Automatic DC transfer Switch

[Humble2000]

Dear Friends,
Does anybody know of a manufacturer of Automatic Dc Transfer switch capable of switching 150A at 125VDC?
I have called places I know like eaton they don't have it..

Thanks

 

[davidbeach]

Diodes? Bring both sources to a pair of diodes and the source with the higher voltage will supply the load.

 

[Humble2000]

No this is an automatic transfer switch.

Two source of supply and one load.In case of losing one source the switch with atumaticcally transfer the load to the other source...

 

[davidbeach]

Diodes will do that.

 

[ScottyUK]

Diodes is definitely a good option. No interruption to supply. This is done routinely with hi-rel systems using multiple redundant supplies to supply critical loads. Only downside is that diodes don't like high fault currents because of the low I²t withstand rating of the semiconductor junction, so if you have a large fault level you can either over-size the diodes - entirely possible at only 150A - or look at electromechanical means.

The alternative might be a bar and shaft type contactor with a combination of NO and NC poles providing the changeover, or a pair of contactors switched in antiphase. ABB's R-Line is one such type, with similar products being available from Telemechanique, Siemens, Hubbell, etc. DC contactors are minority interest products and are therefore expensive compared to an AC contactor of equivalent rating. They're available up to at least 1500V and 6000A, although the choice of suppliers is more limited at these high ratings.

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I don't suffer from insanity. I enjoy it...

 

[Humble2000]

Thanks for all replies.
I am mainly looking for an assembelled package rather than making one with diods.

 

[ScottyUK]

You're likely to be looking at a custom or semi-custom design. Any halfway competent panel shop should be able to make the panel. The circuit is pretty simple too - I've already identifed the difficult components for you. The control circuit should be well within the scope of a competent engineer.

Don't forget that most MCCBs primarily designed for AC service have a limited DC rating, and a standard AC transfer switch power circuit (MCCB, busbars, terminals, enclosure) might be suitable for DC service, depending largely on the nature of your load. The major limitations on MCCBs in DC service are: they're usually confined to loads with little or no inductance; their DC voltage rating is much lower than for AC duty - you may need multiple poles in series; and only true thermal-mag or pure mag MCCBs will work correctly. Self-powered electronic tripping modules don't work on DC.

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I don't suffer from insanity. I enjoy it...

 

[itsmoked]

Okay just keep in mind that two of these(randomly selected)diodes would provide instant switching automatically and be the size of a shoe box. $150 x 2 plus a heat-sink $150?


Rated @ 475A all day long. Peak reverse voltage: 3,000V
Peak current 7,800A.

Trying to match this with a relay.. No comparison.

http://www.irf.com/product-info/datasheets/data/sd500n.pdf

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[DanDel]

You could try ASCO:

ASCO Power Technologies
50 Hanover Road
Florham Park, NJ 07932
Phone: 1-800-800-ASCO (2726)
Fax: 1-973-966-5709

http://www.asco.com

or Russelectric:

781-749-6000
Mike Faulkner
Purchasing Manager
mfaulkne@russelectric.com

even though they don't specifically list DC in their literature.

 

[Humble2000]

Thanks everyone.
ASCO got it.