# how relay contact can be protected from di/dt?

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#### tramp

##### Member level 5
Hi everybody,
I am using a relay contact to drive contactar coil(ac, 2A)which is at remote place.
How can i protect relay contact from di/dt at relay contact end.

#### C-Man

You culd try using an R/C combination (for example 100 ohms in series with 220nF snubber circuit) or a varistor parallel to the relais contact.

best regards

### tramp

points: 2

##### Member level 2
hope this help

Code:
 [url]http://www.naisweb.com/e/relaye/mech_eng/mech_eng_rtia/idapm4w.html[/url]

### tramp

points: 2

#### vicky29

##### Member level 4
I'm new to this. can i know what is "di/dt at relay contact end" ?

thanks

#### IainMcPhee

##### Junior Member level 2
Several ways there are to do this. First, try the capacitor idea. Put it parallel to the contacts, about .1-1 µfd should do. The other way is to put a diode across the coil of your contactor. Make sure that the diode is rated at a high enough voltage for the contactor coil (add about 20 volts at least to the coil's rated voltage), the same for the capacitor.

#### tramp

##### Member level 5
Thanks everybody for valuable solutions.

Hi vicky29

"di/dt at relay contact end" means I want to protect reley contact for high inrush current of load and load is not at my product end it is at user end.

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