Where can i find such a relay?

[tecMec]

I'm working on a battery protection system. The DC current running out of the battery bank is 100A continuously, and 200A for few minutes. The DC voltage of the system can reach to 60 VDC.

I guess the solid-state relay will do the job (correct me if I’m wrong).
Also, the battery bank must be shut down with "normally Open" contacts of load relay.

now, where can i find such a relay?

 

[CarlPugh]

Would a mechanical relay work?
Solid state relays normally have a higher voltage drop than mechanical relays.
If mechanical relay would work, you might try Ross Engineering Corporation.

 

[ScottyUK]

ABB make a range of clapper-type contactors for load switching of DC, as do Telemecanique and Siemens. The ABB range is much cheaper in the UK, but still quite pricey as it is a minority-interest product. They seem popular with the crane manufacturers.

For fault protection, consider HRC fuses. DC breakers have a hard life. ABB and Siemens both make DC-rated MCCB's if you prefer that option.



-----------------------------------

Start each new day with a smile.

Get it over with.

 

[sreid]

Mechanical relays to switch DC power must be rated for the application. When the contacts open, a self sustaining metallic arc may form that must be extinguished. This is often done with magnetic blowouts. AC relays (typically) extinguish the arc at zero current crossing.

Solid state relays are usually made with SCR and are used in AC circuits only.

A high power solid state switch that would work is called an IGBT (Insukated Gate Bipolar Transistors). Powerex makes an extensive line of these. Some circuit design would be reuired to implement the Gate Drive to turn the device on and off.

 

[Digitalwoodshop]

Your answer might be using a Mercury Displacement Relay.
When I worked at the Sony CRT plant in San Diego the large CRT degaussers went through relays in about a year. A new line was installed with the same 3KV degausser with a upgaded trigger circuit that used Mercury Displacement Relays. In 4 years they never failed.

Check out this site to see the relay and data.

http://www.gordosales.com/mercury_relays.htm

 

[tecMec]

CarlPugh (Electrical) Mar 12, 2004
Would a mechanical relay work?

i really dont know if they do or dont,
i have found in a site, the solid state relays are the best of batteries protection.!

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Digitalwoodshop (Electrical)

i have checked the site you have posted,
i found the relays are for AC use not DC as i have requested.
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I have been advised to use two relays in parallel , to stand a load of 200A (DC current).

Any comments.!

 

[ScottyUK]

Comments are......

Check out the suppliers I originally listed as producing contactors designed for DC operation. AC contactors pressed into DC service have a short and violent life. Use the a contactor designed for the job.
ABB's p/n's start IORE..... for a n.o. contact, NORE..... for a n.c contact.

You mention protection: fault protection of DC switchgear is a pretty specialised field. The simple and cheap way is to use HRC fuses, otherwise get ready to spend a lot of money.



-----------------------------------

Start each new day with a smile.

Get it over with.

 

[busbar]

Depending upon reliability needs, something electromechanical like

http://www.tycoelectronics.com/prodnews.asp?ID=564

may work.

 

[aviat]

I don't know if you are looking for current protection or voltage, or both. If you require current protection you could use a current limiter. It would have to be changed it over current occurs. Or there are circuit breakers that operate to that range.

http://www.marine.com/cgi-bin/tame/cat/show-detail-item.tam?item.ctx=74640

 

[Bung]

You might need to be a little careful with fuses - the interrupting capability can depend on the load time-constant (inductance). Your average everday FCL fuse is designed for primarily ac operation - if it is rated for dc, make sure it is capable of dealing with whatever your load is.


Bung
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