DPST vs. DPDT relay wiring differences

bcraun · Joined: 28 Nov 2011 Posts: 28

I _thought_ I ordered DPDT relays, but I received DPST models (JQX-62F). I see in the parts list that DPST are acceptable, but the wiring diagram for power, as an example, is obviously going to be different if DPST relays are used. I've puzzled through the electron flow and am not sure I see how the DPST relays are wired. From the graphic in the step for wiring power, there are yellow ring terminals that appear to be used in subsequent steps. Has anyone else used DPST relays for the panel? If so, what are the changes necessary to the power wiring diagram.

Thanks.

bcraun · Joined: 28 Nov 2011 Posts: 28

I figured it out.

Sketchin · Joined: 08 Jan 2013 Posts: 169 Location: Calgary

I would love to know how you figured it out

bcraun · Joined: 28 Nov 2011 Posts: 28

The simple answer is that you _must_ use DPDT relays. The ones I received were DPST and cannot be used in this application. Both sets of throws are used and there's no (safe) way to use DPST relays. It seems that the Chinese product numbers are the same in some eBay listings. Be sure to look closely at the pictures of the relay and ask the seller to confirm the number of poles/throws before purchase. That's about all I can offer. It was simply a mistake on my part.

Beerginner · Joined: 11 May 2012 Posts: 7 Location: Wellington, NZ

Yeah to be on the safe side you want the JQX-62F-2Z (2Z seems to indicate DPDT) some also use 2C instead of 2Z

**kal** · Posted: Wed Jan 23, 2013 5:01 am Post subject:

Sorry, that is incorrect.

As my instructions state, you do not need DPDT (double pole double throw) relays as the second "throw" that the "pole" connects to is not connected in any my wiring diagrams. Therefore using DPST (double pole single throw) will indeed also work.

I'm not sure what you mean by "Both sets of throws are used and there's no (safe) way to use DPST relays.". Do you mean the throws are shorted together in the relays you purchased? That would then not be a DPST relay.

You may have been sent the wrong thing or may be confusing the terminology or wiring incorrectly (?)

In the image below, the second "throw" for each of the 3 relays are the 2 screws at the top. There are 3 diagrams and none of them have the top 2 screws used, therefore double throw is not required:

Kal

Sketchin · Joined: 08 Jan 2013 Posts: 169 Location: Calgary

On the relays I got, the top right connection is not there. In the schematic its the #2 connection with the red wire running to the other 2 relays. Is that not the second pole?

I have also compounded the problem by ordering 220V coils! Stupid chinese ebay adds...

**kal** · Posted: Wed Jan 23, 2013 4:21 pm Post subject:

Sketchin · Joined: 08 Jan 2013 Posts: 169 Location: Calgary

So it looks like I must've got a spst then, as there is no screw in the top right NO side.

Thanks alot for the help, and sorry to be a pain, I just dont want to re-order and get the wrong thing again!

**kal** · Posted: Wed Jan 23, 2013 5:11 pm Post subject:

That is definitely not single pole. I can see th two vertical copper poles. See my previous text explaining which are poles and which are the throws.

Your relay in the picture is upside down compared to mine. The place your arrow points to is the INPUT to the relay. This doesn't matter in a SINGLE THROW relay however.

What do you mean "this connection is not there"?

Kal

Sketchin · Joined: 08 Jan 2013 Posts: 169 Location: Calgary

There is no screw. On mine, I can see where the 240V input is, and where the coil is (2 holes on either side), then there is only 1 screw terminal on the output. The copper piece goes to both sides, but the metal connecting the screw terminal to the metal internally is not there on the one side. Meaning there is nothing to connect to on the relay for the #2 NO connection that goes to each relay.

When I get home I can take a picture.

mrarkhan · Joined: 15 Jul 2017 Posts: 1

Hi Dear Mate,

I got the DKI JQX-62F-2Z relay for ACV TO DCV AND DCV TO ACV, In simple words, I have solar panels so i need the auto transmission shifting device if ACV goes OFF so I get the DCV automatically turn ON, And when DCV goes off the ACV trun ON. so kindly advised me how to I put wires in it, I mean the wiring diagram.
Thanks in Advance
And sorry for my poor English.

**kal**

Welcome to the forum!

Tungsten · Joined: 06 Dec 2014 Posts: 318 Location: Buffalo, NY

Sketchin can you post a picture of what you're talking about?

GAParkins · Joined: 07 Jan 2016 Posts: 29 Location: South Florida

None of the diagrams, schematics, cocktail napkin sketches, etc. for a 30A or 50A brewing control panel ever need DPDT relays. The only diagrams I've seen need 2 poles, but none that I've seen ever use the NC contacts from a DPDT relay. The relay is being used as a switch that can offload the high current required by the heater elements from the pilot-duty (<10A) equipment mounted on the door of the enclosures. The 50A DPST contactors I've sourced use about 0.06A at 120VAC to operate the coils. That means the door-mounted equipment isn't stressed, and the cable hinge between the door and the body of the enclosure only requires #16 AWG wires, and is a lot smaller and more flexible.

The thing to watch out for is that you don't EVER forget that pilot duty switches and wiring are still connected to load-rated sources. Please make sure that you use proper overcurrent protection to protect the wiring for the pilot circuitry! In other words, if you step down from a 50A-rated #6 AWG supply cable to feed a 10A-rated 22mm door switch with #16 AWG switchboard wire, make sure you fuse it at (or very close to) the step-down point.

All it would take is one resistive connection, and then all the smoke would leak out of your control panel wiring.

A control panel with 500 decisions regarding design, equipment, techniques, materials, etc. that has 99% accuracy still has five screwups. Be careful, and be thorough.