3 pole contactor trouble. 230 v coil, 50hz. ADVICE PLEASE

[malcolmsanford]

You could use the a bit of the plank to wedge the contactor in.
Sorry
BTW it wont be the first time a bit of wood has been used to wedge a contactor in

Always found that a torn off piece of a Senior Service ciggie packet was a good DOL accessory.

 

[wade88]

speaking of DOL's chaps,

having wired the new one in, and energised the system and pressing the starter, it has blown the switch inside... im only running a 0.25kw motor and its a 4a contactor block. On the stop side, there is a no-volt switch installed also. I have just ordered some new contactor blocks from RS and waiting there arrival but could someone gve me any clues as to why this may be happening?

 

[netblindpaul]

You get a plant that’s costs £20K an hour shut down it’s surprising what you’ll do

Only £20k per hr!
I was once the subject of attention as I was working on a breakdown on a machine which was stopping their customer plant, which back in 1998 was being back charged at over £110k per hr!
I was changing serious mechanical parts on the machine with BIG machine assemblies hanging on a crane with a driver sat in it engine running, machine on, hyrdaulics on, plc on, cnc on, pneumatics on!
I had the plant manager running around buying me (& paying for) my cups of coffee, I could have as many as I liked as long as I kept working!!!

 

[silva.foxx]

Wade88 - I know you said you're a newbie but you come across as less competent than the 'metal worker' who installed it.

You have 3-phase supply... yes?

You have a 3-phase motor... yes?

You have IR and ohmically tested the motor and it is fine... yes?

You have 3 wires of the 3-phase supply into the top of the contactor... yes?

You have 3 wires into the bottom of the contactor and out to the motor... yes?

You have disconnected all control wiring and pushed the contactor in manually... yes?

You have traced out your control circuit... yes?

So you will have a normally open pushbutton, a normally closed pushbutton, a thermal overload (terms 95 & 96) and you will utilise the volt-free contact (auxiliary) of the contactor as your hold-on latch.

You will take a wire from one of the top wires (perhaps L1) out to the 95 of the overload. Out of 96 to the normally closed pushbutton. Out of the normally closed pushbutton to the normally open pushbutton. Out of the normally open pushbutton back to the contactor coil A1. We will come back to the normally open contact shortly.

Now take a wire from one of the other wires (perhaps L3) and take that to the contactor coil A2.

If you power-up now... by pressing the normally open pushbutton the contactor should energise, close thus power the motor. If all is well at this time then you're nearly there!

For god's sake... power off before this next bit!

Back to the normally open pushbutton. You need to wire the contactor auxiliary in parallel to this...ie. place an additional wire to one side of the normally open pushbutton and connect to one side of the auxilliary contact. Place an additional wire to the other side of the normally open pushbutton and connect to the other side of the auxilliary contact. This will then allow your contactor to latch in.

If this fails... get the metal worker back

 

[wade88]

Silva,

Cant thank you enough mate for the helpful reply. Haha yes, he certainly knows how to make something work, his methodology is just a bit off ( using CPC's as live conductors etc), however well and truly humbled all the same...thanks for highlighting that

I shall hop to it and follow these instructions. if i break everything again...ill find you.

Thanks bud

B

 

[wade88]

Silva...or Fox which ever you prefer...

Another brief question to further waste your time, how do i wire the safety cut out switch then? the instructions you kindly gave me are brilliant, althought i feel in hind sight i may have misled everyone a touch. The contactor is seperate from the switch gear which is 4 meters away or so. the stop/start button and motor power are fed with SY cable and run back to the Contactor box. the start/stop is powered via a 3 phase commando fed from the SY run on seperate cicrcuits....im awful at expaining a picture at this point would be infinitley useful but im not sure how to do that.

And so i have a DOL on my desk in front of me with the start stop functions directly incorporated into the contactor with thermal overload attachment. I can only assume that your installation instructions remain the same, the only difference being the stop/start and safety cut out are actually several meteres away from the contactor. Excuse me drivelling on in absolute lamens terms here but i need to get head around it.

 

[silva.foxx]

It's not a waste of my time or anyone else who chips in here, it's what the forum is for, and if it's a help to you it'll be a help to others... perhaps.

First off... please define your 'cut-out' switch

Do you mean the overload contact? The unit at the bottom of the contactor?

I'll add some drawings...

 

[silva.foxx]

Above is how your power to the contactor should look along with the tails out to the motor from the bottom of the contactor/overload.

Now... we'll do this slightly different to how I initially stated...but simpler.
You stated it was a 400v coil. Take a feed from L3(T) to the auxiliary contact and take a feed from the same terminal of the auxiliary contact through the commando socket, then plug and into the start button contact.

Take a wire out from the other side of this start button contact to the stop button contact. A further wire is to go from this same terminal of the start button contact back to the contactor via the commando plug and socket to the bottom side of the auxiliary contact.
Also a wire is to go from the other side of the stop button contact via the commando plug and socket to terminal 95 of the overload (which is what I'm assuming you refer to as 'cut out' switch.

Take a wire out of terminal 96 of the overload to A1 of the contactor coil... A2 may be easier but ensure you do not use the same designated terminal again.
Finally take a wire from A2 (or A1 if you used A2 from terminal 96) to L1(R) to complete the circuit.

Ensure you use the commando socket on the contactor side of the control so you don't expose any live parts!

Earthing to be completed between the four devices... not shown in the diagrams.

Here...endeth the lesson.

God help us all if this fails now!

 

[Jurasic Spark]

Very good explanation of how to connect the D.O.L. I know everyone has to start somewhere and we all learn something new from time to time but I find this thread a little disturbing. I could get a none electrician to follow your instructions without problems but would they understand why it was wired that way? No disrespect meant to anyone but there is a statutory requirement for competence:

Persons to be competent to prevent danger and injury

16. No person shall be engaged in any work activity where technical knowledge or experience is necessary to prevent danger or, where appropriate, injury, unless he possesses such knowledge or experience, or is under such degree of supervision as may be appropriate having regard to the nature of the work.

The Electricity at Work Regulations 1989

 

[silva.foxx]

Agreed JS.

I'm sometimes a little overzealous!

Mods: Please feel free to delete post#26 if it's a cause for concern, in the interest of responsibility.

 

[wade88]

Hi guys,

I would just like to raise the point that i am fully aware of my limitations concerning three phase stuff and hence the reason i have actually left it to be done by someone who knows how. i am simply here asking the questions now to learn and better my understanding of what to do and how to do it for future reference. i certainly have no intentions of turning myself into a 6ft2 strip of beef jerky so figured i would stay out of it.

Many of my posts may appear to many as "this guy should be back at college" but i find it easier to learn talking to you guys on here then i do nose down in a, lets be honest, pretty dry read...although i do of course read the books as its fairly essential. Nevertheless, i hugely appreciate the input and that last post Silva was of a great help to me so a big thanks mate. I send you a cyber pint to enjoy at your will!

Cheers B

 

[silva.foxx]

So... have you done it yet?

 

[wade88]

No ive been stuck at my desk this morning sorting some other bits out but after my lunch i will have a go! I shall be sure to keep you updated on my progress. I guess your very curious to see how this all pans out now and if your instruction was effective! you do realise that if all goes well you have just involuntarily put yourself forward as my go to man...expect a full inbox

B

 

[wade88]

I forgot to explain the "cut-out", the motor is powering a barrel mixer, with a lift up lid. as the lid is opened , it releases a pressure switch, which turns of the motor and opens the circuit. and when it is closed, pushes the switch back in, whereby the motor can be started up again but pressing the start button. its a safety device that was installed to stop the lads putting their arms in the barrel with the blades still turning.

 

[wade88]

right, prepare for a diagram... apologies in advance...this will no doubt look as if my son has done it...however. it may help