Inductors?*!

Nov 27, 2008 9 Replies

Anyone know a good supplier of off the shelf inductors?



I'm doing a battery charger design using a sepic converter. Got a daft spec to meet of -55C storage with 0C to 45C operation.



All the specs I've checked give -40C for storage though one from Coilcraft also gave -55C for operation??



I've tried Coiltronics, Coilcraft and Weurth.


"Raveninghorde"

** Seems to me that even a well performing PSU might be damaged by attempting to use it when its temp is -55C.

Better fit something that DISABLES the unit whenever the internal temp is to low for safe operation - like a normally open bi-metal switch that closes at 0C.

.... Phil

Not necessarily daft -- -55C storage is a pretty common mil spec requirement; it comes from (I think) high-altitude unheated cargo bays.

The only thing that surprises me is that it isn't coupled with a -40C operating spec, which is the usual MIL-SPEC system lower limit.

At any rate, there should be parts out there, although they may cost $$.

Tim Wescott Control systems and communications consulting http://www.wescottdesign.com Need to learn how to apply control theory in your embedded system? "Applied Control Theory for Embedded Systems" by Tim Wescott Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

Could be limited by the battery rating.

Best regards, Spehro Pefhany

"it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

Many military batteries charge below 0C. For example Saft do some NiCd cells which can be charged at -40C and are used in some UK batteries.

I found API Delevan do some standard inductors that will work. Unfortunately I haven't found a coupled sepic inductor yet.

Try

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I used some from them many years back that were inductors with two windings. You may have to work a little at getting a full spec sheet from them.

SNIP

Public info here:

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Section 25. 50 charge/discharge cycles. Test at -31C.

Section 17.4 states charger at 20C, battery at test temperature, max charge time 5 hours.

That's a battery for a 1980's radio.

The batteries are available on Ebay if you want to see how they are made.

Or build in a small heater to keep the internal temperature above the 'magic' number! Lucky for you, in Oz, it never gets that cold!

"Raveninghorde" "Phil Allison"

** Shame that is not any kind of data from a Ni-Cd battery maker.

You have nothing.

...... Phil

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Page 8.

Do you know _anything_ useful, or do you just cuss a lot?

Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" gives you just what it says. See details at http://www.wescottdesign.com/actfes/actfes.html

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