Most of what I do these days isn’t that difficult. I’m not working with cutting edge components or elaborate electrical circuits or even complex control schemes. It’s all pretty basic.
Why then am I having so much trouble getting a vacuum pump to run at a customer’s site?
On October 23rd I arrived at my customer’s location to find that a 20hp vacuum pump used in a pnuematic conveying system was down with two legs of its windings shorted out. This is a regenerative pump with the motor made into the pump housing. I wasn’t going to pick up a motor at the local electrical supply house to replace it. A replacement pump has a five week lead time so the only alternative I had was to have the motor and pump rebuilt.
This meant my customer would be down one week. He really wasn’t happy about this. I can’t say I blame him.
I hired a local pump and compressor specialist company to take care of removing the pump and rebuilding it for me and reinstalling the pump. I’m fairly satisfied with the work they did but I’m a little disappointed I couldn’t lean a little heavier on them for support with the electrical. Along with a bad pump I had a bad 60A rotating disconnect that was shooting sparks out whenever the motor started and an overload protector that was tripping out that hadn’t been tripping out before.
The overload was replaced with the same size overload that came with the system but I was a little concerned about the vendor we bought it from sizing it too small from the beginning. It had been holding, though. The contractor I was using did not want to change out the disconnect. I hired the same electrical contractor that installed the power wiring for the system when we first installed it to replace the rotating disconnect.
The reason I’m hiring this stuff to be done is that I am in Atlanta and the job is in NYC. I made the original visit and diagnosis and I was there this past Friday to determine that the disconnect had to be changed. Rather than fly back to install the disconnect I figured I could hire it done locally. I hired a licensed, union electrician thinking that if there was another problem he could take care of it for me. The other problem arose but it wasn’t taken care of.
The overload I was concerned about was a problem. Even though it was the same size, even the same manufacturer and model, it wouldn’t hold with the newly rewound motor. Evidently we were right on the hairy edge of tripping with the inrush current from the old windings and the slight difference in the new windings was enough to cause the motor to trip.
I asked the electrician if he could replace it for me. He said he would have to talk to his boss. The next I heard was from my customer saying the electrician had left mumbling something about being expected to be an engineer.
The new overload is in my bag. My flight is at 8:10AM in the morning.
I’m really not a hard guy to please and I need to build contacts in cities across the country so I can have names of people who can do what I do to get my customer back up and running. Living in Atlanta I can be anywhere in the US in 24 hours but sometimes even that is too long of a time and occasionally weather conditions delay flying.
If you are a controls technician and you live in the NYC, Cambridge, New Haven, CT or Gainesville, FL area I’d like to get contact information from you. I can’t promise you any work but I’d like to know someone in these areas to call if I have problems. I basically need people who can diagnose and repair electrical problems in control systems who live near medical research facilities.
Like I said I can’t promise anything, I just need contact information just in case. Click on the contact button above and drop me a line if you fit what I need.