Regarding High Current Tripping

[sabu31]

Dear All,

I need to use a tripping mechanism for AC current typically in range of 150 to 200A. I tried one SSR which had rating of 200A. However, even when around 120A flows through it, the SSR heat sink (along with fan) temperature rises to around 70Degree Celsisus.
Are there any SSR for use in continuous operation in this current range. Or can we parallel the SSR for the same. Also I would like to know if there any triacs which have similar rating. I checked mouse, but could find triace up to 88A.

What are the other low cost options for achieving this. Thanking you.

 

[KlausST]

Hi,

However, even when around 120A flows through it, the SSR heat sink (along with fan) temperature rises to around 70Degree Celsisus.

I guess the datasheet gives informations what power dissipation to expect. And then it´s on you to calculate and use a suitable heatsink.
Another guess: the SSR works with Triac / SCR thus the power dissipation calcualtion is rather complicated when the current waveform is non sinusoidal.
And ... paralleling of Triacs / SCRs does not reduce power disspation that much (compared to transistors)
And ... a Triac / SCR can not be switched OFF immediately ... it stays ON until zero cross of current.

And there we are... specifiactions and requirements:
* What is your operating voltage?
* How fast do you need to switch OFF?
* What is the load?
* any other information we need to know?
* what does "low cost" mean for you?

As first idea .. I´d use a relay.

Mosfets or IGBTs could be a benefit ... depening on the requirements and specifications...

Klaus