: http://www.ussensor.com/inrush-current-limiting-power-thermistors
But not stocked

(update 2016_08_29)
This TDK inrush limiter should do the job though (in stock): http://www.digikey.com/product-detail/en/epcos-tdk/B57238S160M/495-3059-ND/652139

This inrush limiter is 16 Ohm, 4A, 80S, rather than 15 Ohm, 4A, 100S but it will still be fine in your circuit.
(the 15 Ohm version is not in stock)
spec
 
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vtech

Active Member
Without a diagram, first determine if it is MOV (varistor) OR NTC (thermistor). Similar packaging but completely different devices.
How can you tell?
NTC (thermistor) is always wired in series with the AC circuit. A low value, heat sensitive resistor that normally takes the brunt of the current while providing an inrush cushion.
Therefore it may fail after certain hours of operation. Specially if it is under-rated or more problems down the circuit.
MOV on the other hand is used as a surge protector and always wired in parallel between the two AC lines. It acts like an open switch and will only crow bar(fail) if it sees a potential higher that its ratings
Also, in majority of cases, MOV failure will blow the main fuse while NTC failure may not.
I agree with spec and it appears to be a NTC . It does appear to follow the numbering system used by ITG, UTI among others. --N15SP015
However, not a bad idea to verify how it is wired on the PCB.

Vtech
 

Tony Stewart

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if anybody could help i am trying to find a new one. the one in the pic is bad. it is from a Vero PK 120 Tri-Volt power supply. thank you.
You can choose one to protect your PSU but more important , is why did it fail?
Did you line exceed the 240Vac input? Did it lose power as a result?

I suspect it is a 1.5A ICL which wore out from frequent power cycling or internal cooling issue.
Rapid power cycling would increase the current surge.

http://www.digikey.com/product-search/en/circuit-protection/inrush-current-limiters-icl/656273?k=&pkeyword=&pv679=12&FV=fff4000a,fff80391&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=500
 
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spec

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You can choose one to protect your PSU but more important , is why did it fail?
Of course. We can take it that the OP has figured that.

I suspect it is a 1.5A ICL which wore out from frequent power cycling or internal cooling issue.
Rapid power cycling would increase the current surge.
???

It's a 15 Ohm @ 25 deg C, 3A operating NTC thermistor, as stated in the references of my posts.

spec
 

dwerdermann

New Member
I can say that there is frequent power cycling and cooling issues. The ps and the computer it is plugged into is in a very harsh industrial foundry environment. Since like 1996. The "computer" is part of a system that pours molten iron into a mold. It uses laser sighting to look for the pour hole in the sand mold. Then, this computer talks to a Plc that moves the molten iron vessel to its target. Just vfds and squirrel cage motors. It's called 'Selcom'.
 

Tony Stewart

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It turns out to be a 15mm 15Ω ICL Datasheet



Other variables for current limit may be chosen here for an equivalent

http://www.digikey.com/product-search/en/circuit-protection/inrush-current-limiters-icl/656273?k=&pkeyword=&pv678=22&FV=fff4000a,fff80391&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=500


The datasheet indicates 101 second between power cycle (time constant) then it is a 4A inrush current limiter. Dissipating 3.5W probably has an operating temp rise near it's limit of 170'C.

Frequent hot cycles accelerate aging rate. The ICL should not be in too hot an environment.
 
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Tony Stewart

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Of course. We can take it that the OP has figured that.

???

It's a 15 Ohm @ 25 deg C, 3A operating NTC thermistor, as stated in the references of my posts.

spec
The datasheet that matches the part is 4A rated.
Your TDK suggested replacement is 3A rated.

**edit **
This would be used to charge up a large AC bridge cap of unknown value. The surge instead of 100's of amps depends on the initial,phase voltage at turn on and is basically Vp_ac/15Ω, which can be a lot more than 4A but 4A is the max current it can handle before failure steady state when it reaches 170'C to regulate its NTC controlled resistance. If not allowed to cool 2 minutes between usage, the next things that fail sooner are the diode bridge and big e-cap.

So the NTC or ICL (inrush current limiter ) is a critical part for circuit protection of charge control. I would go with the highest Amp rating of 15-20 Ohm part, which drops down to < 1Ω when hot.
 
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dwerdermann

New Member
Thank you!

Btw. The 5mm onboard fuse is 3.25a. Ceramic

no its 3.15a. ceramic slow blow. we use the ceramics on relay output cards. by and large
 
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Tony Stewart

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I Would recommend the one with a 4A rating 100 seconds time constant to match original.

and change title from MOV to ICL blown out....
 

dwerdermann

New Member
Thanks for changing the title and thanks for all the info. This is probably the best forum on this matter. Guess I got lucky. I like this forum too... @ Plcs.net
 

dwerdermann

New Member
I can say that there is lot less than 2 minutes between power cycles. Thanks once again. I'll try to let you guys know what happens, in the end.
 
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