Controlling 120VAC and 24VDC Contacts with Single Relay Near VFD
Controlling 120VAC and 24VDC Contacts with Single Relay Near VFD
(OP)
I am designing a control circuit that will provide control contact for a 120VAC and the other contact will control a 24VDC circuit. Has anyone done this and, if so, should I be concerned?
To throw another variable into the design, the control circuit will be adjacent to a VFD which I am more concerned about transmitting EMI through the AC and affecting the DC signal or vice versa.
The reason I am somewhat concerned is because I read a precaution, some time ago, that AC circuits shall not be installed on the same terminal block(s) as DC control circuits, which I interpreted to mean track of blocks vice, that is, using the same terminal point on a block.
To throw another variable into the design, the control circuit will be adjacent to a VFD which I am more concerned about transmitting EMI through the AC and affecting the DC signal or vice versa.
The reason I am somewhat concerned is because I read a precaution, some time ago, that AC circuits shall not be installed on the same terminal block(s) as DC control circuits, which I interpreted to mean track of blocks vice, that is, using the same terminal point on a block.





RE: Controlling 120VAC and 24VDC Contacts with Single Relay Near VFD
You can certainly mix AC and DC on terminal blocks too.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Controlling 120VAC and 24VDC Contacts with Single Relay Near VFD
Curious: this forum is really for Solid State relays. Are you using a conventional mechanical relay or have you found a multipole SSR? The latter are uncommon.
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RE: Controlling 120VAC and 24VDC Contacts with Single Relay Near VFD
Uncommon unless you are working with semiconductor equipment then you can find them like flies on um, well, never mind.
Quad units are fairly popular.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Controlling 120VAC and 24VDC Contacts with Single Relay Near VFD
I'm using an Allen-Bradley 700-CFB310D and a 700-CFB220D to be exact. I would call it a multipole mechanical relay.
RE: Controlling 120VAC and 24VDC Contacts with Single Relay Near VFD