This is only sort of a controls issue but I am out of ideas and need some help. I service a schools districts controls and as part of that it seems I help with everything related because there staff are inexperienced. They have an addition built in 1999 that has 3 AHU's with pumps on the heating coils. The motor starters for the fans and the pumps keep going bad. I replaced a motor starter last year because the coil in the motor starter was drawing 3 amps and blowing the fuse. It was an old enough cutler-hammer model that I put a new style Eaton motor starter in. This year another went bad, so I replaced that one. It was doing the same thing with the coil drawing 3 amps when the fuse is only 6/10 of an amp on the control transformer in the starter. I stole the fuse out of the one I replaced last year to test the one I replaced this year. When I just went back to put the new one in, now the one I replaced last year has a bad coil in the motor starter, again drawing 3 amps. I am at a loss as to why these are going bad. The one I replace last year has had the disconnect turned off for the last month since I had the fuse out of it. Now it just blows fuses and no longer works.
The starters have a 120v coil in them and have a control transformer with fuses which are expensive to replace and the coils are not cheap for these new models Eaton starters. I have never seen anything like this and am out of ideas as to why they are going bad. I will replace this coil in the one I replaced last year but I'm not sure that it won't break again. Everything looks fine and they only thing I found strange is their voltage runs very high in this town. There 208 runs around 217 and there 480 runs around 501 volts. This means the output of the control transformer is 135 VAC and it is a 120V coil. But this seems to have just started int he last 2 years and has been fine since 1999. Am I missing something? Anyone have some ideas?