inrush current limiters

[colden]

Help, i'm looking for a keystone CL-60 thermistor. They have them at Digikey but with the minimum order rules and being a Canadian, I'd be looking at a bundle of $$$$. This device is to limit the start up current to my Leach superamp. If anyone knows where I can get one, please fill me in.
Cheers----

 

[Peter Daniel]

I can send you CL-70. It has slightly higher impedance, but will work fine in this application, I used them.

 

[colden]

Cl 70

sounds great--email me please at colin_wood@telus.net

 

[markp]

Has anyone every tried the NTC inrush current limiter devices? They are supposed to pass a certain amount of current and clamp down on higher currents. Sure would be an easy solution if it works.

 

[fdegrove]

Hi,

Has anyone every tried the NTC inrush current limiter devices? They are supposed to pass a certain amount of current and clamp down on higher currents. Sure would be an easy solution if it works.

Yup. I use them all the time, both on the primary and on the secondary side.

Cheers,

 

[Bryan]

So then, if using the NTC on the primary side, what specs does one look at when choosing the specific device? Is it fair to assume that the resistance of such a device reaches a minimum when passing a specific amount of current?

For example, to use this device on a power tranny primary, which is rated as 150 mA, which device would be optimal, and why?

Thanks for entertaining the curiosity.

Bryan

 

[sam9]

How does it work.

How do you use a thermistor such as the CL-xx to limit inrush??

I've seen other methods, but thi one is new to me. Is there a schematic to which I can be directed? Or which can be posted.

 

[markp]

Use the unit that will pass the maximum steady state current you are expecting to see. If you have a 6 amp transformer use the 6 amp unit. Just put it inline on the hot lead to the transformer input.

 

[fdegrove]

Hi,

So then, if using the NTC on the primary side, what specs does one look at when choosing the specific device? Is it fair to assume that the resistance of such a device reaches a minimum when passing a specific amount of current?

Bryan,

Sorry, what I use are PTCs not NTCs for overcurrent protection.

Epcos


Cheers,

 

[sam9]

Sound too simple.

What is steady state current with a power amp? I thinking of the dynamic demands of musical sources; a lot of the simple an amp is loafing and then there is a sudden demand that takes you to clipping. Do you select for max current assuming the caps are fully charged already? This seems like the right way. Any comments.

If these work they sure beat some elaborate schememes I've seen involving inductors, relay and whatnot.