Solenoid valve conversion

Skiroy · Sep 6, 2012

I dont know if this is a proper question for this forum and I do not want to abuse this forum because it is very helpfull to me. But I have a A/C Numatics solenoid valve and manifold like this.

http://www.ebay.com/itm/NEW-NUMATIC...472?pt=LH_DefaultDomain_0&hash=item2a1d5b8ca0

My current PLC is set up for DC and I rather not have to add a 230V to 110V transformer just for this valve. Does anyone know if the you can just change the solenoid portion and convert it to DC instead of A/C? And would the manifold pins be consistent?

Thankx,

leitmotif · Sep 6, 2012

Call factory and see if they have a coil that meets your voltage desired. Many makers of solenoid driven equipment will have coils to meet almost any voltage need.

Make sure the voltage and current for the coil you want will match those of the PLC and do not forget to use MOV on PLC output to protect from coil collapsing magnetic field.

I am not sure what you mean by manifold pins.

Dan Bentler

elect_mf · Sep 7, 2012

I not to sure about that solenoid valve but all the solenoid valves I had used, I could always change out the coil to a different voltage.

keithkyll · Sep 7, 2012

Not in this case. "The Mark 55 Series direct solenoid actuated valve is AC voltage only. DC solenoids are not available for this series."
Link to catalog.

You can go down to 24AC. Manifold pins, etc. will be the same.

Skiroy · Sep 7, 2012

leitmotif said:
Make sure the voltage and current for the coil you want will match those of the PLC and do not forget to use MOV on PLC output to protect from coil collapsing magnetic field.

Dan Bentler

I only need to use a MOV(Shunt) for AC solenoids though right?

The PLC is a SLC 500 with relay outputs.It is using DC for the outputs but there is a section of the Output terminals not being used. The Com terminals say AC/DC so I assume I can use this open section with A/C even though the others terminal sectionc are wired as DC,right?

Mickey · Sep 7, 2012

Use a slave/interposing relay. Keep the PLC's relays all 24vdc.

For surge protection see PDF

milldrone · Sep 7, 2012

Skiroy,

I just want to give you a heads up about this particular brand/series. Because these units are direct drive, if the spool cannot shift the coil will burn out in about 45 seconds. If there is any liquid moisture in your air the spool will stick and burn the coil out. The outfit I work for has about 600 of these in a AC form factor, and we replace about 3 coils a week. If we have any moisture in our air we can loose 75 coils in about an hour. I should mention we use an insane amount of air. I don't know the SCFM but the motors total 4,200 hp. Here's a photo of one in the scrap bin that just happened today.

OkiePC · Sep 7, 2012

We use some direct acting DC valves by Numatics for vacuum with fair results. They are prone to clogging, but are pretty high flow and we don't suffer too many coil failures although the indicator lights seem to quit on us a lot. Ous suffer from cardboard dust since they supply vacuum to palletizing robot grippers.

I like Macvalves for pneumatics:
http://macvalves.com/MAC-Valves-Products/pneumatic-valves/

milldrone · Sep 7, 2012

OkiePC said:
We use some direct acting DC valves by Numatics for vacuum with fair results. They are prone to clogging, but are pretty high flow and we don't suffer too many coil failures

That would be what I would expect from a DC coil.

shooter · Sep 10, 2012

If the plc is relay it should say how much volt is max on the contacts, then you can use a contact. Please use a snubber circuit to avoid burning of the contacts.
for milldrone use a snubber over the contacts, this will heat the coil a little and avoid moisture.
This also avoids a high inrushcurrent and flashing.

Skiroy · Sep 10, 2012

Thankx guys. But to use this AC solenoid valve,Which is prone to going bad,I would need a transformer to supply the 110v,a snubber and a contactor or ice cube relay. Seems like it would be easier to just go with a DC solenoid valve and go straight to the PLC.

leitmotif · Sep 11, 2012

Then give up on this manufacturer and pick someone else. There are multiple manufacturers of solendoid valves.

Dan Bentler

Solenoid valve conversion

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