Bench power/testing?

cjensen · Post by **cjensen** » Fri Nov 09, 2007 2:48 pm

I am slowly starting to think more about electrical stuff for the RV, and since I am a supreme novice when it comes to things electric, I am going to ask some dumb questions.

The first one being about bench power or bench testing. I'd like to turn stuff on before it goes in the airplane, and I have this charger/output station that I've used for years for everything from jump starts to powering my hand held in the cockpit of my Cherokee (didn't have a 12V output).

Is it safe to use this for bench powering avionics like the A210 I just got? Are there any precautions? Just clamp the proper polarity, and go?

dons · Post by **dons** » Fri Nov 09, 2007 3:19 pm

It certainly wouldn't bother me using that as a power supply. I would make sure it wasn't plugged into the wall charging at the same time. There are so many ways those devices could be built, I would feel better about the charging circuit not being energized while connected to avionics. In addition, if you want to feel a bit safer, put a fuse (or low voltage circuit breaker) in series with the power going to your equipment under test.

When I test things on the bench I normally use a power supply with current limiting to be extra safe, but that's just because I have a few that I designed/built more than 30 years ago (ouch, I'm getting old). When I tested my electric elevator trim, I just hooked it up to a 12 volt battery with clip leads.

svanarts · Post by **svanarts** » Fri Nov 09, 2007 4:10 pm

I bought a 12VDC bench power supply from Chicken Shack just for this
purpose. But you would probably be fine with the device you mentioned.

On 11/9/07, RB Lists - Avionics <support@rivetbangers.com> wrote:
> I am slowly starting to think more about electrical stuff for the RV, and
> since I am a supreme novice when it comes to things electric, I am going to
> ask some dumb questions.
>
> The first one being about bench power or bench testing. I'd like to turn
> stuff on before it goes in the airplane, and I have this charger/output
> station that I've used for years for everything from jump starts to powering
> my hand held in the cockpit of my Cherokee (didn't have a 12V output).
>
>
>
> Is it safe to use this for bench powering avionics like the A210 I just got?
> Are there any precautions? Just clamp the proper polarity, and go?
>
>

> --
> Chad Jensen
> N755CB RV-7 Tip up
> SB Fuselage
> Jabilycosubarazdaklin!
> www.chadandbrittne.com/RV-7.htm
> _________________________________________________________
> rivetbangers.com - Discussion topic
> http://www.rivetbangers.com/cgi-php/for ... 1515#21515

--
Scott VanArtsdalen

Walk in wisdom toward them who are without, redeeming the time.
Colossians 4:5
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captain_john · Post by **captain_john** » Fri Nov 09, 2007 9:08 pm

Ummmm, yah...

12 volts is 12 volts.

...so long as it is DC, anyways.

Me? I am waiting for the panel to be juiced up and "alive" before I do any real testing.

I expect everything to work straight outta the gate. Call me naive' if you will. It is just the way I work.

CJ

Post by **Spike** » Sat Nov 10, 2007 7:00 pm

Chad,

You need to be very careful turning on things like comms and transponders, anything that transmits. If a transmitter attempts to transmit without the proper cabling / antenna you can destroy the device. Id be very cautious with what you power up.

Check with some pros first.

- Spike

tmbg · Post by **tmbg** » Sun Nov 11, 2007 2:32 am

spike's right.... it is possible to blow the output transistors in a transmitter if there's no load, but it's not TERRIBLY likely. For testing your com, just make sure you don't key it and there's no problem. You likely won't have it wired up enough to key it, so it's probably no biggie. Same thing with a transponder, just keep it on standby and shouldn't be a problem.

captain_john · Post by **captain_john** » Sun Nov 11, 2007 7:53 am

A very reputable source (Thermos) told me that the final amplifier used for transmitting can be toasted if the 50 ohm load (that the antenna normally applies) is not present or is somehow c omprimised.

I guess what we are all saying is, make sure the antenna lead is not ghetto rigged and comes off while bench testing the unit. If so, you may get toasted finals.

ALSO, the chance for mis-wiring can happen anytime the unit is wired. If you are doing this procedure twice, you are doubling your odds of screwing it up!

Not that it is hard, but the unit is new. The odds are VERY LOW that anything is wrong with it. Leave it alone and do something else!

DON'T FIDDLE WITH IT!

CJ

RV7Factory · Post by **RV7Factory** » Wed Dec 05, 2007 5:32 pm

Couldn't you just make your own 12V power supply?

http://www.tc.umn.edu/~beck0778/powersupply.html

Would this work?

cjensen · Post by **cjensen** » Wed Dec 05, 2007 5:35 pm

That's pretty cool! A lot of work working with something I know nothing about, but it's cool!!

Womack2005 · Post by **Womack2005** » Thu Dec 06, 2007 7:59 am

As mentioned above: Don't key the comm unloaded!

Also, when looking at a power supply, a battery is best. But if you use a supply just make sure it has minimal ripple. Switching supplies are best. But if you do have ripple, you can get rid of it with a capacitor.

Here is a good one:

http://www.mpja.com/prodinfo.asp?number=16020+PS

Also, never fire up your weather radar in the hanger (if ya still wanna have kids)

JOHN TIPTON · Post by **JOHN TIPTON** » Thu Dec 06, 2007 9:09 am

I think we discussed this not so long ago - how about a simple CB power supply, (search e-bay: there are plenty around) they are even 13.8 volts

captain_john · Post by **captain_john** » Fri Dec 07, 2007 7:56 pm

John, Yup!

If I were to toast my newly purchased radio, I would do it with a cheap power supply too!

No need to get all fancy about it!

CJ

RV7Factory · Post by **RV7Factory** » Sat Dec 08, 2007 2:11 am

OK guys, hook me up. I don't have a battery sitting around, so instead of buying one, I would like to pick up a DC power supply.

I want to do things like testing my strobes and position lights, and yes, eventually fire up the panel (long way off). I've looked on eBay, but what specs should I be looking to buy? How many Amps, Watts, etc.?

On a related note, do you think the coverted computer ps I linked to above would work for the time being (for navs and strobes).

I'll look throught the archives, maybe this has already been answered.

Thanks!

JOHN TIPTON · Post by **JOHN TIPTON** » Sat Dec 08, 2007 7:21 am

John, Yup!

If I were to toast my newly purchased radio, I would do it with a cheap power supply too!

No need to get all fancy about it!

CJ
_________________
N357JS Registered!
RV-7 Fuselage

So expensive power supply is OK !!!

smithhb · Post by **smithhb** » Sat Dec 08, 2007 9:38 am

Just do what I did... Go to your nearest Radio Shack and be done with it.

12V / 15A

Wicked Stick · Post by **Wicked Stick** » Sat Dec 08, 2007 7:44 pm

I see they have the 3 amp unit for about $50.00 and the 15 amp box goes for about $85.00 +tax.

Radio Shack's website had a couple of reviews on them.

RV7Factory · Post by **RV7Factory** » Sat Dec 08, 2007 8:13 pm

Perfect, thanks Bret!

cnpeters · Post by **cnpeters** » Sun Dec 09, 2007 1:20 pm

Chad et al - I bought a Pyramid PS-21KX power supply. It outputs at the alternator's rough output of 13.8v. Plus, I wanted one that has enough amperage to power a whole panel - this one has 20amp capacity. It costs around $60 on the net. I also like this as I can view the load if not known per the meter. I did this with the HID taxi and landing lights I made. I wouldn't use your charger shown without seeing detailed specs on its output.

Wicked Stick · Post by **Wicked Stick** » Sun Dec 09, 2007 9:03 pm

cnpeters wrote:Chad et al - I bought a Pyramid PS-21KX power supply. It outputs at the alternator's rough output of 13.8v. Plus, I wanted one that has enough amperage to power a whole panel - this one has 20amp capacity. It costs around $60 on the net. I also like this as I can view the load if not known per the meter. I did this with the HID taxi and landing lights I made. I wouldn't use your charger shown without seeing detailed specs on its output.

18 amps continuous and having the meter to see the load is a def plus.
The price is right there with radio shack's too. Seems like a good buy.

cjensen · Post by **cjensen** » Mon Dec 10, 2007 10:05 am

Good deal Carl! I'll be talking to you about that little piece of equipment!

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