A couple of years ago I bought an ex-school Union Graduate lathe. It was fitted with 2 foot operated stop switches presumably for use by a teacher overseeing a student although I never used them. I've really only just begun woodturning and using the lathe but last week I experienced some difficulty starting the lathe - pressing the start button produced a slight electrical noise but no rotation. Fearing the worst of perhaps a dead motor I decided to start by removing the 2 foot operated stop switches which were wired into the contactor switch (the electromagnet one in the base of the head stock). Mistake number 1 was not taking photos of the contactor switch. Mistake number 2 was to remove all of the wiring from the stop switch. Consequently I now have no idea how to rewire the switch. I have a wiring diagram for the 'standard 4 speed machine 230v single phase 1 hp' but what I could really do with is a photo of one correctly wired up. Can anyone help please? Roy.
Rewiring advice requested
- Thread starter Roy
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minilathe22
Established Member
Might be a bit tricky with your "custom" double foot switch... are you saying both switches need to be held down for the motor to start?
Does the foot switch have 2 connections? or 2 pairs of 2 opposite each other?
If it one in one out then all you do is wire the live input through the switch before it reaches the motor.
If its 2 pairs then you wire both live and neutral into the switch and then on to the motor.
Dont use the second switch at all
If it one in one out then all you do is wire the live input through the switch before it reaches the motor.
If its 2 pairs then you wire both live and neutral into the switch and then on to the motor.
Dont use the second switch at all
Thanks guys. Both stop switches were for emergency use to stop the lathe ie you only pressed them to stop the lathe. I have now removed and disposed of them both so the wiring should be able to be put back to factory standard. I have a friendly electrician looking at it on monday and will update you on my success or otherwise.
woodfarmer
Established Member
I am not noted for my adherence to all health and safety practices, but a well placed foot switch can be VERY useful. if you ever get into a situation with both hands in use and scared to let go and want the motor off. Make sure you can use it when close to the bed.
I installed a foot kill switch on my lathe, in contrast I removed the door switches off the crapomatic bandsaw as they never seemed to work for more that 2-3 sessions. Fortunately I have such good eyesight I can tell if the doors are open just by looking at them.
I installed a foot kill switch on my lathe, in contrast I removed the door switches off the crapomatic bandsaw as they never seemed to work for more that 2-3 sessions. Fortunately I have such good eyesight I can tell if the doors are open just by looking at them.
I like your comments woodfarmer. My friendly electician was on the task all day but it was not what you'd call a resounding success! Bypassing the usual on/off switches we proved the motor still runs ok and the wiring for the solonoid tested ok. So everything should work if we wire it up correctly. Obviously we have failed so far to do anything more than prove that my house fuses work. If anyone has any photos of a correctly wired contactor switch I'd be very grateful.
minilathe22
Established Member
I believe having the contactor between motor, power and on off switches is a fairly standard setup for many machine tools, I dont think it will be specific to the union graduate. Can you maybe find the spec sheet for the contactor you have online?
Phil Pascoe
Established Member
woodfarmer":oafctr6m said:
Not an answer to everything, but I wired my lathe with the power coming in through a cable outlet on the end of the bench then through another on the front then on to the main NVR so I can switch it off quickly and easily when long hole boring or when the head is turned. Simple and cheap.
hawkeyefxr
Established Member
You don't say if it has a capacitor or not, most large single phase motors have a run or start capacitor. If you can spin the motor when starting it may get away and run. Capacitors are easy to change.
Assuming there are no electronic controls on the motor....and its single phase,,,,,,,,
the live and neutral go to one side of the contactor, then on to the motor.
A live feed from the mains side goes to the on / off switch (if its an NVR switch live AND neutral go to the switch and then the neutral returns to main neutral).
live from the switch goes to A1 on the side of the contactor.
from the other side (A2 from memory) the wire goes to neutral.
Operating the on / off switch energises the coil inside the contactor which makes the contactor operate.
the live and neutral go to one side of the contactor, then on to the motor.
A live feed from the mains side goes to the on / off switch (if its an NVR switch live AND neutral go to the switch and then the neutral returns to main neutral).
live from the switch goes to A1 on the side of the contactor.
from the other side (A2 from memory) the wire goes to neutral.
Operating the on / off switch energises the coil inside the contactor which makes the contactor operate.
Bob
No disrespect but your advice above is hopelessly wrong
Live and neutral do indeed go into one side of the contactor
The output from the contactor goes to the motor....
Your words suggest to the motor from the input side.
A live feed does indeed to go to a switch but it does need to be a momentary push switch
The other side of the switch then goes to one terminal of a normally open set of contacts on the contactor which is also connected to a live feed
The other side of the set of contacts then goes to a normal closed switch ( the stop switch) and as many microswitches( all normal closed) as you want need then On to A1 on the coil
The a2 on the coil then goes to neutral.
So when you press the on button the coil is energised and pulls the contactor in the pair of contacts hold teh contactor closed until you break the circuit with a stop button or microswitch or power failure
This is how the graduate lathe works and you have a NVR mechanism as when the input power fails the contactor drops out and wont restart.
It isn’t good practice to switch a contactor with a on/off switch which is permanently on rather than as i described with momentary buttons and guard/door switches
Ian
No disrespect but your advice above is hopelessly wrong
Live and neutral do indeed go into one side of the contactor
The output from the contactor goes to the motor....
Your words suggest to the motor from the input side.
A live feed does indeed to go to a switch but it does need to be a momentary push switch
The other side of the switch then goes to one terminal of a normally open set of contacts on the contactor which is also connected to a live feed
The other side of the set of contacts then goes to a normal closed switch ( the stop switch) and as many microswitches( all normal closed) as you want need then On to A1 on the coil
The a2 on the coil then goes to neutral.
So when you press the on button the coil is energised and pulls the contactor in the pair of contacts hold teh contactor closed until you break the circuit with a stop button or microswitch or power failure
This is how the graduate lathe works and you have a NVR mechanism as when the input power fails the contactor drops out and wont restart.
It isn’t good practice to switch a contactor with a on/off switch which is permanently on rather than as i described with momentary buttons and guard/door switches
Ian
Ian,
I dont see how i could suggest feeding the motor from the in side of the contactor, thats nonsense.
The contactor needs a switched live to operate the coil inside it. If the lathe in question has a momentary switch on top of the contactor, thats a different wiring system to the one I proposed.
I spent many years on all sorts of commercial equipment with heaters and motors, and they were all wired the way i said.
I accept i do not know the lathe in question, but I take exception to the "hopelessly wrong" comment. If there is no electronics involved, i could wire that lathe as i suggested and it would work fine.
I dont see how i could suggest feeding the motor from the in side of the contactor, thats nonsense.
The contactor needs a switched live to operate the coil inside it. If the lathe in question has a momentary switch on top of the contactor, thats a different wiring system to the one I proposed.
I spent many years on all sorts of commercial equipment with heaters and motors, and they were all wired the way i said.
I accept i do not know the lathe in question, but I take exception to the "hopelessly wrong" comment. If there is no electronics involved, i could wire that lathe as i suggested and it would work fine.
Bob
How does this read?
“the live and neutral go to one side of the contactor, then on to the motor.“
I know i’m Being literal but you don’t suggest through the contactor
People will read your notes and if there’s opportunity to do something wrong it will be done.
So you happily wire a contactor in using a normal switch on/off maintained rather than momentary buttons?
How does this read?
“the live and neutral go to one side of the contactor, then on to the motor.“
I know i’m Being literal but you don’t suggest through the contactor
People will read your notes and if there’s opportunity to do something wrong it will be done.
So you happily wire a contactor in using a normal switch on/off maintained rather than momentary buttons?
minilathe22
Established Member
I think without knowing the exact circuit diagram of the contactor, we cannot be confident over a forum that we are giving solid and safe advice to wire this up properly.
You should be able to find a circuit diagram online if there is a part number on the contactor device itself?
You should be able to find a circuit diagram online if there is a part number on the contactor device itself?
Guys, please don't fall out over my stupidity. I'll get it sorted out eventually honest. To answer a couple of questions above, there is no capacitor and no part number on the NVR contactor device. The only wiring diagram I could get hold of is a generic one for the union lathe itself and nothing for just the contactor device fitted to the lathe.
I think I understand what you are both trying to explain and will have another go at it later this week. Thanks for persevering. Roy.
I think I understand what you are both trying to explain and will have another go at it later this week. Thanks for persevering. Roy.
Roy
Its a very simple thing to do really but its difficult to help someone at a distance.
The graduates were made over such a long time period that components changed designs manufacturers etc
So if your have a photo of one installation the chances of it being the same as yours is very slim
Half the problem is that as standard the installation at the base of the pedestal is cramped and difficult to get into so see where wires go
It may be best if you rip everything out and start again afresh
Get it working out of the machine and then place it in its box
If you can post a good clear picture of your contactor and overload(if fitted) I can respond with a simple diagram of where wires need to go
Maintaining your start /stop buttons and switches on top cover and belt change door
Ian
Its a very simple thing to do really but its difficult to help someone at a distance.
The graduates were made over such a long time period that components changed designs manufacturers etc
So if your have a photo of one installation the chances of it being the same as yours is very slim
Half the problem is that as standard the installation at the base of the pedestal is cramped and difficult to get into so see where wires go
It may be best if you rip everything out and start again afresh
Get it working out of the machine and then place it in its box
If you can post a good clear picture of your contactor and overload(if fitted) I can respond with a simple diagram of where wires need to go
Maintaining your start /stop buttons and switches on top cover and belt change door
Ian
I think I've added an image of the contactor switch. The wiring in the pic is one of my failed attempts to get it to work. By the way, some of you refer to contacts labelled a1, L1 etc. There are no labels on this contactor so I cannot make any of the connections using your otherwise very helpful suggestions. Roy.
Needs to be much much better than that
Its only 18k it can be 250k
And it would be best if it was on a bench on a piece of white paper with no wires connected
Ian
Its only 18k it can be 250k
And it would be best if it was on a bench on a piece of white paper with no wires connected
Ian
Also enough pictures so i can see every connection
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