Cycles per second meter

[pikis]

Hello fellow electricians,

Would anyone know how to connect a Nalder Bros & Thompson LTD London, please?
~The BS 89 is a tough book to obtain.

I wired the unit according to this diagram, which is the closest what I have.

This is the beauty in pics:

And this is what I thought to do next, plug it into mains:

The yellow and blue wires, (now replaced with brown and blue), where do they go? series to load on live wire or the way I have it could work too?

I hope you find this interesting and would be so kind to reply.
Thank you very much in advance
Pikis

 

[ipf]

Oh for Lucien.........right up his street.

 

[marconi]

Pikis- I strongly recommend you do not apply power yet especially from the mains because we need to confirm the technology of the meter in front of you and its designed operating voltage.

I think the wiring diagram you showed, which is for a moving iron mechanism type meter, is not what is in front of you.

The meter in front of you I think is a moving coil meter mechanism which uses direct current. There are hints to this because I believe the two blue cylindrical components to be metal type bridge rectifiers to turn ac in to dc to drive their respective meter coil.

Metal rectifier - Wikipedia - https://en.wikipedia.org/wiki/Metal_rectifier

The meter I think uses the ratio metric technique - see

http://sves.org.in/ecap/Resources/Frequency meters_74.pdf

To help, could you first carefully draw out what is connected to what please. The circuit diagram at the ratio meter slide is a guide to what I suspect you will draw.

 

[pikis]

Thank you both very much!

Oh it works, this time it shows 60 Hz,and UK cities' setup is ususally 50 Hz, so it's likely reading incorrect.
Could calibration, replacing part help (finding an original rare)? Can someone please point at where to look?

~It was the owner who plugged it to mains a few moments ago~

Thank you very much in advance
Warm Regards

 

[marconi]

Try swapping the 0.25uF 350V dc capacitor for a new one such as this:

Vishay BFC2 368 55224 220n 400V 368 Series Polyester Capacitor - https://www.rapidonline.com/vishay-bfc2-368-55224-220n-400v-368-series-polyester-capacitor-10-4136

(220nicoFarads is 0.22microFarads - 0.22uF).

 

[marconi]

I should point out that the meter connected as it is by its two terminals to a lead and 13A plug does not meet today's safety standards. Those terminals are exposed live parts. Similarly, if the meter mechanism is made of metal and its front face too then it could potentially be live. What is your intention for the meter once you have it working? You can buy safe plug in frequency meters such as this one:

https://www.amazon.co.uk/Monitor-Ba...3&psc=1&mcid=b0886befc02a36868851baac5fb20dde

 

[ipf]

I know it's a BS plug top but I'm wondering where 'SE' is, exactly.

Whatever, I don't like all this piddling about with mains voltage.

 

[pikis]

Thank you both.
I will get the capacitor and advise them to let me try make it safer.

Warm Regards