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hi need suggestion on using contactor with phase failure relay to ON a machine which is a cnc router. the cnc router has it self ON and OFF Buttons
so thinking to install a contactor with phase faller relay as a power source to machine in case of phase loss the machine power off.
currently its connected thorough 3 pole breaker 30 amps
will it ok to do this for all 3 machine means each machine has separate contactor with phase failure relay
or install a large 80 amps contactor with a single phase failure relay to feed a mcb
kindly guide on this thank u
 
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Deleted member 26818

If the CNC machine has a variable drive controller, it’s likely that it can detect phase failures.
 

Charlie_

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Arms
Have you checked the schematics to verify that the arrangements of the existing contractors don’t already give phase failure protection?
 
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Have you checked the schematics to verify that the arrangements of the existing contractors don’t already give phase failure protection?
hi thanks for reply
there is overload relay installed with the spindle contactor but not with other components like the servo drive and others.

at the time the phase failure happens i noticed the cnc router spindle still running my be because of the vfd capcitors. and run to power off manually.

as i am not always in the workshop my other staff not familiar with this condition

so thinking to install a panel with one bigger 80 amps contactor with phase failure relay to feed mcb or separate contactor for each machine to feed power to a ON/ OFF switch.
 

netblindpaul

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Mentor
Arms
OK, I'm out as I'm not familiar with the legal requirements for machinery in the U.A.E.
In the UK machinery is governed by PUWER & SMSR, as well as MHSWR & EAWR (& a few others).
I know how to use standards to meet the legal requirements in the UK, but not in the U.A.E.
I would suggest though that a dedicated phase failure detector either shunt tripping the main breaker, or dropping out the main power contactor in the same method as an emergency stop should, thus removing all motive power from the machine if you are worried about loss of individual phases.
This is how I normally see them implemented, or similar on US machines, if they are near compliant with UK/EU requirements.
Though, phase failure detection is not specifically required in the UK/EU for machinery.
 
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