[RE-wrenches] DC Solenoid Coil Current

[Exeltech]

Larry,

A latching relay isn't suitable for fail-safe applications.
 
Look into the "Kilovac Czonka III EV200HAANA".  This series has a coil "economizer" that reduces coil current (and thus power consumption) after pull-in.  Rated coil power is less than 2 watts.  Models are good to 900Vdc and up to 500A.
 
Coil inrush current on one model I found is spec'd at 3.8 A for a 130 milliseconds, so you'd need an external transistor to drive it from the computer.  If power consumption is a critical aspect, use a suitable MOSFET.  If you don't mind wasting another watt or two, a bipolar NPN will also work.  The coil current throttles back to less than 100 mA at 12Vdc after contact closure.  Because a specialized electronic power supply is driving the coil, Kilovac rates the DC input to the coil driver at anything from 9Vdc to 36Vdc.
 
Here's the Allied page: http://www.alliedelec.com/search/productdetail.aspx?SKU=70062411
 
Not cheap .. but excellent quality.  If you're a registered reseller with Allied, the $ is less.
 
 
Dan

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On Tue, 2/11/14, Larry Crutcher, Starlight Solar Power Systems <larry at starlightsolar.com> wrote:

Subject: [RE-wrenches] DC Solenoid Coil Current
To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Date: Tuesday, February 11, 2014, 6:43 PM
 
Hello Wrenches,
 
We're preparing to offer Lithium batteries to some of our customers as a replacement to lead acid in recreational vehicles. RV batteries can have multiple charge sources simultaneously so I have worked out protective circuitry to interface with a EMS computer. To insure failsafe operation, I need to install 2 solenoids that will be active 24/7, opening only when fault conditions are met.
 
The solenoids I have looked at (200 amp) have a coil current of about 1 ampere each which equates to 600Wh daily consumption. I'de like to reduce that BUT the computer only provides a +12v or 0 volt state. 

  *  Does anyone know of a latching solenoid that will work with a 12v hi/lo voltage state,
  *  OR an interface or circuit for hi/lo to control latching relay
  *  OR a solenoid with a very low quiescent current when on? 

Many thanks in advance, 

Larry Crutcher