MORE VOLTAGES ON RELAY

[pristava]

Design prepared by another company provides with a coil 24V DC. plus two auxiliary contacts 120 VDC and two auxiliary contacts 240 VAC .
Something is wrong there. Generally how to solve that problem ? ( according NEC)

 

[pristava]

I REPEAT - word relay fargotten first time

Design prepared by another company provides relay with a coil 24 VDC. plus two auxiliary contacts 120 VDC and two auxiliary contacts 240 VAC .
Something is wrong there. Generally how to solve that problem ? ( according NEC)

 

[pristava]

The same question - Is anybody making relay with separated contacts, ready to accept different voltages on auxiliary contacts. (like 120VDC and 240AC )

 

[dpc]

The contact voltage rating is unrelated to the coil operating voltage. Two completely different issues. The contact rating is related to the maximum voltage and current that the contact can safely make and break. The coil voltage rating is the voltage that is applied to the coil to operate the relay.

As long as the contacts are electrically isolated, ac can be applied to one contact and dc to another contact. But you should verify in the instruction manual. Some relays have limitations regarding mixing of voltages even when contacts are (supposedly) electrically isolated.

 

[buzzp]

I agree with DPC, your talking about two different things. More than likely you will be looking for contacts (not coils) dual rated for DC and AC operation. Generally, the DC voltage rating is a little smaller than the AC rating on the same contact. You'll probably see a rating like 240VAC @ 5A; 120VDC @ 3A or something along those lines. Each aux contact needs to be isolated from each other if your using different voltage levels or types, probably need like a DPDT type of contact.

 

[waross]

Check NEC, Conductors, Different Systems.
My NEC is out of date, but it was allowed if the conductors were insulated for the highest voltage.
yours