What type relays for a water fountain display off a 1762-OA8 ?

[Rob S.]

Good Morning ,

I have a customer that has a large pool and they have timed fountains. The valves are 12 vac , and they are being fired from a Allen Bradley 1762-OA8 Solid State Output module. They are using very slim relays to trigger the fountain valves. They are going they a lot of relays and bases . What type of relays would you recommend, that has a long cycle life ? For some reason , they had several 24 vdc coil relays in some bases.

Thanks in advance.

 

[Steve Bailey]

What are the inrush and holding currents of the valves? You need to match the ratings of the relays to that. Also, how often do the valves have to turn on and off? If they cycle at a high rate, consider using solid-state relays.

 

[Rob S.]

Inrush is about 2.5 amps
Holding is about 1.5 amps

Thanks . Yea, I think Solid State also.

 

[Rob S.]

I was looking for solid state relays , but I am having a problem finding a solid state relay with a load voltage of 12 vac or lower. Would any of you have any thoughts ?

Thanks so much .

 

[Jeev]

Crydom make some SSR's that will go down to 12VAC on the load side, but they are not rated any lower than that. Have a look at their DRA1 and DRA4 series relays. Weidmuller also make some in the TERMSERIES, but again these are not rated below 12V AC on the load side.

It also sounds like you're losing some relays and bases, because they are the wrong part. What voltage is the 1762-OA8 supplying to the coils of the relays?

 

[shooter]

You can put diode bridges to all outputs, that way you can use DC outputs.

So no need for interposing relays, and you will have more speed and time control.

 

[Rob S.]

The 1762-OA8 is being supplied with 120 vac. The fountain system is 12 vac. I took notice that some of the relays they had in the panel , the coils were 60 vdc.