Using two or more relays for large currents.

Thread Starter

stoichiometry

Joined Jan 14, 2011
4
Hello,

I am working on a windturbine for an off-grid application. I have a circuit diagram for a small charge controller that functions well with small 12 Volt relays. The problem (well, not really problem :D) is that I've created a turbine that produces some large current ... I am not interested (yet) in making a new stator for higher voltage/lower current.

So, my question ... is there a way to split the incoming 12 Volt DC current (160 amp max @ high wind speeds) over two or more automotive style relays?

Kindly,
Matt
 

GetDeviceInfo

Joined Jun 7, 2009
2,196
if you could limit your current to the value of an individual relay, switch the relay, increase one more step, switch the next relay, etc., that may work. Trying to pull multiple relays in to service the total current would likely end up in an explosion of contacts.

I'm sure you could find an old motor starter contact capable of your current, kicking around somewhere.
 

thatoneguy

Joined Feb 19, 2009
6,359
Loads will automatically "split" based on the amount of resistance they have (current they draw).

If you put 2 12V 10W light bulbs on the output, they would both draw the same current. Current isn't going to be forced through the bulbs unless the voltage increases.
 

SgtWookie

Joined Jul 17, 2007
22,230
You might just use a Ford automotive starter solenoid (relay). Not sure how well the coil will stand up under continuous use, but you could use a solenoid driver circuit to reduce the current flow through the coil once the relay engages.
 

soda

Joined Dec 7, 2008
177
Hi

What you need to switch those type of amperages is a contacter-relay wich is a heavy duty relay. Don't even think of using a normal low voltage relay because it will burn up instantly.

When we use electronics with our high voltages, we usually use stud triacs which then drive the contacter- relays.

The one i show you is only a small 230vac type and can switch currents up to 20A

I think, to be able to buy one you need to show a high voltage(50kv) license.
 

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thatoneguy

Joined Feb 19, 2009
6,359
why are you not regulating the alternators field? Switching load current can be done as a safety, but not as regulation.
I have the same question, especially when dumping the load simply to create heat.

If the dump load is active a lot, you may want to get a bigger inverter and run more stuff from wind power, or do a grid-tied system.
 
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