|
|
Subject:
Modfying clock motors
Category: Science > Instruments and Methods Asked by: sarra21-ga List Price: $4.00 |
Posted:
01 Apr 2004 16:41 PST
Expires: 01 May 2004 17:41 PDT Question ID: 323823 |
How do I make a regular clock motor speed up and/ or run counterclockwise? |
|
Subject:
Re: Modfying clock motors
Answered By: redhoss-ga on 01 Apr 2004 20:51 PST |
Hello sara21, randymc's comment would be true for a battery powered (DC motor) clock. However, most clocks are powered by your house's AC electrical system. If you are in the USA, your home power is 120 or 220 volt 60 cycles per second. Your clock motor is what is called a "synchronous motor". Changing the wires will not change the direction of rotation. The speed of the motor can only be changed by varying the 60 cycle frequency. Lower frequency the motor runs slower. Higher frequency and it runs faster. To accomplish this you would need a variable frequency power supply. Actually if you were to monitor your home power you would see that the frequency does vary slightly at different times of the day. Your power company regulates the frequency so that everyone's clocks don't gain or lose time over a day. If you are interested I found a very interesting article about the evolution of clocks: http://clockhistory.com/telechron/company/documents/warren_1937/ Hope this answers your question. Redhoss |
|
Subject:
Re: Modfying clock motors
From: randymc-ga on 01 Apr 2004 16:53 PST |
To make it run counterclockwise, reverse the wires from the power source. |
Subject:
Re: Modfying clock motors
From: neilzero-ga on 02 Apr 2004 06:46 PST |
I'm not sure there is a regular clock motor. At least 5 designs are in common use. I don't think any in common use run backwards if you reverse the battery. You can buy a box (for a few hundred dollars) that produces 120 volts ac at adjustable frequencies from a few hertz to about 400 hertz that will run the type of plugin clock popular 1935 to 1980 (over part of that frequency range) A few of this old type of electric clock are still made for 50 hertz and most of them will run 20% fast if you operate them on 60 hertz. The local power company needs to disconnect from the North American grid to change frequency even a few parts per million. I suppose someone in each region, instructs specific power plants to lead or lag the grid phase by about one degree to keep the frequency of the grid plus or minus a few parts per billion. Some clocks have a fast/slow knob or lever, but the adjustment possible is probably smaller than you had in mind. You could cut a big hole in the clock case remove a few gears and replace them with a different gear train mounted outside the case. Few people have the know how to design a external gear train that would be reliable, and chances of being able to find an an already made train that will do the job are extremely unlikely. Generally it is not practical to make clocks run backwards or at different speeds, except at a clock factory where it could be done for a few thousand dollars whether we make one or several thousand of these strange clocks. Neil |
Subject:
Re: Modfying clock motors
From: jaybug-ga on 25 Mar 2005 22:42 PST |
You might try to find an old "non-self starting" clock. These are restarted after a power failure by spinning a starting knob. If spun backward, the clock will then run backward, until the next power failure. I believe that the self starting synchrous motor was invented about 1920, so you would search for an electric clock built before 1920. You would be wise to have the power cord replaced before pluging the clock into your wall socket, because these old power cords were just wrapped in cloth, which will probably have rotted. The motors used were synchronous, so the speed will be the same, but in the wrong direction. I was able to purchase one of these clocks for about $20 dollars on Ebay. The power cord had already been replaced on mine, and this beautiful old clock runs perfectly. Jay |
If you feel that you have found inappropriate content, please let us know by emailing us at answers-support@google.com with the question ID listed above. Thank you. |
Search Google Answers for |
Google Home - Answers FAQ - Terms of Service - Privacy Policy |