"i don't care if it does have silver contacts, relay/solenoids handling that kind of current will not even come close to a million cycles, quite frankly depending on various issues relating to climate, mounting, etc,, the relay might do well to make a few thousand cycles before it fails."
Makes them fork lifts, floor scrubbers, electric people movers, starter motor relays and a host of other things they are used in redundant I guess.
I have seen them do 25 years driving dead switched loads of over 200A/36v and 48v for a few hundred cycles per day for day in day out duty in floor scrubbers and forklifts.
I've also seen a lot fail near new.... but mostly they last unbelievably well under horrendous conditions.
I also use then to short my mill out when the electric car is charged.... which uses them for forwards and reverse and power on.... and they came out of an old windsor ride on floor scrubber... circa 1995... and it used to clean Melbourne airport 7 days a week.
This style of industrial relay are mostly pretty good. A lot of them are switched at zero current now days, but in the good ole days... they splat start 4kw dc 48v motors all day every day... for decades until solid state switching (speed control) turned up. Before that, even speed control used 3-4 relays and resistors. The brush/roller broom/scrubber head motors were all splat start under full load.
Starter motors are under the same duress, and before they began putting the start solenoids integral to the motors, they lived on the firewall... that type of relay in the photo.... they did pretty good... I never replaced one, but I know those who have.
In short. I don't share your same disdain.
If the hysteresis is set short so it chatters irresponsibly , it's a different story... and if you get a resonant frequency going.... well the solenoids are so powerful, they will hammer the contacts to death eventually. I don't recall seeing silver in these devices....just big lumps of copper.
If your going to pulse them rapidly then use something else. If you give em 5 min on/off etc, they will last a lot longer than you expect. (fork lift is usually a few seconds to 10's of seconds before cycling. My fork was over 20 years old when I sold it... never did the relays.
When the world moved on, and mosfet switching became the in thing in floor equipment, if you were called out for a dead motor... it was always the mosfets gone... never the big relays they still used for forwards/rev and on (and for when the fets blew in full on state... don't want to drive through the shop windows). If it was a H bridge design without relays.... you knew the thing wouldn't make a year.
.........oztules