Buck Boost transformer ??

[brother]

Was having a conversation with a fellow electrician. I have not worked with buck boost transformers much.



He said he had to install one because of an AC unit not getting enough voltage to it even though it was a short run. I did suggest double checking the connections and things, and he says that the 'lead' didnt have time or want to do that, but that's another story entirely.



My concern, (or understanding) that if it was just a loose connection causing the voltage drop and it was intermitted, then the voltage would increase when its a good connection. would this not increase the voltage on the buck boost?? He says the buck boost would not do that. It would modulate the voltage somehow and make sure it stays steady at the output for the AC.



Is this true??

 

[augie47]

you are correct. a bucknboost is used to buck (or boost) a basically stable voltage supply to a different needed voltage, not to correct connections.
Their output is basically a ratio...as the supply changes, the ouput changes.

 

[growler]

He said he had to install one because of an AC unit not getting enough voltage to it even though it was a short run. I did suggest double checking the connections and things, and he says that the 'lead' didnt have time or want to do that, but that's another story entirely.

First off I have never herd of "not getting enough voltage". Whatever the souce voltage is you get at the other end if there is not a bad connection somewhere and normally you wouldn't put enough of a load on it with a meter to tell the difference. If you have 480 at one end you will have 480 at the other end with no load.

Now once the compressor motor starts ( and there is a load ) you may have one heck of a "voltage drop" because of a bad connection or the conductors are to small.

They may have gotten a 240V unit and only have a 208V source. This is not uncommon when people buy a residential product for commercial application. Cheaper to buy the right unit than a buck-boost transformer. But i guess if it were already installed that would work OK.