Making 60Hz from 50Hz

[Hartley118]

I have a number of vintage Smiths Sectric synchronous clocks and they still keep accurate time.

So I guess that the Grid folk are still maintaining long-term 50Hz stability.

Martin

[Refugee]

... strobe it to a neon lamp with a strobe mat for the local mains frequency ...

But surely, it isn't the local frequency that you want to lock it to?

Here's a 'dual standard' version you could print:

That dual standard strobe card looks like it would come out of a box containing a DC servo turn table intended for the international market.

The original turn table we started with is a shaded pole type and if it were supplied with a strobe card it would have been a 60Hz one. What we need is a 60Hz oscillator and an amplifier with the correct transformer for the voltage the motor was made to run on. It would then need a 50Hz card and strobe lamp to set the speed to local UK mains using a trim pot on the oscillator. A quartz clocked counter could be used if you already have one and can't be bothered to print a card.

[ppppenguin]

The grid maintains the correct number of cycles in each 24 hours. Not sure when the reference time is but possibly 9am.

[Nick]

The grid maintains the correct number of cycles in each 24 hours. Not sure when the reference time is but possibly 9am.

I know that USED to be the case, but I can longer find a definitive statement to that effect - do you have a reference?

[ppppenguin]

I might be able to get a definitive answer from a friend who works at grid control.

[Terry]

I was always told it was 8am, which would make sense as the demand would just be ramping up at that time.

By 9am, the demand is virtually at its maximum, so the frequency might already be starting to sag again.