Opinion on a DC power supply

12vdc is not very common in the controls world, and the size should be determined after you know what devices it will need to power.

5 amps of 12 volts DC should be enough to light pilot lights, a few handfuls of smallish relays and have some left over.

What is this PLC trainer that you have???
12 vdc is fairly common for A/V stuff like video cameras but seldom used by PLCs.

It's a assortment of goodies that was discarded/donated like a 12vdc CO2 gas valve from a Miller welding suitcase, 110db horn (12vdc) a couple ice cube relay, that's about it. (I guess I could use my 12v power supply that I took from and old computer and use plumbers tape to hold it into place) but my other relays and devices are 24vdc or IEC 110vac 3 phase contactors,and most of the stuff is on DIN rail. One famous man said "now you know the rest of the story". Let's not forget the PLC AB 1000 and a smart relay.

OK!!! ???
Here's a good source for inexpensive power supplies.
http://www.trcelectronics.com/

Great source mendonsy thanks...but how many watts decision,decision!!

Well, it sounds like you don't really know what your power requirement is so the next approach is to get the most power per dollar. The RS-150-12 is 150 watts (12.5 amps) for under $30.

One advantage of having a 12 VDC power supply is that you could use discarded or junk automotive devices such as lights, window motors, temperature sensors for your PLC trainer. That is if you are a junker and hate to spend money for things that you can get cheap.

Of course you could buy a used or surplus 13 VDC car battery charger with 3 different charging (voltage) levels, and use that for your power supply. I did that once in my teen years when money was hard to get. I wanted a radio in my room to listen to at night, but could not afford a new one (tube-type radios in those days were fairly expensive and very large). I could buy cheap used 6-volt tube-type car radios at junk yards. So I bought a cheap 13 volt battery charger and a 12-to-6 volt vibrator (this was before transistors were widely available) to power a used car radio that I listened to for years.

They don't get much smaller. Here's a 60W and a 100W, either one for less than twenty bucks.
http://www.surpluscenter.com/item.asp?item=11-3353-24&catname=
http://www.surpluscenter.com/item.asp?item=11-3353-12&catname=

You already have a 12 VDC power supply - ie a car battery. So if money is a concern use the battery in your car.

You could as Lancie mentioned use a charger BUT watch the voltage at low current levels. You could supply load with battery and then float battery on the charger. This should keep voltage at 14 maybe 14.5 or less depending on current load.

Dan Bentler

kapooski2012 said:

Great source mendonsy thanks...but how many watts decision,decision!!

Click to expand...

Car horns can be very high or very low powered...

Headlights, now you're talking 15-ish amps, more for halogen.

the little indicator lights in your dash and even your turn signals are just a few sometimes fractional watts.

If you need more than 5 amps, do the battery + charger as suggested by Dan.

I have a 50w 12vdc power supply in a freezer control panel which uses 12vdc for led indicators in what could best be described as a pinball machine type picture of the machine, with the lights placed and labelled on it. There are about 30 of these LED indicators driven by this little power supply and there are also a half dozen 22mm industrial IEC type 12v incandescent indicator lights on the door. We replaced the oem SOLA linear supply with a din rail mounted PULS after it finally failed a few years ago.

PULS has become my choice for high quality, but we also have a boatload of the Meanwell power supplies (dirt cheap) and not a single failure in over 6 years.

They are in nice and dry panels powering our Ethernet switches and fiber converters and associated other interface devices. I prefer the PULS for things that may result in short term overloads and in nastier environments.

The first link is Meanwell power supplies - I have used quite a few in my time and many 24VDC/24VDC switch modes as well - never had a failure.
Can be a bit noisy - as can all switch mode power supplies - even the expensive ones.

Got a Meanwell 100 watt on the way should be here in a few, thanks to all the contributing members. Trainer coming along fine, now to figure out how to manege all these wires thinking about some wire duct all these sizes to pick from....

kapooski2012 said:

Got a Meanwell 100 watt on the way should be here in a few, thanks to all the contributing members. Trainer coming along fine, now to figure out how to manege all these wires thinking about some wire duct all these sizes to pick from....

Click to expand...

Yep, you can hide a lot of stuff in wire duct!

We used to use +/-12vdc supplies often back when we had to build our own control cards out of OP amps. It is still pretty common with all the board level analog stuff. Once everything went digital there are a lot of things that at one time were staples that now collect dust on the shelves.