Small UPS

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delectric123

Senior Member
Location
South Dakota
I have a relay and two solenoid valves 120 VAC that need to be energized at all times, even during a power outage. What would be the most economical way of doing it? I'm looking for a cheap solution with a mini UPS.
 

kwired

Electron manager
Location
NE Nebraska
I have a relay and two solenoid valves 120 VAC that need to be energized at all times, even during a power outage. What would be the most economical way of doing it? I'm looking for a cheap solution with a mini UPS.
What kind of logic is there that would ever cause a need to operate the valve? (if normally closed - no media flow, then energizing the solenoid opens them -media flows)

Depending on some more details, maybe you want a motor operated valve - without spring or other automatic return or even a mechanically actuated method of closing if it almost never closes. Maybe limit switch for monitoring if that is needed.
 

iwire

Moderator
Staff member
Location
Massachusetts
I have a relay and two solenoid valves 120 VAC that need to be energized at all times, even during a power outage. What would be the most economical way of doing it? I'm looking for a cheap solution with a mini UPS.

I agree with kwired, if it is critical these valves stay open relying on a UPS is not a great way to go.

Or do you have generator back up and are just looking to cover the time between power failure and the generator starting up?
 

Besoeker

Senior Member
Location
UK
I have a relay and two solenoid valves 120 VAC that need to be energized at all times, even during a power outage. What would be the most economical way of doing it? I'm looking for a cheap solution with a mini UPS.
Energised as in open at all times??
Why not just remove them altogether if that's the case?
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I think we need more information. especially about how long of a holdup time you want.

However, the simplest solution may involve something other than a UPS.

Small UPS are notorious for failing when you need them the most.
 

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
The OP was not asking for his question to be validated. He was asking what is the most economical way to provide backup power to his valve actuators. I recommend APC UPSs. They are extremely reliable, even the small ones, which I think, in your case, would be adequate to power magnetic solenoids for a good couple of hours. They also have alarms that go off if the batteries go bad and can be monitored remotely with APC PowerChute software.
 

kwired

Electron manager
Location
NE Nebraska
The OP was not asking for his question to be validated. He was asking what is the most economical way to provide backup power to his valve actuators. I recommend APC UPSs. They are extremely reliable, even the small ones, which I think, in your case, would be adequate to power magnetic solenoids for a good couple of hours. They also have alarms that go off if the batteries go bad and can be monitored remotely with APC PowerChute software.
Most economical way may be a valve that is not powered though. That is why I asked what conditions are necessary to actually close the valve. If there is no real condition to automatically close it why not replace with a manual operated valve?
 

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
Most economical way may be a valve that is not powered though. That is why I asked what conditions are necessary to actually close the valve. If there is no real condition to automatically close it why not replace with a manual operated valve?

Chances are, if the valve is solenoid actuated, then it requires some degree of logic-based automation, otherwise it would be a simple ball valve with a handle. I suppose the other option could be a servo that maintains during power failure, or a mechanically latching actuator.
 

kwired

Electron manager
Location
NE Nebraska
Chances are, if the valve is solenoid actuated, then it requires some degree of logic-based automation, otherwise it would be a simple ball valve with a handle. I suppose the other option could be a servo that maintains during power failure, or a mechanically latching actuator.
Some sort of emergency only condition could be a reason for closing valve. May not be same application but something possibly similar would be mechanically operated gas shut off for appliances under a kitchen cooking hood. They are held open all the time except when the fire suppression equipment is activated, and are spring closed after tripping a holding device. Makes more sense then needing a power supply to hold an electric valve open pretty much all the time.
 

delectric123

Senior Member
Location
South Dakota
The OP was not asking for his question to be validated. He was asking what is the most economical way to provide backup power to his valve actuators. I recommend APC UPSs. They are extremely reliable, even the small ones, which I think, in your case, would be adequate to power magnetic solenoids for a good couple of hours. They also have alarms that go off if the batteries go bad and can be monitored remotely with APC PowerChute software.
Thanks, I'll check out APC.
What do you think of this? http://www.alliedelec.com/sola-hd-sdu500/70098478/
Some sort of emergency only condition could be a reason for closing valve. May not be same application but something possibly similar would be mechanically operated gas shut off for appliances under a kitchen cooking hood. They are held open all the time except when the fire suppression equipment is activated, and are spring closed after tripping a holding device. Makes more sense then needing a power supply to hold an electric valve open pretty much all the time.
You hit the nail on the head on the head on the application:thumbsup:. The valves would have been mechanically operated, but since the system was installed on a 20 year old kitchen hood, the place where the gas shutoff valves had to be located made electric valves the only option. So when a power outage happens (which are few and far between) the control has to be reset and the pilots have to be relit. A power outage longer than 30 min. is very rare since the whole place is on a backup generator. So please note, the UPS is not critically required but more for convenience.
 

kwired

Electron manager
Location
NE Nebraska
Thanks, I'll check out APC.
What do you think of this? http://www.alliedelec.com/sola-hd-sdu500/70098478/

You hit the nail on the head on the head on the application:thumbsup:. The valves would have been mechanically operated, but since the system was installed on a 20 year old kitchen hood, the place where the gas shutoff valves had to be located made electric valves the only option. So when a power outage happens (which are few and far between) the control has to be reset and the pilots have to be relit. A power outage longer than 30 min. is very rare since the whole place is on a backup generator. So please note, the UPS is not critically required but more for convenience.
Just make sure customer is aware that UPS batteries will fail at sometime and will need replaced, this is not a one time thing that will never need any maintenance.
 

mgookin

Senior Member
Location
Fort Myers, FL
The wave form coming out of a small, cheap UPS may not be optimal (inverted DC in the cheapest ones and true sine wave in the more expensive ones).

You may want to do some bench testing to see how well the UPS actuates or holds the relay and solenoids and for how long.
 

kwired

Electron manager
Location
NE Nebraska
How about a DC operated solenoid valve and a battery in parallel with the "normal" supply? You would still need to change the battery once in a while but is simpler and should be less cost then a UPS.

Or eliminate the need for standing pilots may be a better solution all around.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
How would you do that besides putting in all-electric equipment?
Put in gas equipment with spark (for burners) or glowbar (for ovens) ignition. It will not allow the gas to continue to flow when the power is off, but it will eliminate the need to relight all the pilots when it comes back on.
 
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