Adding over voltage protection to a 13.8vdc 30A power supply.

[togo54]

Can an inexpensive crowbar circuit of some sort be added to the output section the power supply?

 

[a417]

Can an inexpensive crowbar circuit of some sort be added to the output section the power supply?

Yes. What is your level of familiarity & aptitude with basic electronics?

 

[AK9R]

Wouldn't a quality power supply already have the necessary crowbar circuit?

 

[FrensicPic]

Wouldn't a quality power supply already have the necessary crowbar circuit?

My Astrons do.

 

[n5ims]

What are you trying to accomplish with your protection? It appears that the standard spec for mobile radios is 13.8 volts +/- 15% so your radio will probably be OK with the typical variations. If the issue is with a disastrous failure of your power supply that is likely already in most quality power supplies. Also, many crowbar circuits short the supply and cause it to fail due to pass transistor failures (or other similar causes) so if you simply want it to shut down if the output goes over 14v, it will be at the expense of the power supply needing major repairs.

 

[Lauri-CoyoteFrostbite]

At the expense of over simplify-ing this----

I agree that a quality power supply should have a sufficient over-voltage protective circuitry. That said, I can think of two times when switching power supply's went horribly "evil" and they took out several pieces of expensive equipment ----and why I personnaly and professionally avoid'd switching power supplies whenever possible.

That said, we had several installations that used these beasts (I apologize to those that have an attachment to these power supplies, but twice burn is, what, three times as shy, maybe ?) ---
So what I did was very simple--- I put a stepping-lock relay in series with the power output. Using a variable resistor I adjusted the relay to 'trip' at a certain voltage setting, breaking the output and latching open the relay. Exceed the voltage-- open the circuit--
And it remained locked open until the cavalry arrived.

Easy-Peasy

(And, I'll be darned, if one of those relays didn't 'save our bacon" when another 'switcher' decided to go off the reservation.)

Lauri




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[prcguy]

Over the years I've bought OVP protection boards surplus on eBay for cheap. Look for brands like Power One, Sola, Lambda, etc. These will be adjustable and simply connect to the output terminals of the power supply and if the voltage reaches your set point it will short out and crowbar the supply. Cheap and easy insurance.

What kind of power supply are you needing this for? If its a linear supply powering something expensive I can see the need as a typical 12v power supply can ramp up to 18-22volts if the pass transistors short out. I have never seen a switching power supply fail where it raises the voltage.

 

[togo54]

Thanks for the replies folks. I have the power supply that is in the link below and if you read the reviews there is several instances of the power supply running amok and supplying 28-30vdc and ruining gear. I know it's not an Astron (used to own a couple 35 amp models) but it is what I happen to own right now. The idea of adding something to the output connection of the power supply is ideally what I would like to do.

https://www.amazon.com/Audiotek-AT-PS36M-Output-30A-36A-Mobile/dp/B011J9RSWS/ref=cm_cr_arp_d_product_top?ie=UTF8