My signature used to read,Simple and idiot-proof at the same time.
A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.
My signature used to read,Simple and idiot-proof at the same time.
A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.
Not that well designed IMO, if operated repeatedly it stresses and heats the motor.Simple and idiot-proof at the same time.
Another quote: "There's nothing so dangerous as a resourceful idiot".My signature used to read,
a plugging switch is to prevent instant reversal. a lot of equipment here takes very unkindly to trying an instant reverse. so the plugging switch detects the very low speed or stopping of the motor before allowing reversing.Plugging traditionally on a 3 phase motor is instant power reversal.
Max.
there should have been an interlock to prevent foreward and reverse at the same time. sometimes built into the switch, but usually in the reversing contactor.The bloke who took it apart and couldn't put it back together was a bit offended when I mentioned how simple the switching arrangement was.
You don't neccessarily need to be an idiot to inadvertently press both buttons at once, the winch was for hauling broken cars onto a recovery truck - vehicle recovery doesn't always go smoothly, particularly in pitch darkness and filthy weather. Just as the car starts to topple sideways off the truck, its an instinctive reaction to press everything at once trying to stop it.
Then there's always meddling kids that sneak up while you're not looking.
The buttons operated directly the high current contacts, You could put a see-saw lever between the buttons so pushing one button down pushes the other one up - but that could lock out the motor braking that was designed in if both buttons are pressed.there should have been an interlock to prevent foreward and reverse at the same time. sometimes built into the switch, but usually in the reversing contactor.