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intrinsically safe safety 12v

Hi Folks: I'm hunting for a solution to this problem. I have a 13.2V battery (charging) in a safe area. This goes through a custom barrier (ISCOM) to a computer in a hazardous area. There is a new intrinsically safe solenoid in the hazardous area, but it needs about 10V at 30mA to switch. The added current would blow the ISCOM, which already doesn't have the voltage the solenoid needs. The common zener-resistor barriers I've seen drop too much voltage and we have no 24V that the active devices require. The best we've come up with so far is 9.6V that works when the solenoid is warm, but not cold (like today). This is taking into account the voltage drop in all the wiring as well. Any ideas apprecieated! Thanks! Harry

Reply to
HarryHydro
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When you say "hazardous area", I assume you mean one that may have an explosive atmosphere, is that right? And in an industrial setting?

Could you tell us a bit more about the exact requirement?

Cheers,

Phil Hobbs

Reply to
Phil Hobbs

Can't you use a pneumatic actuator? Or a mechanical link?

Reply to
Homer J Simpson

An I.S. DC-DC barrier would be preferable to the somewhat dated Zener blocks. The input supply voltage feeds 1:1 to the load but is galvanically isolated and I.S. approved

Pepperl+Fuchs do a whole range of I.S. isolators. Google instantly turned up ...

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look at the kFD2 solenoid driver range. Expensive naturally. john

Reply to
john

So hang a small dc-dc converter across the battery to get enough voltage to drive through a conventional barrier?

Reply to
nospam

Hi: Thanks for the reply. In the safe area we have a 12V battery bank and charger. There is a custom barrier box for a computer that reside in the hazardous area. There are pneumatic operators here also . In an effort to save time and money (hard conduit, etc.), we're using an intrinsically safe solenoid set. These solenoids need 10V @ 30mA to switch. The computer provides an open-drain FET for switching. This may be 12V only, being clamped to the + rail. What we've done is use another custom barrier for the solenoid, but I think these are expensive to. Overall, it's still cheaper than re-tubing.

Reply to
HarryHydro

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