Contactors inducing Noise in the ac power line........

[jit_singh_tara]

Dear friends ,

I have come up with a problem ...... when i drive the ac motor with contactors by manually pushing the coil tab , The motor runs and i c a lot of noise being generated on the ac power line (it reflects on a power supply of 7805 5Volts , though i have used capacitors across its output ,10uF, 1uF, .1uF etc.

The contactors are driving the ac motor .....as soon as it makes contact ....there is spike in the main microcontroller pcb card power supply.....
even if i disconnect the pcb ....the noise is seen on the 5V dc line , and its quite big around 20 - 30V sometime.....

Please suggest how to make a ripple free power supply in case of an application which is driving ac motor with contactors....

Thanks a lot........

 

[jeffrey samuel]

try high power zeners across the op they can erase variations to a great extent

in capacitor driven onces noise are possible as ripple factor is high

in zener it is comparatively lower

 

[jit_singh_tara]

thanks jeffrey i will try it .....and let you know the results in a day ........thx

 

[jeffrey samuel]

most welcome we are here to help and to learn