Please help modify this estop circuit 1

[jw007]

Please see the attached schematic image.
I am looking for help in changing this to work on a wiring system that does not include the neutral on the 220 feed input.
I highlighted the line in red. I realize the relay uses a 110v coil, but I could replace that with another type, possibly a 24volt.
I was thinking that I could pull the 24v output from the powerflex but wasnt sure if that would work right. If not anyother ideas?
Thanks

http://files.engineering.com/getfil...12-8a51-077b49abc713&file=Mill_Schematic.jpeg

 

[Compositepro]

Why would you go with 24 volts? Replace the relay or coil with a 220 volt one and connect the wire that is now on the neutral to an appropriate 220 volt phase wire (not R). That is assuming your schematic is complete and correct.

 

[ScottyUK]

So many reasons not to use 220V control, safety being the first one that spirngs to mind.

 

[jraef]

You cannot pull the 24VDC from the PF40 terminals, unless you like buying new PF40 drives a lot. That internal power supply is capable of feeding it's own input transistors, not much else else. Maximum output current is 100mA, but you still can't use it all without compromising your inputs.

Also, assuming you are in the US somewhere by virtue of you discussing 110V control, and given that the breakers used in that (Siemens SQ23) are not legal to use in the US, the chances are high that this was designed and built in some other country, where most likely that is NOT a 110V coil, but rather a 220V coil, on a machine designed to be fed with 380V 50Hz where the Line to Neutral voltage is 220V. If it were modified to supposedly work on a US 230V 3 phase system and they put in a 110V coil, someone did not understand the differences here. 230V 3 phase here is not Wye, it is always Delta, so there is no L-N 110V inherently in the design. There is a POSSIBILITY that you have what is called a 120/240V 3 phase 4 wire system, also called a "High Leg" or sometimes a "Red Leg" 230V delta system. In that system, one leg of the 230V delta transformer, usually phase A-C, is center tapped to give you 120V from A or C to Neutral. But if you are saying that you have no Neutral feed, then you don't have that. So your only choices are to 1) get a 230V 60Hz coil for that relay and run 230V to your control devices, or 2) get a separate 230V power supply that gives you 24VDC output for that circuit. I would go for the 24VDC power supply.

Either way, you will have to change the coil on that relay, and that's the other bad news. That relay has been out of production and support by Siemens for well over a decade, actually longer than the PF40 has been around, which means someone cobbled this together with old parts (or that it originally had a different VFD). So your only hope of finding a different coil voltage for that is going to be E-Bay or other surplus parts dealers. If it were me, I'd just replace the entire relay, it will likely cost you less.

"Will work for (the memory of) salami"

 

[controlsdude]

Hard to tell what is 3 phase, control power, and your estop circuit.
No wire numbers, I am used to either single line or ladder wiring diagram and sad to say that is neither. This is not even JIC or IEC standard diagram, you need to draw to a standard, not some ""etch or sketch" diagram.

But basically a PF40 you pull the enable contact and/or in conjunction with your safe off if your drive is that later model.

 

[waross]

You could put in a control power transformer

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jw007]

Jraef - You are correct on all points. This machine was built in india, originally as 460v. I replace the VFD and swap the motor wiring to work on 230.
I will be using a 24v external ps & replacing the entire relay, as you suggested. Since the ps will only be operating the coil, I assume any should work, but I would like to use this inexpensive 24v, 2.5amp unit
I appreciate your help very much. As well as all of the comments.
I am trying to learn how to draw ladder diagrams using ACAD E. The etch a sketch comment made me laugh.

 

[LionelHutz]

Just do what Bill posted. Use a control power transformer to get the required control power.

 

[jw007]

Does a control relay need a set of fuses for it?

 

[waross]

You may purchase control power transformers with a secondary fuse mounted or with a secondary fuse and two primary fuses mounted.

Bill
--------------------
"Why not the best?"
Jimmy Carter