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Old August 8th, 2018, 10:14 AM   #1
Elcan
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480 VAC to 24 VDC.

Hi all,
What is your opinion about using a 480 VAC (3 phase) to 24 VDC power supply compared to using a 480 VAC to 110 VAC transformer and then a 110 VAC to 24 VDC power supply?
Is using the 480 VAC to 110 VAC transformer option better regarding filtering noise, for example?

Thank you!
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Old August 8th, 2018, 10:23 AM   #2
rdrast
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I use them all the time. Much simpler, and all of the 480x3 to 24VDC supplies I use are isolated through the DC-DC converter of the switching supply. Much simpler. I've never noticed any switching noise on the 24V side either.
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Old August 8th, 2018, 11:03 AM   #3
jaden
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Depends on your needs, but I find 120 VAC handy to have in a panel, such as Plug in for a laptop, etc.
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Old August 8th, 2018, 11:35 AM   #4
Timeismoney08
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.

I've had so many issues with them. I always step it down twice to get to 24V. I assume it's due to the large step down.

When I worked for a tier 1 supplier, it was a company policy, that we could not use 480V to 24VDC PS.


Hope that helps.
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Old August 8th, 2018, 11:35 AM   #5
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Depends on the needed power rating but if you talk about one with three-phase input it will probably have a large power and in this case the advantages are big compared to use a transformer:

- Saves space in the cabinet
- You avoid an important heat source as the transformer is.
- You avoid unbalanced intensity between phases.
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Old August 8th, 2018, 11:37 AM   #6
scott.lawrence
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I like the power supplies over the transformer... just makes the job faster/cleaner
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Old August 8th, 2018, 11:41 AM   #7
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We use 480-24vdc power supplies in just about everything, and they work well.
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Old August 8th, 2018, 11:51 AM   #8
Elcan
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Quote:
Originally Posted by Timeismoney08 View Post
When I worked for a tier 1 supplier, it was a company policy, that we could not use 480V to 24VDC PS.
Do you know why?
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Old August 8th, 2018, 12:17 PM   #9
Timeismoney08
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Quote:
Originally Posted by Elcan View Post
Do you know why?
Because they found them to be flaky. If the 480V varried, it changed the 24V end greatly. Secondly, they would just fail.
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Old August 8th, 2018, 12:30 PM   #10
Ken Roach
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We use PULS 480V 3-phase to 24V bulk power supplies for all of our heavy 24V needs. In our experience they are efficient, compact, and reliable.

Previously we used Phoenix Contact QUINT series, and they were reliable as well. We switched vendors just for distribution and price advantages.

In the places where 480V is flaky (like Japan) we run the critical stuff on 24V battery buffering units.
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Old August 8th, 2018, 12:42 PM   #11
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Quote:
Originally Posted by Ken Roach View Post
We use PULS 480V 3-phase to 24V bulk power supplies for all of our heavy 24V needs. In our experience they are efficient, compact, and reliable.
+1 for PULS. The QT20.241 is our standard power supply. Available worldwide, including China (which is unfortunately where we build a lot of our stuff now).
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Old August 8th, 2018, 12:53 PM   #12
Elcan
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Quote:
Originally Posted by Ken Roach View Post
We use PULS 480V 3-phase to 24V bulk power supplies for all of our heavy 24V needs. In our experience they are efficient, compact, and reliable.
What about noise? A motion components distributor is saying the 480 VAC to 24 VDC power supply in our control panel can be introducing noise the motion sub-system.
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Old August 8th, 2018, 01:10 PM   #13
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Quote:
Originally Posted by Elcan View Post
What about noise? A motion components distributor is saying the 480 VAC to 24 VDC power supply in our control panel can be introducing noise the motion sub-system.
Every motion guy I've heard complaining about noise was trying to sell some kind of smoothing component. Sometimes they were actually necessary.
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Old August 8th, 2018, 01:36 PM   #14
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Quote:
Originally Posted by Ken Roach View Post
We use PULS 480V 3-phase to 24V bulk power supplies for all of our heavy 24V needs. In our experience they are efficient, compact, and reliable.

Previously we used Phoenix Contact QUINT series, and they were reliable as well. We switched vendors just for distribution and price advantages.

In the places where 480V is flaky (like Japan) we run the critical stuff on 24V battery buffering units.
Phoenix will do competitive costing. Send them the info on the PULS and price.
Usually they will beat it by a few bucks.
I keep them inline by sending them pricing from Automation direct.
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Old August 8th, 2018, 06:25 PM   #15
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I've used the A/D and Puls brands with zero problems. There are places where it makes more sense to skip the transformer altogether. I can't imagine a noise problem being made worse, and expect the overall efficiency to be better with a 3 phase input.
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