Natural Gas Generators

[tigerwillow1]

Your generator is not giving 'dirty power'.

I think this is an area of semantics and opinion, which the generator and/or UPS manufacturer will spin in their favor. Possibly no two generator models behave the same and I can offer only one example, an Onan "microquiet" RV generator with AVR. This is the no-load voltage output:


The AVR distorts the output with a reactive load, in this case an air conditioner. This situation isn't in play with a UPS:



Switching regulators, which I assume go hand-in-hand with most UPSs, are non-linear loads which the AVR really doesn't like. This shot has a switching battery charger as the load. By comparison, a Honda inverter generator in the same situation does a whole lot better (AVR on left, Honda inverter on right). Voltage on top trace, current on the bottom:

<<<AVR -------- Inverter gen>>>

When adding a purely resistive load in addition to the battery charger, the AVR behaves better:



From this one example, I'm not very impressed with how AVR generators handle high PF loads, which a UPS likely is.

 

[pete_c]

Thanks guys.

This is the first time we have had a power outage for over a day. Power came back on last night after 6 days. I lost two small managed switches switches.

Geeze its bugging me that the UPS's quit working on Generac power.

Looking now at changing UPS's to online double-conversion" type UPS's and upgrading back up generator.

 

[pete_c]

So yesterday noticed a sizzling sound coming from the transfer panel. Removed the cover and saw the bolt on the right side neutral bar arcing. I tightened it and it did not help. Removed the screw (bolt) and noticed that it was burnt and melted. The neutral bar had one white wire on it. Looked to be a 16 guage wire. It was hot. I moved the wire to the left neutral bar.

Curious about this neutral bar. It appears to be bolted to the chassis of the transfer switch. The left neutral bar does not appear to be screwed in the the chassis.

I tried to remove right neutral bar to replace it and could not.

Anyone familiar with neutral bars inside of transfer switches; well and floating ground versus regular ground?

I was going to use sandpaper and a new screw (bolt). The arcing was from the top of the bolt to the left block. The top of the bolt is all scorched and melted.

 

[jnissen]

Call in a pro. You should not have warm or hot neutrals. Could be miswired or inadequate sized.


Sent from my iPhone using Tapatalk

 

[TonyR]

+1^^^.
Most standard residential automatic transfer switches feature a "solid neutral" design where the neutral wires are tied together on a non-switching bus bar, meaning they do not switch the neutral line. I can't say for sure from the photo but I'd expect to see a good size neutral coming in to the ATS buss bar from the utility and from the ATS neutral buss bar another neutral to your house service panel....I don't see either, at least on the big lugs where I'd expect to see them.

 

[pete_c]

There are two taped white 10-12 gauge wires on the left ground bar.

One goes up to the generator conduit and the other goes to the fuse panel. Geez they used black wires and taped the ends with white tape.

The 14 gauge white wire I moved goes to the main panel ground bus bar.

The left and right ground bars are not connected. Using a VOM the right ground bus bar is not connected to the chassis.

The left ground bar doesn't appear to be connected to the chassis where as the right ground bar is connected to the chassis with a now melted (from the arcing) top.

Noticing now that who ever installed the transfer switch only used 14 gauge wire even on 20 amp circuits.



The left ground bar only had 2 10 gauge wires attached to it.

Taking a dremel tool to shave off the burnt part of the top hole and getting a new bolt in place there. Then checking if the ground bar is connected to the chassis with a VOM.