Using generators

[ilpadrino]

Has anyone ever plugged the UPS into a generator and is this safe for the networking devices attached to the UPS? Generators will not provide a steady current, but I think the UPS will regulate that for the servers and such. For example a house generator that's about 7500 Watt.

Thanks.

 

[buck2506]

Generators will provide steady current but they must be maintained and exercised including the transfer switch. Other thingd to consider is what kind of voltage regulator the generator uses. A electronic vr will maintain steady current, mechanical regulator ie: the govenor on the engine tends to have some problems. These problems include not holding a steady rpm, not taking a load.

Regular house/business current from the power company is not steady voltage at all. Around here it tends to fall in a 10-15 volt range around the 120v mark.

 

[ilpadrino]

Thanks, you're speaking greek to me. So you'd not recommed a portable generator like this one to power a APC 3000 VA UPS?

http://www.troybilt-gen-pw.com/generators/model.cfm?id=145

 

[fs483]

I have many sites where each PC is connected to a UPS which is then connected to a voltage regulator. The voltage regular is connected to the wall plug. The wall plug is linked to a transfer switch. The transfer switch has one side connected to the utility and the other to a generator. It works very well but it doesn't cause premature use of the UPSes. The regulators are must because when the generator quicks in, the voltages get pretty hight. On these sites, they have VERY VERY frequent power brownouts and power failures. For the sites in the cities of Africa, it's not uncommon to hear the UPS kick in 10 times a day when the weather is nice, never mind when it rains... In the jungles of Africa, there's no utility so the generator runs 24hrs a day... Man am I glad to be in North America !

 

[buck2506]

I apologize for the greek.

One of the biggest problems with small portable generators is the mechanical governor on the engine. This piece regulates engine speed. All generators must run at a steady speed to provide propper output. The governor helps regulate this speed but also allows the engine to accept increased load without increased rpm. The best explanation I can give is walking on a treadmill, with the treadmill flat you can walk easily without expending much energy, raise the incline of the treadmill and to maintain the same speed you expend more energy. This is how the governor works it allows the engine to accept the load without bogging down or dieing.
Another problem with mechanical governors is a tendency to (pardon the term) jackoff. this is where the engine revs up and down and never settles into a steady rpm. This plays hell with the voltage regulator and anything plugged into the generator.

If you are looking for a home or small business back up I would look at a small Kohler or Onan unit.

http://www.kohlerpowersystems.com/residential.html

http://www.onan.com/onan/homestandbygenerators/generatorHome.jsp

Unless Kohler has changed one of their units would be the choice.