In the general world of consumer electronic devices there is a game of high numbers played to entice buyers, referred to as specsmanship. Audio power amplifiers are a great example as young male buyers are enchanted by high power specifications. As a practical matter machines in normal use do not draw their maximum power very often if ever. In order to blow a properly operating breaker there is a significant time delay involved. Whilst there are electronic circuit breakers which have precise blow characteristics, thermal and magnetic breakers take a while to blow. For instance a 15A breaker when loaded with 15A will be expected to blow in about an hour.
If the machines were commonly blowing breakers because of normal loads then there would be a very high rate of returned units. 3270 Watts is a HUGE amount of heat in the context of motor efficiency and an amount which would certainly bring damage to the motor. Also, most motors have an overtemperature sensor which will blow if a certain temperature is reached. Various international agencies have strict safety rules that must be tested and proved.
B. I don’t believe anyone can answer your question for you – here’s why. An AFCI is not a specific device, it is a category of devices. Lets say someone has a miter saw that has never tripped an AFCI for them. Does that mean it will not trip an AFCI for you? Not necessarily. There are multiple brands and types of AFCI’s, made with different hardware and more importantly different firmware. Made over many years – older AFCI’s were more prone to false tripping with brushed motors. So I would never trust anyone’s opinion on your question. There are simply too many variables for any person to know the answer you your question.
If you want more information perhaps you can buy a couple units and set up a bench test that would allow you to measure the locked rotor load value (peak) and observe time to burn up or blow the overtemp sensor in order to satisfy your curiosity. Combine that with the circuit breaker manufacturers specification to fully answer your question.
AC excitation current sets up alternating flux in the core which itself links with the primary and emf is induced in it. The excitation current is such that the emf induced is equal and opposite to the applied voltage. This is the magnetizing current(very small when compared to full load primary current) which lags the applied voltage by 90 for ideal transformer. Only after the secondary is connected to a load does the primary draw additional equivalent primary current.
Circuit breakers are thermal devices. They contain an element that heats proportional to the load passing through. The more current flowing through, the faster it heats. When a certain temperature is reached, the breaker trips. This creates a time factor; the greater the load, the sooner the element heats and trips the breaker.
If the circuit has a 21A continuous load, it may carry that liad for a minute or so, as the element gradually heats to the tripping point. This is not unsafe; the wiring protected by the breaker can generally withstand overcapacity for a period of time.
In the case of the electrician’s pliers, it is possible that, though the pliers might represent a dead short and thus heat the breaker quickly, the force of the arc (or the muscles of the electrician) pushed the pliers away and broke the arc before the breaker heated to the point of tripping.
Traffic light sensors aren’t exactly magnetic, but the principle is similar. They work by closing an induction loop in the sensor when a metal object (like the underside of a vehicle) is placed over top of the loops in the road. A bicycle will work just as well, if you know where to place it. If your area uses loops with cut-outs in the road (Toronto does, I don’t know about elsewhere) you will be able to see a groove in the surface of the road that forms a square loop, or sometimes two loops side-by-side. If you stop your bike on top of the groove, you’ll trip the sensor.
When two GFCI circuits are connected in series and there is a ground fault downstream of the pair, there is a race. Both are supposed to trip, but the likelihood of both tripping at “exactly” the same time is small, for any number of reasons. The GFCI that happens to be the quickest is the one that trips, either downstream or upstream. It doesn’t matter. Once the first one trips, the second one has either no fault, or no power or both and cannot trip.