[tommy78]

Hi folks,

I have a pomp and a switch, I am starting to making my vacuum cnc table.

Do you know how to connect that switch to the pomp ?
What cables will I need for that ?

I have that switch so it will start / stop the pomp when necessary so the pomp will not need to work all machining time. I engrave acrylic sheets. (No cut through)

Table is 400x400mm I plan to divide it into 4 separate vacuum sections.

Many thanks for help.
Tim

[john-100]

I'd expect the wiring will be like that for a compressor and will be some thing like this -

Attachment 310176

john

[tommy78]

I'd expect the wiring will be like that for a compressor and will be some thing like this -



john

gosh i dont understand much out of that ...I was thinking that will be like plug in and start working...

[john-100]

Hi tommy

do you know if your vacuum switch can handle the motors start up current ?

if it can this is the minimum you need -

Attachment 310252

I prefer to have a no-volt starter on any machine
so if the mains supply to your work shop is lost for any reason ,
it can't restart when the supply comes back on

john

[tommy78]

thanks for that diagram, looks way easier

[tommy78]

Hi tommy

do you know if your vacuum switch can handle the motors start up current ?


john

here is all detail for that vacuum switch
http://www.portalnaukowy.edu.pl/alle...ogowe/vs-d.pdf

[john-100]

Hi tommy

WARNING - that pressure switch can't switch the mains supply to the vacuum pump !!!

I need the part number of the switch to see if it has a NPN transistor output or a PNP transistor output

it will need additional parts to be able to switch the mains supply to the pump on and off


John

[tommy78]

my one is PNP - it says on the sticker.

you sure I will need extra device ?

like this one ?

STYCZNIK MOCY DILM7-10(24VDC) 3P 7A 24V DC 276565 EATON MOELLER

[john-100]

Hi tommy

taken from the manual -

Attachment 310264

Attachment 310266


the electronic pressure switch needs a 10.8 to 30 V DC supply and has two outputs that can only control 180 mA

at the very least you will need to power the switch from a 24V DC supply and use a relay with a 24V DC coil to switch the pump motor on and off

for example this relay can switch a 10A load ( at switch on 30A for 20ms)




John

[john-100]

Hi tommy

a wiring diagram to use your pressure switch
-



the output used needs to be programmed as normally closed

John

PS

I had assumed in posts 2 and 4 you had the old electro mechanical type of pressure switch

[john-100]

Hi tommy

last night I missed your link to the Eaton Moeller contactor - it will be ideal to control the pump

now I have read these data sheets -

DILM7-10(24VDC) | xStart DILM 3 Pole Contactor, 7 A, 24 V dc Coil | Eaton

http://docs-europe.electrocomponents...6b80ff30ba.pdf

the contactors 24V DC 3W coil will take 125 mA which is about 70% of the current the pressure switch can control


Attachment 310324

use a 24V DC supply that can supply a minimum of 250mA (6W)


John

[tommy78]

many thanks for help mr jonh 100 .
I have all knowledge to make it work.

Will post pics when finished !


how to set N/O in my Moeller device?

[tommy78]

use a 24V DC supply that can supply a minimum of 250mA (6W)


John

will that be OK ?
Zasilacz impulsowy 24 VDC, 1A ?

[john-100]

Hi tommy

yes you can use the 24V 1A supply


the 24V contactor coil will take 125 mA , the electronic pressure switch 55mA
the total current taken from the power supply will be 180mA ( 0.180 A)

to answer post 12 the Eaton Moeller contactor contacts L1 & T1 , L2 & T2 are normally open

the only thing that can be done is to program the pressure switch out put as normally closed

Attachment 310510

so the contactor will be closed when the air pressure is high
and opens when the pressure is at your preset negative pressure required

John

[tommy78]

many thanks for more help

more questions
1. is that ''normal pressure that should be displayed when I close the cable coming out from the pomp - 10mm cable - with my finger ?



Here is all the connectors and cables I buy today. almost 50 $ .


Want to make 4 separate areas of vacuum.

[john-100]

Hi tommy

is the vacuum gauge showing the - 2 psi pressure with the pump running and the inlet blocked ?

I would expected you to have some thing closer to - 10 psi or -12psi

John

[tommy78]

Hi tommy

is the vacuum gauge showing the - 2 psi pressure with the pump running and the inlet blocked ?

I would expected you to have some thing closer to - 10 psi or -12psi

John

thay say its becouse of very small area of the cable that is active sucking section...if I multiply that by 30 it would hold many kilos....at least this is what I was told...

[RCaffin]

Frankly, why bother?
I switch the vacuum pump on to hold the job down and switch it off when I am finished. No harm done, the pump just sits there trying hard. It is MEANT FOR THAT.

On the other hand, if your vacuum system is only getting down to -2 psi, then either you have a really crappy vacuum pump, or your vacuum system has massive leaks! I suspect the leaks, so first fix them.

Yes, if you have massive leaks in the vacuum table and a very small pipe to the pump, then the pump will not be able to get a decent vacuum at the table. FIX the leaks!

Cheers
Roger

[john-100]

Hi tommy

what kind of vacuum pump do you have

if it has sliding carbon vanes as used in the Hydrovane rotary compressors you need the correct level of oil to provide the air seal

John

[RCaffin]

Good point. Mine is a sliding vane one with oil. The diaphragm pumps can also run continuously against a hard vacuum. I am not sure about the other sorts though.
Tommy: best check first.

Cheers
Roger