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You'll just embarrass your customer, he's wrong, so don't push it. Instead, run a simulation using some decent EE software and give him a generous interpretation of the result. The "garbage in, gospell out" effect will dispell most doubt, and it wasn't his error.

Experience in a breaker shop, we had a number of older power plants and pipeline stations as customers. The ones who had modernized old lineups, replacing old breaker-as-starter units with new vacuum-breaker-as-starter units had much sorrow and woe. The mechs are made of stamped sheet metal...

You can run coupled to the grid with droop controls on both power and voltage, but unless the grid is very stable at the point of interconnection you wouldn't want to do it unattended. A far better setup is to use feedback control of both real and reactive power. Meanwhile, the protective...

Just because there are three PTs doesn't mean they are all being read. Make sure the relay knows there are three! Yes, it happens.

Modern breakers are not built like the old ones. The vacuum bottles will take many operations but the mechanisms will wear out. For this kind of duty choose a contactor, not a breaker, and back it up with fuses if necessary.

Last time I saw AC on the DC bus it was in a lineup of medium voltage switchgear with 48VDC floating control power. Somebody had modified one of the units to be a motor starter. In the process they re-wired about half of the control panel to run from the local control power transformer...

Mathematica, perhaps?

Soundslike these may be Magneblast breakers? They are very prone to having the trip mechanism stick and burning out the trip coil, the seal-in coil on the relay, or both. It is also possible that the target was left down after a scheduled test of the relay. Has it recently been tested? When...

When you hook up a two element meter to a three-phase circuit with the typical open-delta PT arangement the voltage triangle is offset because the B corner is grounded. This is irrelevant when computing energy in a three-wire load circuit, in principle. In practice, the effect is that the...

The older AKR breakers hold up to rebuilds well. There are a lot of them in the junk yards so you'll be able to keep it going for years. For 480V service there is room for both a vacuum contactor and a set of fuses on the frame, but you have to modify the platform some. You can have the shop...

No, I'm just suspicious. Why are they selling those motors at that price to this customer at this time? Probably trying to get the design-in, might be dumping, who knows? But the engineering decision is being biased toward the induction motor because of the below-market price offered for...

Because hydrogen is less dense than air it is not centrifuged out of the rotor as much as air. Helium also has good thermal properties and is inert, but it is twice as dense as hydrogen. Is density the determining factor?

We never see BF in industrial systems. We'd like to, but the systems are usually pure radial and the breakers are more reliable than the never-exercised transfer trip circuits would be in practice. The single-failed-bottle scenario won't clear a ground fault on the bad phase. That means that...

When checking the calibration of a two-element meter with a single-phase source, you need to energize both potential coils. There is an adjustable shading coil on the potential coil cores that is used to generate torque to cancel the friction in the shaft bearings and register. Your low-power...

Most vendors call this function "pull out" when it is applied to a motor, the "out of step" terminology is usually seen when it is applied to generators. The settings are seldom critical. The relay's job is to trip out the field and/or the main supply when the motor "pulls out of sync". This...

The usual justification for a sync motor is based on their stiffness with respect to cyclic torque variations. Reciprocating compressors and certain kinds of mills are the usual applications we see. Back in the day they used sync motors as something akin to a virtual gear train to maintain...

The ideal CT is impervious to nearby magnetic fields. Real ones aren't. When clamped on near a transformer or motor you will get some influence. I've had "fluctuations" in measured current that weren't really there twice in the recent past. Once due to the influence of a contactor coil and...

The selection of the GFCT depends on how your system is grounded. You need to know minimum and maximum GF currents. I second the recommendation for a Multilin 239.

OK, I'll bite. BSEE, MS Applied Math, working with a lot of sync machines these days. Do you just need the math or do you need it programmed into some particular simulation environment?

Best piece of advice I've seen on watchdogs is to split the "set" and "reset" operations between separate sections of the code. Make the hardware timer require transitions so the process has to execute in both sections to keep it reset. One system I built had numerous communicating processes...