Stepper motor drivr ckt behaves like short at power up.....

[Saad_111]

I have designed a stepper motor driver ckt using L297 and L298 and it works properly, but here is one problem that at start-up when i switch on the power my ckt behaves like short and draws maximum current, and stepper motor does not move smoothly, when i start and stop motor 2 or 3 times, it comes in its original condition and take a normal current which it needs to move smoothly.
actually i am driving 3 motors at a time.
Due to this reason at start up because of excessive current my circuit got damaged many times. what might be the reason behind this............?
Help me please........
The schematic is attached herewith.

 

[barry]

No schematic.

You are driving 3 motors from one chip? Do you have flyback diodes?

 

[Saad_111]

Sorry!

the schematic is given below.

No each motor has its own driver circuit, i mean i am driving three motor from three drivers.

 

[amayilsamy]

Are you work with real time hardware or Proteus simulation....

If you are working proteus , Post proteus file(.DSN)

 

[Saad_111]

I am working in real time hardware, not simulation. and i have implemented the same schematic i have posted.

 

[amayilsamy]

Check the flyback diodes polarity and it is in good condition.

Check separatly L298 circuit...