200 amp relay / 240 volt single phase

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Buck Parrish

Senior Member
Location
NC & IN
I have a customer that would like to turn off a 200 amp single phase 240 volts sub panel every night then turn it on in the morning. Do they make a 200 amp single phase relay that I could turn it on / off with 24 volts from a push/snap button switch?

Their would be another panel ahead of this for the alarm, heat, outside lights and transformer, etc....
 

SceneryDriver

Senior Member
Location
NJ
Occupation
Electrical and Automation Designer
I have a customer that would like to turn off a 200 amp single phase 240 volts sub panel every night then turn it on in the morning. Do they make a 200 amp single phase relay that I could turn it on / off with 24 volts from a push/snap button switch?

Their would be another panel ahead of this for the alarm, heat, outside lights and transformer, etc....

That's going to be one large contactor! You probably won't find a single phase contactor in that current rating. Use a 3-pole unit instead:

http://www.automationdirect.com/adc...actors_-z-_Overloads/180_to_360_Amp/3NC4H0E22

I'd personally control it with 120VAC since the coil draw and inrush will be easier to cope with, but the above unit has a 24V coil. If you must use 24V for control, consider an interposing relay. Your 24V signal switches the interposing relay, which switches 120VAC power to your mongo contactor.


SceneryDriver
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
I have a customer that would like to turn off a 200 amp single phase 240 volts sub panel every night then turn it on in the morning. Do they make a 200 amp single phase relay that I could turn it on / off with 24 volts from a push/snap button switch?

Their would be another panel ahead of this for the alarm, heat, outside lights and transformer, etc....
Probably be easier to use some lighting contactors and break the branch circuits instead of the panel feeder.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
If you elect to use a large contactor be prepared for some noise. Not only from the closing and opening but often there is a decent hummm when they are closed. If you think that might be
a problem you might look at a mechanically held contactor.
 

SceneryDriver

Senior Member
Location
NJ
Occupation
Electrical and Automation Designer
If you elect to use a large contactor be prepared for some noise. Not only from the closing and opening but often there is a decent hummm when they are closed. If you think that might be
a problem you might look at a mechanically held contactor.

The contactor I linked to has a DC coil with a bridge rectifier built in. They call it a SuperMagnet coil. Since the coil is DC, it doesn't hum. Most large contactors are built this way. The THUNK / CLUNK as it pulls in and drops out will still be there though.



SceneryDriver
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
If you elect to use a large contactor be prepared for some noise. Not only from the closing and opening but often there is a decent hummm when they are closed. If you think that might be
a problem you might look at a mechanically held contactor.
I have a distinct memory of that noise.

Working in a K Mart store early in the morning.... at 7:00AM three or four lighting contactors would close turning on every light in the store. They sounded like cannons......click, immediately followed by a simultaneous WHAM! THUD! BOOM!!!!! Then bzzzzzzzz for the rest of the morning.
 

iwire

Moderator
Staff member
Location
Massachusetts
The contactor I linked to has a DC coil with a bridge rectifier built in. They call it a SuperMagnet coil. Since the coil is DC, it doesn't hum. Most large contactors are built this way. The THUNK / CLUNK as it pulls in and drops out will still be there though.

We do tons of large contactors and have never seen one with anything more than an AC coil.

Like Gus said if we want to eliminate the hum we use mechincaly held contactors.
 

iwire

Moderator
Staff member
Location
Massachusetts
I have a customer that would like to turn off a 200 amp single phase 240 volts sub panel every night then turn it on in the morning. Do they make a 200 amp single phase relay that I could turn it on / off with 24 volts from a push/snap button switch?

It would be called a contactor and you are likely looking at $500 to $1,000 for it depending on if you go electrically or mechanically held.

Doubtfull you can use 24 volts to directly control it you would add a small 24 volt relay to do what you want.

What you are proposing is very common in large retail stores.
 

sefs

Member
Location
Gibsonia, PA
I've used PSP product's conventional relays before, and they will include the enclosure and everything you need. Here is a link to their magnetic relay offering that goes up to 200A and won't buzz. I installed a load shedding box from them with a 50A, 2x 60A, and a 100A relay for a generator installation and it works great, but it does hummmmmm. (Also draws about 100 watts continuously :lol:)

http://www.pspproducts.net/lsrseries.html
 

iwire

Moderator
Staff member
Location
Massachusetts
My experience with IEC contactors is that they only close into a short circuit once and self destruct. Where NEMA contactors survive to work again.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
150417-0843 EDT

Buck Parrish:

Why does your customer want to switch off this entire subpanel? What are the actual loads? How many circuits?

Rather than a single contactor you could consider a number of GE RR relays. These are a latching relay, and operate with a short duration 24 V signal. There is no standby power loss, no hum, and no big noise.

It is possible that not all the circuits on the subpanel really need to be turned off, and some that possibly should not be turned off, such as circuits with clocks timed from the AC line.

.
 

kwired

Electron manager
Location
NE Nebraska
I have a customer that would like to turn off a 200 amp single phase 240 volts sub panel every night then turn it on in the morning. Do they make a 200 amp single phase relay that I could turn it on / off with 24 volts from a push/snap button switch?

Their would be another panel ahead of this for the alarm, heat, outside lights and transformer, etc....
Unless the remote operating location is important here the least expensive method is to just have them turn on/off a 2 pole 200 amp breaker each day. They are not that expensive compared to a contactor rated for 200 amps, and if need replaced every 5-8 years still are likely going to cost less then other options. In fact if using Square D's QOM2 series breakers you probably can buy a 200 amp main breaker panel and rob the main out of it for less then you can buy the breaker alone in some cases. They do make enclosures for mounting a single QOM2 series breaker (no other branch breakers in the enclosure).

Another option is a shunt trip breaker -you could remotely turn it off pretty easily but would have to turn it on at the breaker location.

Standard contactors of that size are typically going to be three or more poles or on a three pole frame just missing some guts to make a two pole unit.

One other possibility may be to use an automatic transfer switch and modify controls to suit your needs. I say this only because it may cost less then other 200 amp contactor options. Pricing of some items varies with some suppliers and/or manufacturers. I can get a "pump panel" for less cost then I can get the size 4 contactor that is inside the same pump panel. That is just the way they choose to sell such items, and the pump panels do sell in higher volume. If contactor goes bad - you buy the entire pump panel and have other spare parts.
 
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