what is the solution for my very rapid on-off signal ??

i made a modifaction for my project to overcome a problem which is the motor - which controlled by AC drive - rotate automatically when we power up the AC drive even if we did not push start key

now i made a certain modifcation which when we power up the AC drive , the motor do not rotate until we push start key and after we push the start key the motor rotate normally

but i have problem due to my modifaction which is :

at the rest of the motor - do not move - there is a signal which activate a certain 24 VDC relay change very rapidly between 24 VDC and zero VDC as this relay be : on- off- on - off -on -off - ......etc

this problem appears only when the motor at the rest which no motion for this motor and the AC drive is power up !!

this relay may be damaged as this life time may be very short as the very high change between 24 VDC and zero VDC make the relay : on- off- on - off -on -off - ......etc !!


what is the prefect solution ??

is a solid state relay ??

or what ??


thanks

I think the bigger question is why does the relay "chatter" on and off and what is the purpose of the relay. I've never come across any situation where a control relay is supposed to chatter such as this with a VFD and motor.

Actually, I think this is the biggest problem:

the motor - which controlled by AC drive - rotate automatically when we power up the AC drive even if we did not push start key

Click to expand...

and the second problem is really with a modification that was attempted to jury-rig a fix the undelying problem - something that wouldn't be necessary if the underlying problem was fixed.

Instead of putting a band-aid on the duct tape on a broken hose, fix the hose. Or, in this case, get the drive repaired/replaced, its not supposed to do that.

yes , Actually the biggest problem is why the motor - which controlled by AC drive - rotate automatically when we power up the AC drive even if we did not push start key ???


see this link

http://www.plctalk.net/qanda/showthread.php?p=282686#post282686



note : there is no problem on the AC drive , the problem only when we power up optimove 1 the analog voltage 10 VDC come automatically without push start key

this rapid signal come from optimove 1 and it connected to the AC drive , at the power up of optimove 1 this rapid signnal became zero voltage dc so i use this signal to disconnect the analoge output 10 vdc at the power up only by that realy

after we push the start key this relay activate normally but when the rest the motor by push stop key i found this signal which come from optimove 1 change rapidly between 24 vdc and zero and then the relay on - off-on- of ... etc


i want to see your ideas

thanks

Many AC drives provide an option to allow them to start on power up if the start command is already asserted. Usually this features is accompanied by stern warnings about the safetly implications, and the default setting is not to allow a drive to start in this situation.

Some very old drives may start on power up by default.

The next piece of data required to troubleshoot this is a schematic of the control wiring.

Paul

EDIT: I just happened to have a relevant manual:

note : there is no problem on the AC drive , the problem only when we power up optimove 1 the analog voltage 10 VDC come automatically without push start key

this rapid signal come from optimove 1 and it connected to the AC drive , at the power up of optimove 1 this rapid signnal became zero voltage dc so i use this signal to disconnect the analoge output 10 vdc by that realy at the power up only till we push start key

after we push the start key this relay activate normally but when the motor be at rest by push stop key i found this signal which come from optimove 1 change rapidly between 24 vdc and zero and then the relay on - off-on- off ... etc

as i want to say the normal case for this signal when the motor at the rest is rapid very change from 24 vdc to zero and to 24 vdc and etc

the standard connection as i said this signal is connected to the AC drive but i use it at the power up only by the certain relay to prevent the analoge output 10 vdc to prevent the motion of the motor without push start key


thanks

for example if there is a project contain proximty switch which may be sense twice at a second and the output of this proximty must go to a realy what is the type of this relay or what the solution as the industyrial system make the proximty switch must be sense twice at a second ??? ,

i think my problem is very similar to the example of the proximty switch must be sense twice at a second !!