Transient Voltage Suppressor

[alka5eltzer]

Hey All,

I was hoping someone could help me.

I've designed/built a 230VAC to 30VDC power supply for a client of mine. Its rated to 2Amps constant with a Peak of 30Amps for 100ms(max).
(Its a AC-DC PSU that allows for a high inrush)
At the last minute they've asked for Transient Voltage Suppression protection... e.g. to protect their sensitive down stream equipment from spikes etc from my unit.

I've found this one on RS.. that I'm going to put in Parallel with my output terminals.. e.g. put a lead in to the + terminal and the other in to the - terminal: http://uk.rs-online.com/web/p/products/6997950/?searchTerm=699-7950
Does this look OK for my normal running spec of 30VDC, 2Amps continuous, 30Amps peak? I've chosen this as the systems built... so this is the easiest way I'm thinking.

Thanks in advance,

Alka

 

[Resqueline]

That one is a bipolar version, which seems to have worse clamping spec's than the unipolar type.
The unipolar type has a maximum clamping voltage of over 59V (@ 25A). Is that within acceptable limits for the down-stream equipment?
Also, it has a working voltage of up to almost 37V. Is that the tolerance of your supply voltage?

 

[alka5eltzer]

Hey... thanks for getting back to me...
They've said anything over 50V for more than 0.5sec will kill their equipment
So I'm thinking a 37V Clamp will do the job

Thanks

 

[Resqueline]

Ok.

There's the Working (or Stand-Off) Voltage where it conducts 1µA.
Then comes the Breakdown Voltage where it conducts only 1mA.
Finally there is the Clamping Voltage where it really conducts & protects.

A 1N6284A / 1.5KE36A has a working voltage of 30.8V, a breakdown voltage of 34.2-37.8V, and a clamping voltage of 49.9V at 30.1A.

So it seems you'll have to use this one to meet their requirements, but that also requires that your supply never exceeds a (prolonged) 30.8V output voltage.

Notice that RS is mistaken in their own spec' listing. Their "Maximum Reverse Stand-off Voltage" is actually the nominal Breakdown Voltage.
Always look in the manufacturers data sheets for the real values.

 

[alka5eltzer]

Thanks so much for your help...

Sorry... my Nominal System Voltage is 30V but its actually set to 35V DC to ride out volt drops in the 30A spikes.

Would you know of any others that would cover me?

Thanks again