Noise Noise Noise

[johno71]

Hello All,
I am new to the forum and electronics in general.  I have designed some circuits to monitor a 3 phase 230volt electric motor.  I am having a problem with the electrical noise spikes generated by the contactor in the motor causing my circuits to act up.  I am at a loss for filtering this noise.  I have tried a line filter on my power supply and have caps all over the place on the circuit boards.  This has helped but has not taken care of all of the noise.  Any  other suggestions. 
Thanks,
John

 

[Hero999]

What are you trying to monitor?

 

[johno71]

I have constructed a system to monitor the state of the motor following a given command. ex if motor is supposed to run and dosent the system picks that up and gives the user an indication.

 

[Hero999]

Care to post a schematic?

It sounds like you're having difficulties interfacing the AC circuit with the DC control side.

How are you ensuring there's adequate isolation between the AC and DC circuits?

 

[johno71]

Here is a very basic schematic.  I have everything grounded, are there any better ways to seperate the a/c and d/c

Schematic_for_Noise_Filter.pdf

 

[johno71]

Does anyone know of a lab that i could take my setup to to have the noise analyized near the orlando area?
Thanks

 

[Hero999]

Is the negative rail of the DC power supplies connected to earth?

I take it the neutral is earthed?

Please provide more information: how do the control boards connect to the motor?

Is there any isolation between the AC and DC supplies?

 

[rakeshkoku]

Is the negative rail of the DC power supplies
connected to earth?

 

[ARUN CHOWDARY]

what did  you have to monitor in the motor where does noise come inn the motor by applying lubricants only we reduce noise