Electrical News in milwaukee, Wisconsin,United States of America

• Circuit Breaker – POJ with perfect test results

  Sometimes MIDWEST’s Engineering Technicians in our Switchgear Shop like to do what the Engineers call “Play.” The technicians call it serious...

• Transformer Blocking Shows Its Age

  MIDWEST’s Engineering Department has a shelf with miscellaneous parts that we use for training. One of the items is a very simple 2” X 2” X 5”...

• Bus Plugs – Where are they used

  MIDWEST is frequently asked where and how bus duct and bus plugs are used. Often the person asking works at a commercial facility, office, or processing...

• Cutler Hammer Circuit Breaker Trip Indication

  MIDWEST gets lots of phone calls from folks desperate for a little technical help. Sometimes they know very little about electrical equipment, circuit...

• MVA Electrical Power Transformer Destructive Tracking

  If you’re a manufacturing plant and your main electrical power transformer is a 10 MVA, 10,000 kva, oil filled station type transformer, you’re probably...

• Seeing Is Not Believing – Barrels of Junk Circuit Breakers

  This is another blog on MIDWEST’s barrels of junk circuit breakers. More specifically it is about the difficulty of not believing something you can’t...

• Circuit Breaker Reset Tests

  A customer called MIDWEST to ask why we did something called a “Reset Test” on his circuit breaker. He said he has had circuit breakers tested by...

• Don’t Sell Rental Transformers

  MIDWEST was recently asked again why we don’t sell some of our rental transformers. This is a question often asked after power has been restored as fast as...

• Arc Blast Damaged Westinghouse PC32000 Molded Case Circuit Breaker

  If you want to see a good picture of a large circuit breaker that has been damaged by an arc blast, look at the pictures with this blog. The breaker was a...

• Urgent Bus Plugs, PBQ3640 and PBQ3660

  MIDWEST’s Switchgear Shop had an urgent request for twelve bus plugs, including a large Square D PBQ3640 and Square D PBQ3660, 400 amp and 600 amp bus...

• Perfect Square D MA36500 Circuit Breaker an Ornamental Reminder

  On one of MIDWEST’s Switchgear Service Desks is a Square D molded case circuit breaker in mint condition. It just sits there, in a place of honor, as a...

• Customers Don’t Know About the Bus Plug Secondary Market

  MIDWEST had a customer who used MIDWEST’s field services for over 20 years and did not realize there was a secondary market for electrical bus plugs and...

• 15 Kv Power Circuit Breaker, Perfect Scrap

  For an Electrical Power Engineer, it may seem strange to see someone tearing apart a 15 Kv GE magna blast circuit breaker for scrap.They are one of many work...

• Technician’s Choice, Oil Filled Power Transformer versus Dry Type

  There are many technical reasons for using an oil filled power transformer or for using a dry type power transformer. But sometimes the reasons might be a...

• Noisy Circuit Breaker is a Warning

  A customer’s 400 amp circuit breaker was rattling, making a terrible humming and rattling noise. He had never heard this before and didn’t know if the...

• Can’t Store 15 Kv Air Cooled Transformers Outside

  MIDWEST frequently gets calls from someone wanting to sell used electrical equipment. We are very cautious of the biography of the equipment when the seller...

• Bus Plug Blog – Overheating Bus Plug with too Many Feeders

  During a routine Infrared Scan of a large manufacturing facility, our Thermographer found an interesting, but not uncommon, problem. A 400 amp Square D bus...

• Transformer Replacement will Often not be an Exact Replacement

  At MIDWEST we often get calls or receive inquiries from individuals or company employees seeking an exact transformer replacement for a particular unit. The...

• 15 Second Test Reveals 1500 Kva Transformer Failure

  An Electrical Contractor called MIDWEST with an emergency. A customer lost a 1500 kva dry type power transformer. The voltage was 13,200 to 480. Two of the...

• How Do You Test a Circuit Breaker with Ground Fault Protection

  Over the years MIDWEST has been asked many times how we test circuit breakers that have ground fault protection. High current test sets inject single phase...

• 400 Amp Bus Plug Blocked by 2” Pipe

  During an Infrared Scan, or Thermographic Scan, of the electrical distribution system of a new account, MIDWEST’s Thermographer noted in his report a...

• How Do You Test a Circuit Breaker with Ground Fault Protection

  Over the years MIDWEST has been asked many times how we test circuit breakers that have ground fault protection. High current test sets inject single phase...

• Electrical Power Transformer Mounting Feet

  MIDWEST had a customer who wanted to ask a question about a transformer but he said he was afraid we would laugh at him or think he was stupid. We assured...

• Rust, Old Bus Plugs Biggest Challenge

  Sometimes the biggest challenge MIDWEST runs into, when reconditioning old bus plugs and obsolete bus plugs, is rust. Ironically this biggest challenge...

• Bus Plug Becomes Rat Hotel

  It would be more accurate to say the Square D bus plug became a mouse hotel, but Rat Hotel sounds more dramatic. MIDWEST field services runs into some pretty...

• Power Transformer – Visible Defect at Top of Winding

  MIDWEST frequently rejects equipment even thought it passes the electrical tests. Here’s an obvious example. MIDWEST’s Switchgear Shop rejected a 225 kva...

• Draw Out Air Circuit Breaker Lubrication Problem

  The over lubrication of low voltage draw out air circuit breakers drives the MIDWEST Switchgear Shop crazy. Sometimes MIDWEST gets these circuit breakers...

• Circuit Breaker Arc Chute Missing – Remove the Cover

  MIDWEST has its own internal blogosphere that especially hums away when something unusual happens, like when one of the Engineers or Engineering Technician...

• High Voltage Oil Filled Power Transformers Made with Wood – Surprise

  MIDWEST was called to check out an old 3750 kva oil filled transformer. The owner was trying to decide whether to reclaim the oil in the old power...

• Overheating 1200 Amp Square D Circuit Breaker – Bus Bolts Bottomed Out

  MIDWEST found a seriously overheating 1200 amp Square D circuit breaker during the annual Infrared Scan of a Foundry. The upper left corner of the newly...

• Will Not Test Only – From Bus Plug List of 10 Things We Will Not Do

  On MIDWEST’s list of “Ten things we will not do with bus plugs” is “We will not sell a bus plug that we have tested only.” In other words, we are...

• Dry Type Air Cooled Electrical Transformers Outside – How Do They Survive

  How does an air cooled or ventilated electrical power transformer located outside in the rain survive? Why doesn’t the rain cause an electrical short?...

• Water Damaged Bus Plugs – How Do You Know

  MIDWEST was asked how we can tell if a bus plug has been water damaged. What if a brand new bus plug is exposed to water, say rain. How can we tell after it...

• Important Circuit Breaker Maintenance Tool – Wasp Spray

  On a field service project, the customer was amazed at how much equipment we had on the large service vans. Besides the test equipment for old and newer...

• Replacement Transformer – Four Bolts Cost over $12,000.00 each

  This MIDWEST blog is about a low voltage, high current transformer used in a hardening process. The transformer was physically located deep in the process...

• Circuit Breaker Style Bus Plug Shorted with Wire

  About the craziest bus plug MIDWEST’s field services have seen was a circuit breaker style bus plug that had the circuit breaker removed and replaced with...

• Student wonders how oil can be used in transformers

  MIDWEST had a curious question from an engineering student about large oil filled electrical power transformers. He couldn’t understand why a 20 Mva power...

• Circuit Breaker Trash Barrel – Fried Load Terminal

  This is another circuit breaker trash barrel blog. I went to one of the many barrels of trashed circuit breakers and grabbed a breaker out of one of the...

• Why Disassemble Bus Plugs for Reconditioning

  MIDWEST was asked by a retired electrician why we bother disassembling a bus plug to recondition it. He worked for a contractor for years and they serviced...

• Circuit Breaker Broken Handle, Blasted Contacts

  We grabbed another circuit breaker out of one of the junk breaker barrels. This one was a Cutler Hammer KD3400. Again, at first the breaker looked clean and...

• 30 Mva Substation Transformer 138 kv to 13.8 kva vs Raccoon

  MIDWEST received an emergency call from a customer who had lost a 30 Mva 138 Kv to 13.8 Kv oil filled power transformer. There was no storm or other unusual...

• Cutler Hammer HND312T33W Circuit Breaker Interrupts 65,000 Amps

  MIDWEST had a call from a purchasing agent for a manufacturing plant. He was suppose to purchase a 1200 amp Cutler Hammer circuit breaker that he was told...

• Scrapping a 5000 Kva Oil Transformer Worth the Technician’s Experience

  We received feedback from a new Technician who was scrapping out an old 5000 kva oil filled power transformer. It was over 40 years old and hadn’t been in...

• New Circuit Breaker Nuisance Tripping, Trip Element Never Set Up

  MIDWEST frequently gets calls about brand new circuit breakers nuisance tripping. The owner often believes they have a defective new breaker, because it just...

• Transformer Manhole and the $25,000 washer

  This is a horror story from an electrical contractor about an event that took place around 1970. But the event reinforces the requirement to follow protocol...

• Circuit Breaker Trip Device – Hidden Defect

  MIDWEST asked our Switchgear Engineering Technicians for an example of a molded case circuit breaker that had a hidden defect that could only be found by...

• Bus Plug Neutral – You see it on the nameplate, but its not there

  We asked MIDWEST’s Switchgear Shop for an example of a replacement bus plug problem or defect that would not be picked up by standardized reconditioning...

• Replace Bus Plugs Due to Failure, Not Just New Load

  Much of the demand for reconditioned and new surplus bus plugs is because the user has to replace bus plugs that are defective. One of the worst things that...

• 20 MVA Transformer – Internet Doubles the Price

  The internet might be a great tool to find a replacement reconditioned or used 20 MVA transformer, fast. But the internet information could be deceptive and...

• Square D MAL361000 Circuit Breaker May Take 5 Minutes 40 Seconds to Trip

  MIDWEST had a customer call because they had an old Square D MAL361000 and it took forever to trip when they had a serious overload problem. He bet it took 3...