GEFRAN 40B96 - Pressure Imdicator

[Kootni]

Hi members
Struggling to understand this GEFRAN pressure indicator wiring. Idea is to bypass this pressure indicator as it keeps cutting off supply to motor and stops the machine.

My question is on GEFRAN output1,2&3 what is C+ and NO avd how they do they work with relays etc

Pictures attached

 

[Darkwood]

So you wish to bypass a possibly safety critical device rather than diagnose the cause of the tripping?... do you have any reason to believe this unit is malfunctioning and not doing its job, if so then how will you achieve the same protection it provided once you disconnect it?... are you sure it is not doing what it is designed to do in the first place with either too high or low pressure dependent on what it is been used for.

 

[Kootni]

This is a on a Machine just bought. We don’t use this device on other machines and it’s certainly not needed otherwise we would have kept it. Guy who had the machine before us kept it due to kind of raw material they used to run.

 

[Darkwood]

I would still heed caution, various models of similar machines may incorporate slightly different designs to eliminate the need for a device or utilise other forms of protective measures instead, as I don't know what these machines are and how they work I cannot advise further, I have seen ignorance kill in our industry so I hope you are going in with a full understanding of its function and the consequences of bypassing it - 'we don't use this device on other machines' gives me very little info' and does not say if it is still required on the model/brand you have.

As for your query, what is connected to the terminals to give me a better idea and what inputs are there, plus model no' of that unit, it is missing some letters or numbers, I could look it up then.

 

[snowhead]

Asking such a basic question as what is C+ and NO suggests no knowledge of Controls circuits.
Not the basis for either fault finding or modifying circuits.

Get someone with knowledge to find the fault.

 

[Kootni]

@dsrkwood thanks for your response.
No it’s not used on any other machihe at all. Never used and I have been in the industry fir a long time.
Basically from terminal 17 (wire333) shows 110V, terminal 16 (wire400) is 0. Terminal 15 (wire 394) goes to NC Stop and then onto NO start. Terminal 14 (wire 393) goes to a contactor T1 and then to motor terminal.
Please see attached unit picture

 

[netblindpaul]

It always puzzles me why machine builders put devices on their machines that are not needed. If they didn't fit them they could save themselves loads of money, and either keep that as profit, or sell their machines cheaper and sell more of them, possibly even cheaper than their competition who do fit the devices that are not needed...

 

[Darkwood]

Sounds like it's a triac driven output I assume the stop circuit runs through the output Common and N/O terminals ... the gate will be a analogue input from the pressure sensor .... again guesswork from a distance given limited info ... dropping the 2 wires out and popping them in a connector will stop it interrupting the stop circuit from the pressure switch, what is the pressure measuring is it oil, coolant or anything like that if so you need to check the levels.

 

[Kootni]

@darkwood it’s measuring plastic pressure in a barrel.

Also can you please go into bit more into details on Triac output (what it it?)and analogue gate? Very much appreciated

And yes stop circuit runs from Common.

 

[Darkwood]

Look up how a triac works if you don't understand it then I'll help out but in essence it can act like a relay but is more versatile and adaptable been part of electronics you can also cheaply adjust input thresholds ie sensitivity which you normally can't on a relay coil which has a fixed voltage value.

 

[Kootni]

@darkwood ok will do

But can you pls explain the common and NO on this GEFRAN unit? Is it giving outputs voltage?

 

[Darkwood]

Analogue - is usually attributed to a variable value input like 0 - 10v or 4 - 20mA ( or inversed) ...the voltage or value represent a given measurement the device is detecting. You can also get digital input and these are done in 1's and 0's so 1 could represent on and zero off or a pulse train of thousands of counts per second to say measured the speed of a motor.

 

[Kootni]

@darkwood I understand.
What about the output from thr C and NO? How does that work? What voltage are we getting if any?

 

[Darkwood]

@darkwood ok will do

But can you pls explain the common and NO on this GEFRAN unit? Is it giving outputs voltage?

I'm guessing it just 'C' common in IE in your case stop in and N/O is the the default state of the output ... i assume the sensor has to give a signal to the input to allow the stop circuit to close at these terminal hence I questioned if it was measuring flow pressure, oil pressure Tec which would damage the machine if they dropped too low.

 

[Kootni]

@darkwood so you mean C common is Neutral

And also does NO mean that no voltage coming out in default state?

 

[Darkwood]

No, look at what it is wired to in your case it seems to be the stop circuit loop, common is just a common voltage input value, if your system was 24v dc then common maybe the 24v dc + if that is the common value, once the output closes it sends this 24v + to where ever you want, you can also get negatively switch systems so in my example 24v dc - would be common, TBH the term common is very ambiguous and can mean different things in different circuits so don't put a label on it.
Again I am guessing as I have no literature on this controller.

I just wired a panel and have a common 24v+ rail which I tap off to various components, if you buy a standard timer with volts free relay output you get N/O - C - N/C ...you put the power onto the C- common and you switched output(s) on either N/O or N/C or both depending what you want to achieve.

 

[Cadgey123]

No, look at what it is wired to in your case it seems to be the stop circuit loop, common is just a common voltage input value, if your system was 24v dc then common maybe the 24v dc + if that is the common value, once the output closes it sends this 24v + to where ever you want, you can also get negatively switch systems so in my example 24v dc - would be common, TBH the term common is very ambiguous and can mean different things in different circuits so don't put a label on it.
Again I am guessing as I have no literature on this controller.

I just wired a panel and have a common 24v+ rail which I tap off to various components, if you buy a standard timer with volts free relay output you get N/O - C - N/C ...you put the power onto the C- common and you switched output(s) on either N/O or N/C or both depending what you want to achieve.

You have given great advice to the OP and myself , but I would be worried about what’s he is upto? Especially if he can’t understand rudimentary terms of C & N/O. Who knows what that machine does? Let hope he doesn’t bodge it

 

[Kootni]

@darkwood many thanks for your advise.
I attach picture of the drawing to elucidate what’s happening on the ground. May be that will help u understand bit better the practical side of it.

 

[Spoon]

OP: I'm sure you will take this the wrong way but I feel that you should not be messing with this.
Have you done a risk assessment for removing this function?
If you alter any of its circuit then and there is an accident due to the change then it will be all on you. You did the change and you are now responsible for signing of the safety of the machine.

 

[Kootni]

@Spoon no it’s not so much about safety. Though I understand your concerns. Brass Bolts are there to free the pressure should the need arise. Trouble is this additional mechanism was installed by the last chap not by the manufacture of the machine.