24-vdc to 24-vdc Isolated Power Convertor

[pmover]

Bear with me as i am a gearhead, not a sparky . . .

I've a need for a 24vdc - 24vdc Power convertor (from ungrounded 24-vdc power supply [floating reference ground] to a 24-vdc grounded power supply). the 24-vdc load is powering an AB PLC and I/O Card - CompactLogix).

The load data are as follows:
Cat. No.: -1769-PB2
Description: -Compact 24V DC Expansion Power Supply
Operating Voltage Range: -19.2…31.2V DC
Power Consumption, Max.: -50 VA @ 24V dc
Current Capacity: -2.0 A @ 5V-0.8 A @ 24VT
24V DC User Power Capacity (0...55°C): -
Inrush Current, Max.: -30 A @ 31.2V DC
Line Loss Ride Through: -10 ms…10 s
Overvoltage Protection: -For both +5V DC and for +24V DC

The Load data is at:

http://www.ab.com/en/epub/catalogs/12762/2181376/2416247/407648/6380592/tab2.html

i have located a convertor supplier (Vicor), but the convertor supply (a 400W DC-DC Maxi Convertor) device:
1)connections do not have screw terminals,
2) DIN rail mounting is preferred,
3) and the device will go to current-limiting at PLC power-up (in-rush current). i'm thinking the in-rush current is not that critical, analogous to placing a significant load (flow) on pressure regulator at start-up, until the downstream pressure slowly increases. So, after the PLC is powered-up, the current-limiting will no longer be active, then the output voltage will be restored.

i will be following up with the supplier next week, but meanwhile, if anyone can provide alternatives and/or address the 3 issues, i appreciate your feedback.

Thanks!
-pmover

 

[Henneshoe]

Here are 2 options from Digikey that are DIN mounted and have screw terminals. I think either of them should be able to handle the inrush, but maybe someone here with more experience than me should weigh in on that issue. I am sure there are other options.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=277-1922-ND

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=281-2017-ND

 

[pmover]

Thanks Henneshoe . . . your response made me think of a matter previously neglected and i investigated the Weidmuller products.

due to the difficulty i am having in locating a device, the cost involved, and the additional 24-vdc load on power supply, the better option is likely with an AC-DC converter.

i forgot about the load on the 24-vdc system, which has 3 24-vdc circuit breakers (10A, 15A, and 30A). Powering up this PLC may overload the existing circuit breaker used to provide power (especially if there is already a load); thus tripping. Then again, powering the PLC is not a frequent event, but a prudent engineer should not design an electrical system without considering all loads and operational possibilities.

I will most likely have the AC-DC converter plugged into an UPS device to avoid any power interruptions.

Thanks again!
-pmover

 

[ScottyUK]

Schaefer's DC/DC range is very good, especially the C Series.

http://www.schaeferpower.com/products_dcdc_converters.html

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