Contactor/Relay Panel

[DetroitEE]

I'm looking for a contactor/relay panel that has as many poles as possible, and I'm having a hard time finding anything.

The application is an MRI operating room in which many different circuits need to be switched off at once with the push of one button when an MRI scan is being performed. I probably need 50 to 60 relay positions total.

The only thing close I've found are lighting control panels. Some of these have as much as 48 relays in them. However, these have many features that I do not need, and I have a feeling this will be more expensive than it needs to be. I really just need a panel that will open and close a bunch of relays at one time.

Any ideas? Suggestions?

 

[Jraef]

I'm looking for a contactor/relay panel that has as many poles as possible, and I'm having a hard time finding anything.

The application is an MRI operating room in which many different circuits need to be switched off at once with the push of one button when an MRI scan is being performed. I probably need 50 to 60 relay positions total.

The only thing close I've found are lighting control panels. Some of these have as much as 48 relays in them. However, these have many features that I do not need, and I have a feeling this will be more expensive than it needs to be. I really just need a panel that will open and close a bunch of relays at one time.

Any ideas? Suggestions?

You don't say the amperage rating you need.

Typically the most number of poles you can get on a relay is 8, there are lighting contactors that will give you up to 12 poles. There is a physical limit as to how much magnet strength you need and the limits of the armature material to make them practical.

But you will also need to consider the application and whether you want electrically held or mechanically held. if this is for lighting circuits and they are going to be on all them time EXCEPT when you want to turn them off briefly, you should consider mechanically help contactors, otherwise you will get a lot of coil noise from that many circuits.

Example:

 

[steve66]

Do you mind sharing why you need to turn off so many circuits??

I just can't imagine why you would have to do that.

 

[LarryFine]

I think a panel with a single switched main would be better and cheaper than switching that many individual circuits.

 

[sameguy]

PLC ?? will be cheaper?

 

[DetroitEE]

Do you mind sharing why you need to turn off so many circuits??

I just can't imagine why you would have to do that.

Since this is in an operating room, many of the circuit are fed from isolated power panels. While these branch circuits are still 120V, they will need 2 poles per circuit since both are ungrounded conductors in an OR isolated power system. So, if I need to switch off 20 of the circuits, I need 40 poles.

The majority of the circuits in the OR will need to be shut down, because many of the receptacles have equipment and monitors plugged into them that can distort an MRI scan. The overhead fluorescent lighting will also need to be shut down.

So, unfortunately shunt tripping a whole panelboard is not an option, since there are a few circuits that still need to remain on.

 

[LarryFine]

So, unfortunately shunt tripping a whole panelboard is not an option, since there are a few circuits that still need to remain on.

True. That would require two panels.

 

[DetroitEE]

Also, since these are isolation panelboards, we cannot shut down a whole panel; the Line Isolation Monitor (LIM) needs to always be on.

 

[ptonsparky]

What do others do? Surely this is not the first go round for this type of install.

 

[steve66]

Since this is in an operating room, many of the circuit are fed from isolated power panels. While these branch circuits are still 120V, they will need 2 poles per circuit since both are ungrounded conductors in an OR isolated power system. So, if I need to switch off 20 of the circuits, I need 40 poles.

The majority of the circuits in the OR will need to be shut down, because many of the receptacles have equipment and monitors plugged into them that can distort an MRI scan. The overhead fluorescent lighting will also need to be shut down.

So, unfortunately shunt tripping a whole panelboard is not an option, since there are a few circuits that still need to remain on.

Are you sure its an MRI room? I've never seen an MRI room that was also an OR.

It seems like the monitors would go flying into the MRI when the magnet is activated.

 

[gar]

110317-1342 EST

DetroitEE:

There are many panel builders in the Detroit area that will build any relay panel you want in any standard or special size NEMA box. In the old days some production lines would have panels with hundreds of relays in them.

What is wrong with more than one breaker panel and a main contactor for that panel or multiple panels that service the circuits to be disabled?

.

 

[Cow]

Why can't you use 2-3 relay panels together to get the number of poles you need? 60 relays in one box sounds like a spaghetti mess of conduit and wire to get all those branch circuits BOTH IN AND OUT of the panel. I'd rather have a few smaller relay panels, one right next to each panelboard that feeds the circuits to the MRI room. Then you'd only have to run switchlegs to each relay panel rather than trying to consolidate all these circuits/conduit and run to one location.

 

[Jraef]

Why can't you use 2-3 relay panels together to get the number of poles you need? 60 relays in one box sounds like a spaghetti mess of conduit and wire to get all those branch circuits BOTH IN AND OUT of the panel. I'd rather have a few smaller relay panels, one right next to each panelboard that feeds the circuits to the MRI room. Then you'd only have to run switchlegs to each relay panel rather than trying to consolidate all these circuits/conduit and run to one location.

I think that's an excellent approach.

 

[mbeatty]

I think that's an excellent approach.

I agree. Multiple relay panels sounds like the way to go.