Need a AC to DC converter

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LHarrington

Senior Member
Location
Saginaw Bay area Michigan
Good morning,
We need to purchase an AC to DC converter and need a recommended source for the following application. 200 HP compressor mild to moderate vibration. Clean environment, Secondary on main control Trans has been trended at 120 VAC +/- 5% we need to hold steady at 24 VDC. Load is under 200W, Ambient temp is 40 degree F to 100 degree F. Your thoughts and experiences are appreciated. Machine supplier has one but it is $770.00. Catalog's and web proves I can get it much cheaper. Unless I am over looking or not considering something. I replaced plenty but never sized one for myself so please be kind and learn me.

LHarrington
 
A little more info please.

You have a 120V/1/60 source that's varying +-5%.

You need to convert that 120V source to a stable 24VDC supply with 200 watts capacity.

What are you using the DC supply for?
How much variation on the DC voltage can you tolerate?

Where does the 200HP compressor and vibration enter the picture?
Will the DC converter be mounted on the compressor?

steve
 
Currently the compressor has a main control transformer taking 480 to 120, then the 120 is sent to a smaller transformer 120 to 24VAC, the 24 VAC is sent into the I/O module which converts the 24VAC to 24VDC. I want to eliminate the small transformer with a 120VAC to 24VDC converter and use the option the I/O module has to accept 24VAC or on the other side of the card it will take 24VDC. The manufacture left this option open to themselves because of various option these machines can have.
I had originally mistyped the wattage it should be load is under 20 Watts not 200.
I had list the compressor and vibration so everyone would under stand what I was putting it into. I wasn't sure if it would matter but wanted it to be known.

LHarrington
 
LHarrington said:
~I want to eliminate the small transformer with a 120VAC to 24VDC converter and use the option the I/O module has to accept 24VAC or on the other side of the card it will take 24VDC. ~LHarrington
Click to expand...

Not a whole lot you can do there..... A 120-24vac transformer and full wave rectifier circuit and voltage regulation will be doing the same thing... Sure you could build a voltage regulator super cheap with a few bucks at radio shack - especially at 20w, but the manufacturers card may be at a tolorance more suitable to the manchine, and let's not forget warrantee conflicts..... Will they warrantee the rest of the equipment if whatever other voltage regulator you use fails or is otherwise incompatable for other unknown reasons.????
 
Sounds like you need a 120vac/24vdc Power Supply rather than a Converter. I use the Phoenix Contact QUINT series on Allen-Bradley PLC's and have never had a problem. They also have a QUINT Ex series if your app is C1-D2 (doubtful).

http://www.phoenixcontact.com/global/signal-level-matching/242_25201.htm

If for some reason the 24vdc output is not tight enough (which would be hard to fathom) you could add a Vicor DC/DC Converter and do +/- 0.1 volts. If you do switching downstream of the Vicor you may have to add some Capacitance. Vicor is at vicorpower.com

Personally I think the $770 from the OEM is not a bad deal. At least their Tech Support would still like you :grin:

I was glad to hear that your comm problem appears to be fixed... for the moment at least. If your voltage-tolerance is beginning to tighten up I think you have an impending failure.
 
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