how to wire relays

Thread Starter

to old

Joined Jul 28, 2021
8
hello , how would i wire relays to run my home made milling machine table to go in and out when on auto , here is what i have now .cross feed travels to the left hits a limit switch stops timer kicks in and puts24VDC to a wire that will feed the in /out action ,this happens at each end of the cross feed travel . the in/out motor is AC and reverses fine ,i have limit switches on both ends of the in/out travel which are NC ,it also must start from any position , i need a wiring diagram on how to accomplish this, i have lots of industrial weidmuller relays dpdt and 4pdt thanks from to old
 

Irving

Joined Jan 30, 2016
2,311
Just to be clear, you want it to bounce the table back and forth on the end limit switches on the Y carriage, and you want this to be triggered at the end limits of the X carriage? Is there any specifics on rate of travel i.e Y feed takes same time as X feed? Or does Y feed only happen at X end-limits?

Are your limit switches only NC or of the changeover variety?
 

Thread Starter

to old

Joined Jul 28, 2021
8
Just to be clear, you want it to bounce the table back and forth on the end limit switches on the Y carriage, and you want this to be triggered at the end limits of the X carriage? Is there any specifics on rate of travel i.e Y feed takes same time as X feed? Or does Y feed only happen at X end-limits?

Are your limit switches only NC or of the changeover variety?
moves in at x end limit to what ever timer is set at 1-4 sec. and then travels back on next cut ,and keeps going back and forth and moving in at the ends until job is done , the feed for the in /out is run by wire that comes from timers . the fellow who built the machine some 30 yrs ago is gone now. yes limits can be changed ,but they nc originally ,the circuit board was not repairable,so that part that controls in/out a bunch on relays is what we are replacing . ps i can make it work with only one wire to motor and therefor only one direction ,it looks like it took 5 relays to do it .thanks to old
 

MaxHeadRoom

Joined Jul 18, 2013
23,933
You didn't indicate your level of experience, but a nice clean way would be to make a sequencer with a Smart Relay, there are a few manuf.
This is a mini PLC. Includes timers etc.
 

Irving

Joined Jan 30, 2016
2,311
So the amount it moves in each pass is controlled by the timer, not by distance/DRO. I guess this is to do an automatic surfacing cut. My XY bed is driven by stepper motor so everything is done by steps, 1 step = 0.005mm
 

Irving

Joined Jan 30, 2016
2,311
You only want the table to move automatically in one direction, so as it traverses back and forth in X, it travels, say, front to back in Y and stops.... and this movement in Y is triggered by both of the X end limits. The X traversal back and forth on the limit switches,; is that working or was that also part of the dead board? If that's currently working, how is that achieved (circuit?)
 

Thread Starter

to old

Joined Jul 28, 2021
8
You didn't indicate your level of experience, but a nice clean way would be to make a sequencer with a Smart Relay, there are a few manuf.
This is a mini PLC. Includes timers etc.
hello i really want to keep all analog ,i have been a mechanic all my life to old now ha ,.as i am also a violin makers of some renoun this machine is a patographic router/milling machine gets rid of alot of exess wood .thanks
 

Thread Starter

to old

Joined Jul 28, 2021
8
You only want the table to move automatically in one direction, so as it traverses back and forth in X, it travels, say, front to back in Y and stops.... and this movement in Y is triggered by both of the X end limits. The X traversal back and forth on the limit switches,; is that working or was that also part of the dead board? If that's currently working, how is that achieved (circuit?)
just the in/out everthing else is great ,i iam a violin maker ,the machine is a pantographic router/milling machine .worked great beautiful machine ,i have been keeping it going all these years ,technically that in/out circuit is the same almost as the cross feed .thanks .to old
 

MaxHeadRoom

Joined Jul 18, 2013
23,933
the fellow who built the machine some 30 yrs ago is gone now. yes limits can be changed ,but they nc originally ,the circuit board was not repairable,
Did he leave any kind of drawings or sketches of the circuits etc ?
Did he make the circuit board up?
A photo of the M/C would also help.
 

LesJones

Joined Jan 8, 2017
3,571
Can you confirm that you already have the X axis (left / right) automatically traversing end to end with a delay at each end and for the duration of the delay it supplies a pulse of 24 volts DC ?
Do you want to add a circuit so that the duration setting of the delay controls the distance traveled in the Y direction (Front to back.) ? I am not clear if you need the whole circuit designing or just the Y direction part. Are we allowed to use any electronics (For example LM555 ) to create the delays or are we only allowed to use relays and large value capacitors ?

Les.
 

Irving

Joined Jan 30, 2016
2,311
Also, what is the voltage, current and HP or power rating of the Y-axis motor.

A schematic of the existing connections and a photo of the old control board might be helpful.
 

zophas

Joined Jul 16, 2021
156
A schematic of the existing connections and a photo of the old control board might be helpful.
Agree. Sounds like the system was working and then for some reason the y-axis board blew up. If we could see what was there we might be able to help. Also his reference to NC might mean Numerical Control and possibly not Normally Closed.
 

Thread Starter

to old

Joined Jul 28, 2021
8
Also, what is the voltage, current and HP or power rating of the Y-axis motor.

A schematic of the existing connections and a photo of the old control board might be helpful.
hello do not have any schematics for the machine ,old board is toast ,the in/out motor is ac not sure of hp. not a very large motor. all relays are operated on 24 vdc . thanks again to old
 

Thread Starter

to old

Joined Jul 28, 2021
8
Agree. Sounds like the system was working and then for some reason the y-axis board blew up. If we could see what was there we might be able to help. Also his reference to NC might mean Numerical Control and possibly not Normally Closed.
in this case nc stands for normally closed , lightning hit pole transformer ,thats what fried the y or in/out axis ,there is a way to wire those relays so it all works ,all done with relays ,thanks to old
 

LesJones

Joined Jan 8, 2017
3,571
A few more questions. Is the AC motor an induction motor that has three wires coming out from the windings and is there a capacitor connected between two of the three wires ? What are the controls like on the existing system, push buttons, toggle switches and what are the function labels against each one ? Is the timer for the delay at the end of the X axis travel adjustable and does the length of this delay control how far the Y axis moves at each end of the X travel ? (I.E Is the amount Y travel just controlled by timing ?
As others have said, some pictures may be helpful.

Les.
 

zophas

Joined Jul 16, 2021
156
in this case nc stands for normally closed , lightning hit pole transformer ,thats what fried the y or in/out axis ,there is a way to wire those relays so it all works ,all done with relays ,thanks to old
You mentioned a "1-4 second timer" is that also gone? It might help if we saw the existing working circuits so that we know what direction to take to try to help you.
 

MisterBill2

Joined Jan 23, 2018
9,844
Certainly it could be done with a PLC, either expensive or cheap (Automation Direct), but the TS has stated lots of relays on hand. Usually milling machine traverse motors are not very fast, and they have lots of gear reduction so they are not very powerful. Stepper motors do not seem like a best choice because they step. Tool marks would then be the result. A relay for each direction seems reasonable and simpler to check out initially.
 

Irving

Joined Jan 30, 2016
2,311
The TS has already said its an AC motor which is an unusual choice, but then the original owner was looking for traversal not positioning. It does sound like the original owner was a seat-of-the-pants engineer who could make anything work with whatever he had lying around (so kudos to him).

Stepper motors do not seem like a best choice because they step. Tool marks would then be the result.
Not a CNC machine user then MrB? Stepper motors are the most common form of motive force for axis motion in small to medium size-machines. My CNC mill and lathe both use steppers. They are relatively cheap yet powerful, easy to drive and position. A typical stepper steps 200 to 400 steps per rev and with the right controller can microstep 8 or 10 steps between the major ones, giving 4000 step/rev or more. Coupled with a suitable leadscrew or toothed belt drive resolutions of 10um are not uncommon and as low as 0.5um are possible. You won't see tool marks...
 

MisterBill2

Joined Jan 23, 2018
9,844
The TS has already said its an AC motor which is an unusual choice, but then the original owner was looking for traversal not positioning. It does sound like the original owner was a seat-of-the-pants engineer who could make anything work with whatever he had lying around (so kudos to him).



Not a CNC machine user then MrB? Stepper motors are the most common form of motive force for axis motion in small to medium size-machines. My CNC mill and lathe both use steppers. They are relatively cheap yet powerful, easy to drive and position. A typical stepper steps 200 to 400 steps per rev and with the right controller can microstep 8 or 10 steps between the major ones, giving 4000 step/rev or more. Coupled with a suitable leadscrew or toothed belt drive resolutions of 10um are not uncommon and as low as 0.5um are possible. You won't see tool marks...
NO, I am not a CNC machine user. I can run a manual mill well enough to make parts to the drawing dimensions and do it without melting tools or leaving serious tool marks. Not as fast as a certified and well trained machinist but adequate for many prototype purposes. The CNC machines were reserved for production runs and others did that part.
AND I have designed steppers into quite a few machines, and always been aware that at lower speeds they were stepping, not spinning smoothly. And I know hat they do not work well for spinning a platter to play records, at least not in the full step mode.
 

LesJones

Joined Jan 8, 2017
3,571
I don't think the TS is worried about surface finish from the last sentence in post #7 "milling machine gets rid of a lot of exess wood " I think is just used to remove a lot of material.

Les.
 
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