Sourcing high voltage isolation switch for 150V @ 40A

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stube40

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Any ideas who might be able to supply a high voltage isolation switch capable of handling a constant 150V @ 40A?? The Jaycar SF2245 ones I selected weren't up to the job and began to melt (I thought they might!!)

**broken link removed**

I've tried all the usual suspects RS, Farnell etc. I live in QLD, Australia, but worldwide shipping is no problem.
 

That switch from Jaycar is not only a low-voltage switch (12Vdc) but it designed to isolate batteries in vehicles in no-load situation ..
For example, 12V hydraulic HIAB, additional trailer etc. etc.

Am I assuming correctly that you are going to switch 150V DC?

Rgds,
IanP
 


Yeah, that's right - 150V constant (for about 1 minute at a time).

I pulled the Jaycar switch apart and noted that the copper busbar (the rotary part) had welded to the 2 copper bolts. Clearly this was an issue with arcing at high voltages and hence the gap is not big enough. In other words, I proved that they were correct to specify it at 12V
 

In this case have a look at the OT-40 ..
**broken link removed**


I think you can try to source it at ABB – Brisbane, or **broken link removed**

Rgds,
IanP
 

IanP said:
In this case have a look at the OT-40 ..
**broken link removed**


I think you can try to source it at ABB – Brisbane, or **broken link removed**

Rgds,
IanP
Click to expand...

Thanks Ian. I must admit to being a little wary though about using a switch rated to 40A with an actual 40A feed. Shouldn't I overspecify the switch?

I'd already found this neat Clipsal DC switch

http://updates.clipsal.com/ClipsalOnline/ProductInformation.aspx?CatNo=4CB140/6DC&ref=

But it was only rated to 40A too.
 

It actually may work, all depends on how often are you intend to use it ..
I’d like you to consider an R-C snubber in parallel with contacts ..
Typical (un-optimised) value is 100Ohm+0.1uF, more on this issue you can find here:
**broken link removed**

Rgds,
IanP
 

A snubber looks quite nice, but it doesn't help much to solve the problem of switching 150 V DC. Simply, the switch must
be able to disconnect 6 kW at 150 V, respectively more, if it's intended to work under overload condition as well. That means,
the switch must be designed to stand the arc and has special means to quench it. The situation is different from AC switches, where
the arc is time limited until the next zero crossing.

With low voltage DC circuits, a snubber can supress arcing effectively.
 


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