It’s not going to hurt your alarm clock. That’s the problem with a story like this: So few people are going to truly understand it when they read it. Unless you are using an ancient digital (looking) alarm clock that flips the numbers into place with a motor, you’re in good shape.
The standard design for 60 Hz (and 50 Hz) powered digital clocks is to use a phase locked loop to tie the internal oscillator frequency to the line frequency. If these clocks have battery backup, the oscillator runs open loop when it goes on battery and can easily gain/lose minutes per hour — chintzy engineers didn’t care. Anyhow, if the line frequency can no longer be relied upon, neither can anything that follows it.
“That’s the problem with a story like this: So few people are going to truly understand it when they read it. “
No the problem with this is the people making the decision don’t know the impact nor do they care.
Its not my job to be an expert on everything.
Well, there's a difference between "causing harm" and "causing inaccurate operation."
Melas wrote:
It’s not going to hurt your alarm clock. That’s the problem with a story like this: So few people are going to truly understand it when they read it. Unless you are using an ancient digital (looking) alarm clock that flips the numbers into place with a motor, you’re in good shape.
For clocks, I doubt there's any permanent harm. However, any "traditional dial" clock (with a big hand and a little hand, and maybe a second hand) which plugs in the wall is potentially affected. Most of those use a synchronous AC motor to drive the mechanism at a constant, known speed. They are accurate because over time, total cycles/total seconds always is very close to 60 cycles/second. There can be shorter periods when the frequency is off in one direction or another, but up until now, the totals were tightly regulated.
For digital (LED or LCD) clocks, the situation is more difficult to estimate. Any clock with a "battery backup" should be unaffected. Most of those have a quartz crystal timebase, so that they can continue to keep time when on the backup battery (a DC source). However, digital clocks without a battery backup feature are far more likely to use the line frequency as the timebase. Why add the expense of a quartz crystal and the associated circuitry when you have a (up until now) reliable 60Hz signal coming in on the power line.
You are probably correct. Anything with a synchronous AC motor will run at a speed determined by the line frequency. This could affect any device with a synchronous motor.
Bockscar wrote:
Something tells me it will ‘disrupt’ more than clocks.
For asynchronous motors, the affects will be more subtle and depend on the device. For example, for induction motors (brushless motors very commonly used where precise speed isn't needed), operating speeds are stable with load (IE, increased load will slow it down, decreased load will allow it to run faster) above the 'peak torque' speed. Above that speed, if you slow the shaft, the torque increases. This makes that type of motor largely self regulating for the load. Below 'peak torque' speed, operating speeds can be unstable with load. Motors operating in that range can stall out or the speed can oscilate, sometimes in unpredictable ways. The big issue is that 'peak torque' speed varies with power supply frequency.
This is not a change that should be implemented nationally on a "let's see what happens" test. There aren't a lot of positive outcomes, and there are a lot of risks of negative outcomes. This is a change that should be announced at least 10 years in advance, giving anyone who owns critical electrical equipment a chance to test the effects of supply frequency changes on their equipment. This also gives manufacturers lots of advance time to release new designs and document which of their devices need replacement for "variable supply frequencies" and which will continue to operate as designed in that environment.