There are motors in my plant that are fed straight from a breaker box, through a 3 pole paddle switch (motor switch), and that's IT... they've been that way for 30 years. As far as I know, if the breaker and wires are sized properly for that motor, it's fine. ...<snip>
PS, I really would not be surprised to find out I'm wrong about it being "fine" in this day and age, but it HAS worked for a long time. I'm always ready to learn something though.
It may indeed have been acceptable 30+ years ago, it's theoretically still possible if all the stars align in terms of breaker ratings and motor sizes, but I have never seen it work. The rules have definitely tightened up over the years. You may be grandfathered in now but if you change anything, you may find yourself in a heap of hurt.
The down side is... by the time that breaker trips, the motor... well... I don't know if you've ever tried to get that smoke back into a motor... but I've never seen anyone who could do it.:happyno:
Aaaaand there you go. I guess the cost of down time is irrelevant to your company. Either that or they carry a stock of spare motors with quick disconnect plugs on them for swapping them out quickly. It might be worth investing in some proper motor protection...
Just FYI, this is a chart of survey results of the average daily cost of downtime by different industries. Divide that by your daily work hours to see how much they are "saving" by being cheap on the OL relays.
The colors have to do with the number of employees in the companies, i.e. 0-30, 31-50, 200-300 etc. You can download the complete paper for free from
here. or view it as an image file
here.