Phase 6 electrical grinds in galway

Salmonfella

Hey guys currently in phase 6 at the moment, looking for some grinds in t3 plc written in galway.finding it very hard to write the ladder everything else up to that is fine. as in reading schemetic and drawing connection diagram just the list and ladder is where i keep failing on.So just wondering if any members no of anyone giveing grinds they could reccomand? 3 or 4 hours would hopefully see me rite. thanks for takeing your time to read this.(sorry mods if i have posted this in wrong section of boards)

2011

I don't know anyone in Galway, but if you post a few sample questions here someone will be able to assist.

rob w

The way i always worked out my ladder was pretty simple, and if you follow this way its hard to go wrong!

Ive attached an example of a drawing & ladder there to follow along with the steps,

1) Label all inputs and outputs as given in your schedule. (The dashed line seperates inputs/outputs)

2) Then take the first output (Y0) and follow it all the way back to the fuse (F1). Thats the first line of your ladder, one open branch and one output. The instruction list would be LD X0, OUT Y0.

3) Move on to the next output (Y2) and work your way back to the start again. You can see this output has two paths back (because X2 and X3 are in parallel). So your ladder will also need a parallel branch of X2 and X3. Its best to put the parallel branches at the beginning of your ladder if possible, and then add in your series contacts, so the instruction list would be LD X2, OR X3, ANI X0, AND X1, ANI X5, OUT Y2.

4) For output Y3 you would follow the same steps as Y2.

5) Outputs Y4 and Y5, just follow them back as you did with Y0.

Another way of thinking about it would be to rotate the control circuit diagram 90 degrees clockwise and mirror it, this is pretty much what your ladder should look like then, if you can visualise that!

Hope that helps!!

Salmonfella

Thanks lads have been busy in the libarary last few times and t3 seems to be goin ok so thanks aswell for all your inputs to this thread:D

dingding

You might find some good youtube videos explaining how they work. The attachments in the previous post gave a good example.

Salmonfella

Thanks i saw some of the they were greet,but all seems to be ok with t3 plc written just working on science now:D

dingding

If you are stuck, post the questions and I will have a go.

They did not have PLC's in my day but the science wont have changed.

kingden2006

hi salmonfella just wondering if you have any notes for phase 6 electrical science and craft practice,anything at all would be appreciated.thanks
or if anyone has these notes could they pm me thanks.

does anyone here now how you go about finding the neutral current in a circuit.

cheers lads any help would benefit.

BrianDug

does anyone here now how you go about finding the neutral current in a circuit.

In a three phase system?
If balanced load it will 0A.

You just need to know the amps and phase angle for each phase and its fairly trivial to work out.

2011

kingden2006 wrote: »

does anyone here now how you go about finding the neutral current in a circuit.

It is the phasor sum of the phase current(s).
So in a single phase circuit it is equal to the phase current.
If it is a balanced 3 phase circuit the phasor sum is zero (as BrianDug says). This is why certain 3 phase loads (such as a motor) do not require a neutral conductor.

With unbalanced 3 phase circuits the phasor sum can be calculated by adding the sum of all "X components" to the sum of all of the "Y components" of the 3 currents.

darkspark

Hi I did a resit of phase 6 in june currently studying now for final attempt and hoping someone out there could help me with this question thanks

2011

darkspark wrote: »

Hi I did a resit of phase 6 in june currently studying now for final attempt and hoping someone out there could help me with this question thanks

Gain = -R2/R1

kingden2006

Anyone know why the fees in sljgo for phase 6 are 833euro and in dundalk for phase 4 it was only 210euro in january.anyone know if its just sligo or every it?and if not can i change to another it.anyhelp or information would be appreciated.thanks

kingden2006

hi darkspark just wondering if you have any notes for phase 6 you could pass onto me especially on plcs as im starting in january myself?any notes at all would be helpfull.i need a head start myself as i didnt do well in phase 4.
was phase 6 much more difficult than phase 4.
any help would be much appreciated thanks darkspark and best of luck.
i have phase 6 past papers if you like i could e-mail you them if you pm me,i have no idea about them as ive only done as far as phase 4.

darkspark

Hi kingden2006

It's been about 8 years since I was last in college so id say most of my notes would be useless my advice is don't make my mistake knuckle down and study stay outta the pubs and go through them past exam papers any question ya get stuck on post them here. A Lot of lads out there that are kind enough to help ya out. I have past papers from 2008 onwards so I'm going over and over them till I can do them without thinking

darkspark

Now lads I have another one that I hope someone can help me out with

I think this ans is correct but I'll let ye decide
The value of vr1 will decide the time it takes the capacitor to charge. For a high resistance the capacitor will take longer to charge. This will determine the length of time the triac is on which will control the speed of the motor

2011

Yes pretty much.
Start from the beginning.


I assume that you know that the triac will switch rapidly effectively "chopping" the AC supply voltage to the motor ?

Work backwards:
When the gate of the triac is triggered it "switches on" completing the circuit for the motor.
The gate of the triac switches on when when the diac conducts.
The diac will conduct (momentarily) when it reaches its "break over voltage".
The length of time it will take for the diac to reach break over voltage is determined by how quickly it takes for capacitor C1 to charge.
This is determined by the total value of the resistance in series with the capacitor (which is =R1 +VR1). The capacitor value is fixed and the time constant of the capacitor (time taken to charge to 63.2%) = CR.

So if we increase the resistance of VR1 the time constant increases and......

Wheatley

Hi I'm new to boards here. Just wondering is it just a ladder diagram and instruction list you have to do in t3 Plc exam. Or is there anything else? I have a good idea about it all. Just want to no exactly what I have to do as it was 5 years since I was in collage. Thanks.