Thread: Do you think I damage something?

I cant figure out your button pressing in the second test, the start button would have started it but I cant see how it would have kept running once you let it go. Maybe I'm missing something.
I doubt you've done the motor any harm, but I wouldnt know that either.

You've got to be lucky now and again

Stuart

Mate ... Can't read your diagram on my iPhone but will do so tomorrow. But once you press the start, the contactor closes, and now the auxilary contact (the one that is not coloured in like the other 3) closes, bridging out the start button and holds the contactor in ( the start button is now out of circuit) .. The contactor will not fall out now until the stop button is pressed ..

if you don't follow this, wIt until tomorrow until I can see the circuit clearly on a laptop.

cool bananas ... Greg

I too think you got away with it

To change motor direction, just swap any two of the three phase wires to the motor. Doesn't matter which ones. In your case you can even do that anywhere along the 3-phase connections - even at the switchboard end.

Hi Camo,
a most exciting evening
Firstly, I doubt that any damage has been done. A mega test will soon tell you if the motor is ok.
Secondly, I don't think your recollection is correct. It should have stopped as soon as you took your finger off the start button. The button may need replacing if that is the case as it could be sticking.
Thirdly, if the contacts are closing under gravity alone then the contactor needs replacing. The contacts should be held apart under spring pressure and should not move until power is applied to the coil. I would be replacing it with a new contactor. Make sure you ask for a 415V coil. A 20A rated contactor will do the trick. It may also explain the phasing you witnessed if one of the main contacts is sticking or the spring is shot.
To reverse the motor swap A2 and B2.

Hi all,

Thanks all for your fast replies. I think what I was definitely experiencing in the second event (after switching the wires), was the motor only momentarily starting, and me thinking I was turning it off with the off switch (I wasn't turning the motor on for very long and then turning it off), so I think I just thought I was turning the motor off, but in fact it was already slowing down once I took my finger off start.

I don't have access to a mega tester unfortunately, but would I be right in thinking that if I have done damage, that the damage is done, and the worst that can happen is that the motor burns out completely and I have to replace what I would have had to replace anyway, or is there an in-between save if some damage is done (I wouldn't like the idea of taking the motor back out to be tested, the motor alone is not light and I have to take the table off to get to it, and the table would have to be at least 300kg)? Unfortunately this is not your average 3 phase motor, the main shaft of the motor is also the arbor for the blade, so I can't just switch the motor if something is wrong, so I could really use some advice on if what is done is done, do I need to have it checked to save bigger expense in the future.

I wanted to try to stay original with the contactor if possible, I actually have two identical contactors (the second is in my Stenner spindle moulder). I had a look at both and the springs in them (actually now I look under better light the spring does nothing, but resist gravity a bit, I think, it all works under gravity) seem to be holding back the contact the same amount (they don't touch under gravity, and they certainly work properly in the correct orientation). It is effectively one big 4 pronged hand, (perhaps I should take a picture tomorrow), I am thinking (hoping), that it was just the combination of laying it down and also laying it on an angle that caused it. The tests I did when the contactor was in the correct orientation and bolted back on, were short starts maybe 3 seconds, followed by turning it off and letting it come to rest, and then start again and it seemed to run correctly (except the fact that it ran backwards, but as you guys have pointed out, that is an easy fix).

Cheers,

Camo

Being a 1957 machine and if it has all the original equipment, it sounds to me like the contactor might be something similar to the old Nilson's AD40 contactors. From memory, they had a range of them - AD35's, AD40's and AD65's (although, I may have got numbers wrong, but were AD something's). Huge beasts that were about the size of 2 bricks put together.
They were strictly vertical mount contactors because there were no release springs to drop out the contacts and we had huge dedicated contactor rooms with wall-to-wall contactors.
Everything was done via gravity and if mounted horizontal, the weight of the contacts, contact arm and coil poles would close the contactor.

I haven't seen one in 30 years, because they were getting phased out in around the mid-70's, probably earlier, in favour of the smaller spring loaded contactors that are around today.

To change overload size, you would need to unbolt the heater coils (literally, a coil of wire that looked like a flattened spring with a couple of tabs on each end), pull out the overload arm (a bi-metal strip that would bend depending on how hot it would become from the o/load heater) and put in the new overload arm.
The AD65 star-delta starters were a wonder of engineering with two AD40's wired to suit, but with an oil filled dash-pot timer for the changeover sequence. From memory, you would adjust a knob on the timer to adjust the oil flow through a hole in the oil pot, and this would regulate the speed at which the timer would operate. Every now and then, you'd need to do a service on them, and refill the oil pot because the oil would sweat out.

Great contactors for an apprentice to learn on. Terrible contactors to use on electrical work.

Camoz .... This is the schematic of the 'diagramatic' you posted. It is exactly the same drawing but drawn in ladder logic.



How it works.

You press the Start Button.

The Contactor C is immediately energised

The Contactor C closes the contacts C1, C2, C3, AND C4

The Contact C4 bridges out the Start Button, which is now no longer in circuit.

The Contact C4 (known as the auxiliary) now holds the Contactor C in the energised state. A bit like holding yourself up by your bootstraps. I hope you understand this bit ?

The ONLY way to now de-energise the Contactor C is to press the Stop button or trip the Overload Switch


C1 = L1 in your drawing
C2 = L2
C3 = L3
C4 = the contact with the numbers 1 & 2 against it.

The dotted line is the alternate wiring if you do not have a control fuse. In your drwg you do not.


I really hope you understand what I am saying here .... DO NOT play with 415v ... it will KILL you in milliseconds. It is pretty obvious that you DO NOT know what you are doing. No offence meant at all ... just concern

Greg

Originally Posted by Mutawintji

Camoz .... This is the schematic of the 'diagramatic' you posted. It is exactly the same drawing but drawn in ladder logic.



How it works.

You press the Start Button.

The Contactor C is immediately energised

The Contactor C closes the contacts C1, C2, C3, AND C4

The Contact C4 bridges out the Start Button, which is now no longer in circuit.

The Contact C4 (known as the auxiliary) now holds the Contactor C in the energised state. A bit like holding yourself up by your bootstraps. I hope you understand this bit ?

The ONLY way to now de-energise the Contactor C is to press the Stop button or trip the Overload Switch


C1 = L1 in your drawing
C2 = L2
C3 = L3
C4 = the contact with the numbers 1 & 2 against it.

The dotted line is the alternate wiring if you do not have a control fuse. In your drwg you do not.


I really hope you understand what I am saying here .... DO NOT play with 415v ... it will KILL you in milliseconds. It is pretty obvious that you DO NOT know what you are doing. No offence meant at all ... just concern

Greg

Greg,

No offence taken, my actions have spoken for themselves (had I had the knowledge, I would have known that switching the two wires would not be the answer), and I would not have asked the question if I knew what I was doing (as I would know what damage I could have done), but you are right to point out that I should not have played with it. This is normally something i factor into the cost and get the electrician to play with, which I did in this case, but could not test it at the time. Generally I need to have the earth connections upgraded from mechanical anyway in these old machines. The only thing I would like to say in my defence is that without going into great detail, I followed some fairly strict procedures (some might say extreme to the ridiculous precautions) to ensure that I was not in personal danger (my father worked in electronics and as an electrician and always said treat everything as if it is live, and an idiot has wired it up, to this day even with new equipment I find myself touching the body of the machine with the back of my hand first).

Thanks for the explanation, I believe I had worked out the process eventually, this is why I think the angle I had the contactor on was the key, if I understand correctly, if it was laying flat, all four fingers would have made contact, and the motor would have started as soon as I turned the power on (gravity doing the work instead of the energised contactor). With it on the tilt C4 was permanently connected, so the coil was energised as soon as I released the stop button to its NC state. I am thinking that with all the starts and stops, that when I changed the wires, which had no net effect other than to turn it into a momentary motor (start and stop with the push and release of the start button), that say some but not all of C1,C2,C3 were not released when the coil was no longer energised, resulting in the fault that I experienced.

This is a picture of the "two bricks put together", it is actually the one from the Spindle moulder, which is yet to have been rewired:

image.jpg

I guess the only question I need to know now is do I have to get the motor tested, or just run it and hope for the best (ie. if I have done any damage, the repair is the same as if I keep using it, and it eventually fails)?

Part of me would like to go back and never list this question (pride), but I think the point of the forum is to help when you can and seek help when you need it, I appreciate people not absolutely brutalising me in the responses (although perhaps to an extent I would deserve it, I think I became the idiot my dad was referring to).

Cheers,

Camo

Hi Camo ... Busy at work this second but will get back here in my smoko break ..

cool bananas ... greg

Hey Mutawintji,
Mate your drawing is not the same.
The fuses in the original are in the mains
There is no neutral, it has a 415V coil.

For what it's worth

Thanx Duke ....

The 'Neutral' is just returned to another phase then ..and it is a schematic, so the fuse location is normally drawn as I have because multiple circuits come off the mains which would normally show a circuit fused breaker.

The logic of the schematic still remains the same for diagnostic purposes.

But your point taken, and for the non-controls-tech it could be misleading. Sorry ... will correct.

Greg

Originally Posted by camoz

image.jpg

I guess the only question I need to know now is do I have to get the motor tested, or just run it and hope for the best

Camo .... I do not fully understand your explanation of what you did ... But if the motor attempted to slowly turn, or hovered between back and forth, making grunting/humming' noises .. then you have managed to '2 phase' it.

Normally when a motor has dropped a phase (blown a single fuse) it will steadily hum, or continue to run but with vastly reduced power. A simple test (but dangerous .. I do not recommend it !!!) is when you start it and it hums is to give the shaft a spin ... if the motor spins up it is usually running on two phases only.

But if you have altered the wiring in the terminal cover of the motor, then you may have reversed the polarity of one phase .. in which case two sets of windings will be trying to drive the motor in one direction and the third set in the other. This is NOT the same as reversing a 3 phase motor by swapping two phases. It is a reversal of the polarity of one set of windings.

To fix this would be very difficult by text. But if you have done this, and as long as the winding wires emerging from inside the stator to the terminal block are labelled, A1, A2, B1 .. etc .. then I can do it over the phone for you.

But my guess is that you have not harmed the motor and all will be well. Motors can be rewound so even at the worst it is not a big problem. Hand wound motors are usually much better than the machine wound originals. So a rewind will actually give you a better motor anyway.

If you are concerned in any way, but determined to proceed without your electrician then you can phone me on 0429 505 111 and I will do my best to help and SAVE your LIFE .. tho even in these modern days, CPR is not so successful over the phone ... HaaHaa

cool bananas ... Greg

The circuit diagrams above are correct for DOL (Direct on line) Starters with 240 volt coils.

For DOL starters with 415 volt coils the following circuit is correct.



cool bananas ... Greg

Originally Posted by Mutawintji

Camo .... I do not fully understand your explanation of what you did ... But if the motor attempted to slowly turn, or hovered between back and forth, making grunting/humming' noises .. then you have managed to '2 phase' it.

Normally when a motor has dropped a phase (blown a single fuse) it will steadily hum, or continue to run but with vastly reduced power. A simple test (but dangerous .. I do not recommend it !!!) is when you start it and it hums is to give the shaft a spin ... if the motor spins up it is usually running on two phases only.

But if you have altered the wiring in the terminal cover of the motor, then you may have reversed the polarity of one phase .. in which case two sets of windings will be trying to drive the motor in one direction and the third set in the other. This is NOT the same as reversing a 3 phase motor by swapping two phases. It is a reversal of the polarity of one set of windings.

To fix this would be very difficult by text. But if you have done this, and as long as the winding wires emerging from inside the stator to the terminal block are labelled, A1, A2, B1 .. etc .. then I can do it over the phone for you.

But my guess is that you have not harmed the motor and all will be well. Motors can be rewound so even at the worst it is not a big problem. Hand wound motors are usually much better than the machine wound originals. So a rewind will actually give you a better motor anyway.

If you are concerned in any way, but determined to proceed without your electrician then you can phone me on 0429 505 111 and I will do my best to help and SAVE your LIFE .. tho even in these modern days, CPR is not so successful over the phone ... HaaHaa

cool bananas ... Greg

Greg,

Thanks for all your help. No need to help me with assisted suicide. As stated, I have returned the wires back to the spots that the electrician had them, I don't think the electrician has done anything wrong with the motor wiring, as it does not have a box, three wires just literally go into the motor and go straight into the windings, he just added an earth.

I just went out and tested it, (5 runs of 5 minutes, leaving it to come to a stop after each test with the motor turning in the correct direction) and it seems to be working fine, in fact it is bloody beautiful. I haven't had a chance to run this motor except for a short burst before dismantling, and I am amazed by how quiet and smooth it is (I have not attached the 18 inch blade yet), but I am very excited.

I can totally understand how you would be unsure what happened, given my poor explanation of the events, basically because even now, I am not too certain I can trust my memory of the events, everything just seemed to be going fine and then the motor did something that was not right (I can't even be sure if it was when I pressed the green button, the red button, while the motor was slowing or while it was winding up to speed), it was literally no more than probably 1 seconds and my focus was on cutting the power, followed by me cursing at myself for being so stupid.

I goggled the Megger testers, thinking if I had to, I would buy a second hand one, do the testing and then re-sell it again, but even those sound potentially dangerous.

I will try the spin test....should I remove the blade first.

Thanks again guys for all your help.

Now I just have to hope this post fades away in the background where no one can see it (147 people already know I am an idiot and counting).

Cheers,

Camo