Connecting SPDT Relay

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Old 09-21-08, 11:35 AM
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Connecting SPDT Relay

I need to provide backup power from a battery via an inverter for a pump. I was told I needed a Single Pole Double Throw Relay. I've got a RIBU2C relay for the job. But I haven't figured out the wiring yet.

So I need to connect the relay to my main power supply and from my inverter.

Can anyone tell me what wires need connecting?

This is what the inverter has for wires:

Relay 1

Coil input
Common = white/yellow
10/30 v. = white/blue
120 v. = white/black

Contact output
Common = Yellow
N/O = Orange
N/C = Blue

Relay 2

Coil Input
Common
10/30 v. = White/Grey
120 v. = White/red

Contact Output
Common = Purple
N/O = Brown
N/C = Grey

When I connect power to the white/black and white/yellow the light for Relay 1 comes one and when I connect power to white/red and white/purple the light for Relay 2 comes on.
 
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Old 09-21-08, 01:44 PM
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What kind of pump are you trying to run using an inverter? How many amps does the pump draw? What size inverter do you have? There may be a simpler way to do what you are trying to do.

Travis
 
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Old 09-21-08, 02:25 PM
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The pump is a Taco 0010 and the inverter handles 400 watts. So it is a small circulation pump that draws 1.1 amps.

We have a battery store here that specializes in these types of setups and he said I needed a single pole double throw relay. He drew me a diagram for wiring it but I'm having trouble following it. If I don't get instructions here on how to wire it I'll go back tomorrow and get clarifications.
 
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Old 09-21-08, 08:40 PM
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Why is it you need the relay? This sounds like a fish tank or coy pond pump. Why is it you can't plug the pump right into the inverter. I ran the same type set up for my fish, after the hurricane we just had. I did this for about a week. I am just trying to understand your situation.

Travis
 
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Old 09-21-08, 09:45 PM
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The pump needs to run from the main power supply. We experience frequent power outages -- usually for just a minute or less, but one time for four hours. Fortunately it was not colder than 0 Fahrenheit than time it was out for four hours, but where we are it can get down to -50 F. So when the power goes out, the power from the inverter takes over making sure the pump continues uninterrupted. This is for a Greenwood Wood Burning Boiler. If there is no backup power, the glycol in the boiler can start boiling in less than 15 seconds. Also the backup power can continue circulating hot glycol to the house to provide heat there if the power happens to be off for an hour or two.
 
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Old 09-21-08, 10:05 PM
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It should look something like this. When the power is lost. It should switch from a/c power to the inverter power.

Travis
 
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Old 09-21-08, 10:13 PM
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Travis .,, You have right idea with that set up and now it got me thinking maybe there is a more simple set up a UPS unit will work as well.

However I belive the OP did allready brought the inverter if that the case some Inverter do work as charger function to keep the battery{s} charged while still using normal power but once the power go out the inverter will automatically switchover.

But any chance can the OP run me the inverter model number ?

Merci,Marc
 
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Old 09-22-08, 06:35 AM
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Any trickle charger will keep the battery charged. It doesn't need to be a part of the relay circuit.

Pros ... correct me if I'm wrong, but I believe you have to also switch the neutral to avoid blowing the fuse or breaker in the inverter. Most inverters use a "hot neutral" and if connected to AC neutral it will cause a direct short to ground when the relay switches to the inverter.

Rather than hardwire anything, I would build the entire rig into a metal enclosure with a receptacle for the pump and two edison plugs on pigtails -- one to plug in to the AC and the other to plug into the inverter. If the relay ever fails you can just manually connect the pump to the inverter.

Here's the connection scheme from the Spec Sheet (my additions in red & green):



As long as the relay has AC power the pump will operate on the "normally open" connections (which are closed when the coil is powered). When the AC power goes off, the coils will de-energize and the "normally closed" contact will feed power from the inverter.
 
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Old 09-22-08, 10:40 AM
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Thanks for the diagram. Yes, my intention has been to use a recepticle. I've got a large box with an extender to provide plenty of space. I'll see if I can get it wired this evening after work.
 
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Old 09-22-08, 10:46 AM
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Originally Posted by french277V View Post
Travis .,, You have right idea with that set up and now it got me thinking maybe there is a more simple set up a UPS unit will work as well.

However I belive the OP did allready brought the inverter if that the case some Inverter do work as charger function to keep the battery{s} charged while still using normal power but once the power go out the inverter will automatically switchover.

But any chance can the OP run me the inverter model number ?

Merci,Marc
Yes, I already have the inverter but I don't remember the make or model. I can check on that tonight and let you know. I also have a nice trickle charger the battery store recommended for the job.
 
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Old 09-23-08, 07:02 AM
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Inverter is Samlex SI-400HP

Originally Posted by french277V View Post
Travis .,, You have right idea with that set up and now it got me thinking maybe there is a more simple set up a UPS unit will work as well.

However I belive the OP did allready brought the inverter if that the case some Inverter do work as charger function to keep the battery{s} charged while still using normal power but once the power go out the inverter will automatically switchover.

But any chance can the OP run me the inverter model number ?

Merci,Marc
It is a Samlex SI-400HP. I got it wired yesterday and appears to be working normally.
 
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Old 09-23-08, 07:09 AM
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Originally Posted by Rick Johnston View Post
Any trickle charger will keep the battery charged. It doesn't need to be a part of the relay circuit.

Pros ... correct me if I'm wrong, but I believe you have to also switch the neutral to avoid blowing the fuse or breaker in the inverter. Most inverters use a "hot neutral" and if connected to AC neutral it will cause a direct short to ground when the relay switches to the inverter.
Thanks very much for the extremely helpful diagram. I wired it up yesterday afternoon and it works. It does seem this inverter uses a hot neutral. When the power is from the inverter and I plug my recepticle tester in, the three light pattern says "Hot/Neutral reverse." But when power is from AC the light pattern says it is correct.

When the power if from AC both relay lights are on. When the power is from the inverter no relay lights are on. Is that how it is supposed to be?
 

Last edited by Rick Johnston; 09-24-08 at 04:24 AM. Reason: Correct quote formatting (add endquote)
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Old 09-24-08, 04:24 AM
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The relay lights are telling you that the coils have power. When the device is working from the inverter the coils are not powered. This is normal.
 
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