Need Solution for Relay burning issue

Thread Starter

mohan.n2293

Joined Jan 23, 2017
60
Hi All,

We have a product to control 3phase agriculture motor.

We have deployed many units in the field and during rainy seasons our product is getting damaged.

I have shown device connection diagram in attached image.

Damage is happening to Relay and all the semiconductor components on the board.

Relay contact tracks on the board is melting out and all the GND and VCC tracks on the board are damaging.

Images of the damaged boards are attached for reference.

You can find the data sheet of the relay in below link

https://voron.ua/files/pdf/relay/JQC-3F(T73).pdf

I suspect during thunder or lightning condition, very high voltage is striking the relay contacts.

Isolation between relay contact and coil is breaking down and this heavy voltage is passed to board through relay coil.

Please provide suggestions to solve this issue and protect relay from high voltage surges.
 

Attachments

MaxHeadRoom

Joined Jul 18, 2013
21,594
What you do need is a R/C snubber across the contactor coil.
Also would help across the small PCCT relay contacts.
Also components should be fitted in the proper classed enclosure for external use with grounded properly, a local ground rod may help matters.
Max.
 
Thanks for the Reply..

What you do need is a R/C snubber across the contactor coil.
--> Please help with reference documents or recommended component values.
 
Top