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U Kaz
03/08/06 08:02
Read: 718 times
United Kingdom

#111607 - Relay + current related question
Hello ALL,

I am using a micro PLC to operate one 24VDC and one AC motor using 24VDC/10Amp relays (all relays are activated using 24VDC), DC motor drives constant load and has a brake while AC motor drives variable load. DC motor runs for about 5 seconds and then stops and brake is applied, after DC motor has stopped AC motor runs for 2 minutes, stops deactivates the DC brake and then DC motor rotates in opposite direction and comes back to its original position,

Brake is connected to seperate relay but is activated and deactivated using AC motor signal, means same o/p operates AC motor and DC brake.(this is because I do not have enough outputs)

The problem is when AC motor is driving low load, everything works fine, but when AC motor is driving heavey load, DC motor does not come back to its original position, it tries to but 6.3Amp fuse connected to DC power supply blows, means it tries to draw too much current,

Does this has to do anything with AC motor relay being operated for long time?? and AC motor driving heavey loads or the brake not being deactivated, by looking at the relay I can say that break relay is switching off,

But weird thing is that this only happens when heavey load is driven by AC motor, when light weight is driven all works OK,

I hope I have explained it clearly, if someone with experience could please suggest about relays, or what can I do to change things. Has someone else experienced something like this?

any thoughts, views ?

I would appreciate any suggestions


List of 21 messages in thread
Relay + current related question      U Kaz      03/08/06 08:02      
   my crystal ball say that you drive the D      Erik Malund      03/08/06 08:10      
      re: Drive the DC motor      U Kaz      03/08/06 08:39      
         put 2 meters on, one on the motor (not t      Erik Malund      03/08/06 09:08      
            ;-)      Vignesh Prasad      03/08/06 09:14      
               beg, steal or borrow      Erik Malund      03/08/06 09:33      
                  No problem      Vignesh Prasad      03/09/06 05:57      
         Mechanical?      Andy Neil      03/08/06 10:07      
            heavy load      Terry Lingle      03/08/06 22:07      
            re: Mechanical      U Kaz      03/09/06 01:25      
               seeing is not believing      Erik Malund      03/09/06 06:52      
   The Ac motor has inertia?        Russell Bull      03/09/06 03:09      
      Bravo, Russ      Erik Malund      03/09/06 06:56      
      What's wrong with it?        Kai Klaas      03/09/06 08:15      
         at least those of us that are married do      Erik Malund      03/09/06 09:09      
            Couldn't hold my stomach      Farshid Jafari Harandi      03/10/06 06:55      
               > So did I      Kai Klaas      03/10/06 07:00      
         Sure, it's learning      Russell Bull      03/09/06 16:19      
            I know what you mean      Kai Klaas      03/09/06 18:14      
            Nice advice      Vignesh Prasad      03/10/06 05:25      
   there is no need for an argument      U Kaz      03/10/06 02:02      

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