This question floats up to the surface of my murky mind every year about this time.
I was told as a child never to turn an electric analog clock backwards. Because my folks were big on “because I said so” as a rationale for things they told me, I imagined that it had something to do with damaging the electric motor that made the clock run.
So, two questions.
[li]Is there any basis in reality for this ban on turning an electric clock backwards?[/li]If so, what’s the real reason?
Well, they probably meant not to set it back while it was plugged in, because if the setting stem does not have some sort of clutch, you are briefly stalling the electric motor. This will eventually (long, long time) burn up the little brushes in the motor. Even rolling it forward will sometimes stop the motor briefly as you set the clock. And you know, since electric clocks cost a bazillion dollars, it is prohibitively expensive to replace them two or three days sooner than when they would have normally died.
More than likely, it had more to do with you messing with the clock in the first place. Speaking as the parent of four inquisitive children, the last thing you need is children who want to help out by setting the clock for you. Especially when you have to get up in the morning and go to work.
Now that you’re an adult, though, you get to do all the stuff your parents told you not to. Plug that clock in and set it back and forth all you want. Just don’t let your kids find out.
I used to have a clock like that. It plugged into the wall rather than take a battery like today’s clocks do. It had a lot of gears inside, not at all like today’s clocks. The instructions (from the manufacturer, not my parents) said to never turn the hands backward, only forward. In violation of the instructions, I tried. The hands only moved back a few minutes then the movement jammed. I moved them forward to free up the mechanism. So I never moved the hands back at “fall-back” time. But I did move the hands back just a tad when I was adjusting the time during the year.
My current analog clock came with no such instructions and I can move the hands back a full hour with no problems.
The most horrendous electric clocks I’ve ever had to deal with were very old fashioned time clocks.
There was a master unit which sent signals to all the display clocks and also the punch machines, plus things such as external lighting and watchmans pegging units.
You had to move the time forward in blocks of 1 hour when the second hand crossed the 12, so that to go backwards 1 hour involved 23 time advancements, get it wrong and you had to start all over again.
On top of this you then had to change the date and day markers(what you did was to remove the relay that operated the day/date mechanism and the put it back when you had finished but if you got it wrong you had to disconnect bits of the circuit, and push the relay mechanism by hand until it ratchetted around to the correct position)
…but to anwer the OP, some electric clocks have worm gear reduction, if you try to force them in any direction they will break.
I believe most electric clocks use synchronous motors, are are thus brushless. Even so, you’re correct that it’s not good to stall the motor…
And the real answer is: Electric clocks, like clothes washers and like bicycles, have a ratchet which allows the motor to push the device but allows the device to move ahead of the motor without moving the motor. So, if you push backwards, you will try to force the motor backwards and break the gears, but you can move it forward and the ratchet just lets it move forward.