A neat small desktop alarm clock, this ITT Nova GB 13.
It is a 12 hour roll clock with a 24 hour alarm. The red/white indicator left of the hours indicates whether is it day or night. The button on the left sets the alarm and when pushed in also adjusts the time. I have seen the same clock also branded as 'Good old Electric Model GA 13' or as 'M-Digital Migros'.
The mechanism and the motor were new to me, never seen these before. Major parts of the mechanism are made of plastic, including some axles. Nevertheless feels quite well build.
I bought the clock in not working condition. The motor was running but a gear was broken. To make matters worse it appeared that someone had tried to fix something using super glue, then spilled the stuff and glued two gears completely stuck!
The smaller gear of the brown double gear appeared to be missing, but I found a small bit of the remains somewhere back in the case.
Luckily super glue does not bond very well with POM, so I could easily separate the two gears and then tediously clean all teeth using a needle. At least the white gear was saved but for the brown double gear I needed to find a replacement. This I could order at kkpmo.com in Poland, but first I needed to determine the gear dimension. For the large gear this was fairly easy as I still could count the teeth and measure the diameter.
But for the small gear this became a bit of a puzzle as there was hardly anything left. The module was easy to determine as I could determine it from the large white gear (which is a good idea anyway as it is more accurate). The number of teeth though I was not exactly sure about, could be 10 or 11. To resolve that I then reasoned that if I knew the in and outgoing rpm and the number of teeth of all other gears in-between I could calculate the missing number. The outgoing speed was simple: this is the seconds wheel and thus 1 rpm. The speed of the motor was not given, but on wikipedia I learned that you can deduce this from the number of poles and the net frequency. Knowing this and after counting the teeth on each and every gear, I could do the math and determine it had to be 10 teeth. So I ordered the gears at kkpmo.com (doubling the price of the clock, but I found it still worth it) and with these got it working again. It is running fine since then! (and at the right speed
)
It is a 12 hour roll clock with a 24 hour alarm. The red/white indicator left of the hours indicates whether is it day or night. The button on the left sets the alarm and when pushed in also adjusts the time. I have seen the same clock also branded as 'Good old Electric Model GA 13' or as 'M-Digital Migros'.
The mechanism and the motor were new to me, never seen these before. Major parts of the mechanism are made of plastic, including some axles. Nevertheless feels quite well build.
I bought the clock in not working condition. The motor was running but a gear was broken. To make matters worse it appeared that someone had tried to fix something using super glue, then spilled the stuff and glued two gears completely stuck!
The smaller gear of the brown double gear appeared to be missing, but I found a small bit of the remains somewhere back in the case.Luckily super glue does not bond very well with POM, so I could easily separate the two gears and then tediously clean all teeth using a needle. At least the white gear was saved but for the brown double gear I needed to find a replacement. This I could order at kkpmo.com in Poland, but first I needed to determine the gear dimension. For the large gear this was fairly easy as I still could count the teeth and measure the diameter.
But for the small gear this became a bit of a puzzle as there was hardly anything left. The module was easy to determine as I could determine it from the large white gear (which is a good idea anyway as it is more accurate). The number of teeth though I was not exactly sure about, could be 10 or 11. To resolve that I then reasoned that if I knew the in and outgoing rpm and the number of teeth of all other gears in-between I could calculate the missing number. The outgoing speed was simple: this is the seconds wheel and thus 1 rpm. The speed of the motor was not given, but on wikipedia I learned that you can deduce this from the number of poles and the net frequency. Knowing this and after counting the teeth on each and every gear, I could do the math and determine it had to be 10 teeth. So I ordered the gears at kkpmo.com (doubling the price of the clock, but I found it still worth it) and with these got it working again. It is running fine since then! (and at the right speed
)
Comment