Contactors

[RP Designs]

Ok, I am in the middle of tearing out the old Fanuc control for my retrofit and I am trying to identify the contactors. I need to figure out which contactor is the E-stop and which is the flood coolant. The old control used to control the power drawbar, flood, mist and probably a couple other things I can't remember. There seem to be five or six contactors in the cabinet and I don't have a good schematic to sort out which is which. Forget chasing down the wiring, that would have been an impossible task!

I have pulled one contactor out of the cabinet, it is a Fuji electric SRCa 3631-0(3a1b). They are all marked 110V in ink (I presume this was done when the control was first fitted). Two of the Contactors have a second piece piggybacked and have a dial adjustment on the front marked ARC 0.95 1.2 and 1.45. The connections are numbered 1,2,3,4,5,6,13, 14 (coil). This doesn't seems to correspond to the wiring schematic which has them labeled L1, T1 A1 etc.

First, can you help identify which is the e-stop contactor? What info can you give me on these? what is the little dial for? And what is the convention for naming terminals? Any help would be appreciated. here are some pics of what I've got:





I did try googleing the part number but not much info available.

[Al_The_Man]

The dial is a motor thermal overload, the large contactors look like they are set up in a reversing arrangement as the outputs (bottom connections) are coupled.
Anything with an overload on it controls a motor load.
M1-M2 are reversers.
If you are retro-fitting for a new control and do not have existing prints, It is a question of wire tracing to find out what is what, sometimes in a case like this it is best to come up with your own schematic and start over.
The contactors usually have a power or size rating marked on them.
BTW, yellow for control is the wrong colour code, this indicates that the power for this circuit originates from another enclosure and may be live when the disconnect is off.
There is no real convention when numbering terminals, however the U,V,W, usually represents a motor feed.
Al.

[RP Designs]

Everything is yellow in there! All of the wiring is what came with the original Fanuc control. I have a schematic for the new control, but nothing substantial for the old control. I have the owner's and maintenance manual but the closest it comes to haveing a wiring schematic is a block diagram and those don't even show any of the contactors.
What I show in the new schematic is a contactor for the e-stop (which I would like to try to re-use, but i am not opposed to starting clean slate) and a contactor for the flood coolant. I don't plan on running the drawbar through the control since it really is one button to push, and for the sake of simplicity it doesn't make much sense to add it. Mist coolant will also be manual since it really isn't that messy or tough to deal with, but i do want to keep flood cooling automatic.
What should I look for on the contactors to make sure they will work?

[123CNC]

In all the contactors you have pictured they appear to be labeled M1, M2, M6 - M9, a safe assumption motor 1, motor 2, etc. It is also quite common to have a label on one of the sides giving its rating, often with voltages and single or three phase loads and even hp rating. Usually also with terminal designation and also coil voltage. The 110V label you mention is likely the coil voltage required. Often times the extra contacts may be used as a status input to a PLC or controller or used to route conventional relay logic.

M6 has an overload mounted to it with adjustable amperage setting, 0.95 A, 1.2 A, etc. This was probably supplied mounted straight from the OEM and would be suitable rated for the contactor it rides on.

M1 and M2 or M8 and M9 appear to be your reversing contacts for the spindle and ??. Do you have a motor controlled spindle speed adjuster or motor driven drawbar?? My guess M6 is for coolant pump.

M7 looks the largest and is likely the MAIN contactor and could be tied into an E-Stop loop. You might try to trace the line side to see if they originate at your mains connection.

L1/L2/L3 often used to designate line or supply side and T1/T2/T3 terminal or load side. Common for naming the lines, not necessarily the terminals. Terminal numbering or naming is often a vendor convention. Not everyone agrees to conventions.

Looks like Al and RP finished this conversation faster than I can type.

[RP Designs]

Originally Posted by 123CNC In all the contactors you have pictured they appear to be labeled M1, M2, M6 - M9, a safe assumption motor 1, motor 2, etc. It is also quite common to have a label on one of the sides giving its rating, often with voltages and single or three phase loads and even hp rating. Usually also with terminal designation and also coil voltage. The 110V label you mention is likely the coil voltage required. Often times the extra contacts may be used as a status input to a PLC or controller or used to route conventional relay logic. M6 has an overload mounted to it with adjustable amperage setting, 0.95 A, 1.2 A, etc. This was probably supplied mounted straight from the OEM and would be suitable rated for the contactor it rides on. M1 and M2 or M8 and M9 appear to be your reversing contacts for the spindle and ??. Do you have a motor controlled spindle speed adjuster or motor driven drawbar?? My guess M6 is for coolant pump. M7 looks the largest and is likely the MAIN contactor and could be tied into an E-Stop loop. You might try to trace the line side to see if they originate at your mains connection. L1/L2/L3 often used to designate line or supply side and T1/T2/T3 terminal or load side. Common for naming the lines, not necessarily the terminals. Terminal numbering or naming is often a vendor convention. Not everyone agrees to conventions. Looks like Al and RP finished this conversation faster than I can type.

I had a motor controlled spindle speed adjuster, which I am removing in favor of a VFD. The motor designation helps, I only wish I knew which motor was which.

[Al_The_Man]

If you have nothing in the way of drawings, I would get hold of a copy from a comparable machine to use as a guide line, you will find very little in the way of control prints in Fanuc manuals, apart from the connection manual.
The MTB is responsible for control schematics.
The E-stop relay is not necessarily a heavy duty contactor but a multi-pole relay that drops out the relative control voltage, all it need to do is to control the power to the outputs and contactor coils, and a contact into the PMC/PLC to advise the control of the E-stop.
IOW, the E-stop relay does not usually control heavy 3 phase power on its own contacts directly.
You may be able to identify which contactor is for which motor by the size of the overloads and comparing with the size of the motors.
Al.

[123CNC]

Al makes a clear point.

I did not mean to imply that the largest contactor by virtue of size implies that is an E-stop contactor. Without schematics or tracing everything is conjecture.

Would also like to clarify that if it is used in the E-Stop loop, that it would most likely be activated/deactivated by dropping the coil, just as any other motor contactor. It isn't an unheard of practice to drop all high power as well as downstream motors served by high voltage if the high voltage/high amperage is one of the potential hazards you want to mitigate with an E-Stop.

It is also fairly common to leave low voltage and control voltage live in an E-stop to maintain PLC/Controller power. Although the safest 'E'-stop would de-energize all potential hazards.

Aside from schematic or tracing, starting over can be a good place to start.

[RP Designs]

Well starting over is the way I am leaning. I'm just not sure how to select a contactor. I've found other references for selecting components based on amperage or voltage requirements, but I haven't really dealt with contactors so I don't know where to start. What information do I need to specify the correct contactor?

BTW, I have no idea what coolant pump I have. It seems to be buried in the bowels of the machine and there isn't any access panel or anything with regards to the flood coolant.

[Al_The_Man]

Contactors are sized in voltage/H.P. generally and contact current rating, most now are DIN (European) style and smaller than the old NEMA rated type.
You should be able to pick up a catalogue or two if you visit the local Electrical wholesaler.
And practically everything is DIN rail mounting now, this makes for simpler installation.
Coolant pumps are generally not that large, I would not expect anything over 1/3hp.
As suggested, for E-stop I would just drop out the motors and output power, I use 24vdc for all inputs and indicators and leave anything that does not cause a saftey hazard, remain under power.
BTW, one reference that is handy is the NFPA79 Electrical Standards for Industrial Machinery, available from the NFPA by mail.
It also shows control wiring examples.
Al.

[RP Designs]

I did manage to find a good article on wiring the Fuji contactors for their different configurations. They do however list the contacts as L1,T1, A1 etc. I am guessing that the 1,3 and 5 terminals on the top correspond to the line terminals (L1,L2,and L3) and the 2,4,and 6 terminals correspond to the load terminals (t1,T2,andT3) and the 13 and 14 terminals correspond to the A2 and A1 poles respectively. Also there are two other connections marked simply as P one on each side caddy corner to each other. The only thing I can figure out is that these are the 53 and 54 leads which the switch gets wired through.

Here is the document I was looking at:
http://support.automationdirect.com/docs/an-mc-004.pdf

Also looking at the sticker on the 14 terminal it appears that the coil is a 200-240V 60 Hz which leads me to assume it is a 220Vac contactor. As far as the current rating, does that apply to only the coil or does that apply to across the terminals (or both)?

[Al_The_Man]

L1,L2,L3 etc are generally the 3 phase in, the A1 A2 terminals are the coil.
The coil voltage has nothing to do with the current/voltage rating of the contactor itself.
The current rating of a contactor is for the switching contacts, you will find that most not only have the contacts for three phase but also auxiliary contacts required for coil interlocking purposes for example when reverser's are used and this prevents two contactors picking up at the same time.
In your picture it also appears that at least a couple of the reversing contactors are not mechanically interlocked, this can be a problem even when electrical interlocking is done.
It is current practice to buy a pair of contactors that are interlocked mechanically when used as motor reversers.
Al.

[RP Designs]

So the e-stop contactor that is called for in the schematic is a 4 pole 24Vac coil. L1 is connected to the supply and T1 goes out to the motor voltage input on the controller (+Vm). L2,L3,T2 and T3 are not connected. L4 comes from the Spin Res Com port on the controller and T4 goes back into Spin En Com.

At this point I am probably just going to buy a couple of new contactors. I found a bunch of three pole contactors but haven't found a good source for four pole contactors. Are the other poles is a three pole contactor independent? What I mean is can I use a three pole contactor and connect L1 to T1 as the schematic shows and then use on of the other terminals to connect the Spin Res Com port to the Spin En Com port?