So a LONG time ago, the old "N" type OL heaters had the solder pot and pawl in the relay base and just the heater element was placed over it. So if people got annoyed with nuisance tripping, they'd keep increasing the size of the N heater element until they would literally cook away the solder by over heating it until the seal on the pot case melted (let's leave out the motor damage issue for this). In the early 80s, A-B changed to the "W" elements, in which the solder pot and pawl are on the replaceable element part, the relay base only holds the ratchet and contact mechanism. So when you replace or increase the size of the W heater, you are also replacing the solder and pot, therefore repeatedly trying to make it fail is less likely to succeed. The motor damage still happens of course...
Seen that before. Got a service call one time on a product auger that kept tripping motor overload, and they needed to get their run of product done because a truck was coming same day to pick up that product. Might have taken 30-45 minutes for me to get there. Starter was in a location remote from the motor and at that point they had dedicated one employee to sit in front of the motor starter and reset it as soon as it tripped.
When I started doing industrial work in 1978, the 509 starters (where they began using the W heaters) were not yet released. When they did, it was a total PITA for us, because we had thousands of 709 starters installed with N heaters. So we had to build a new huge rack to start holding the Ns + the Ws for a few years. When I left the steel mill, so few of the 709s remained that they merged the racks into one, and I took the old rack for the Ns home and made it into a spice rack. Still have it to this day.... and LONG time ago is a matter of perspective.
