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Forum Index : Windmills : Voltage Sensing Relays

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old mate's mate

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Joined: 11/08/2010
Location: Australia
Posts: 15

Posted: 05:48am 02 Jun 2011

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Team, salutations, the windy season approaches, time to dust off the dust, etc ....

Has anyone had any experience with using a Voltage sensing relay as a dump load controller ? Something like this

cheers

OMM

powerednut

Senior Member

Joined: 09/12/2009
Location: Australia
Posts: 221

Posted: 06:35am 02 Jun 2011

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$170 seems expensive for a dump load controller...

VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539

Posted: 06:48am 02 Jun 2011

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Hi old mate

Try Glenn's dump load circuit on the projects page, it is a beauty and costs less than $20 to build

All the best

Bob

Foolin Around

old mate's mate

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Joined: 11/08/2010
Location: Australia
Posts: 15

Posted: 11:23pm 02 Jun 2011

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Yo powerednut and Bob, thanks for the prompt reply and for sharing your opinions regarding the cost of the relay. The voltage sensing relays were given to me (Over AND Under (Window) sensing, like the one in the link, and a couple that sense Over OR Under (dip switch selectable). Both relays can be configured to be Latching or Non Latching.

In this particular situation the cost is not a variable within the function so if I may ask again:

Has anyone out there had any experience with using a voltage sensing relay as a dump load controller ?

cheers

OMM

toxsickcity
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Joined: 28/05/2011
Location: Australia
Posts: 8

Posted: 10:55pm 03 Jun 2011

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http://jaycar.com.au/productView.asp?ID=KC5377&keywords=volt age+switch&form=KEYWORD

I've used this cirucit on 24v dc to power it by using an 7812 reg & heatsink,

I put a resistor large value, 1m ohm to scale the input down, allowing me more voltage range.

costs 30$ and works well..

I also use this circuit for solar battery (low voltage disconnect), adding a Capacitor/diode on the Input can give this circuit a 10-20seconds allowance in drop of voltage
IE: Momentary Large Loads.

cheers

Janne
Senior Member

Joined: 20/06/2008
Location: Finland
Posts: 121

Posted: 10:44am 05 Jun 2011

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I haven't used them in dump load duty, but have succesfully utilized them as overvoltage protection for windmills.

They should work also as a dump load controller, they have all the specifications needed. Adjustable latching voltage, adjustable hysteresis.
The snag in them is the mechanical output contact. It the right conditions it will be swithcing quite often, so contact life could became a potential problem in this use. Best would be to use an SSR to switch the actual load, and just use the voltage relay for sensing and switching the main relay. With small currents the endurance would be limited only by the mechanical life.

On the other hand, as they're designed for industrial use, they're far more robust than a bodged electronics card.

If at first you don't succeed, try again.

My projects

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