What did we use before encoders?

[CMcF]

I have embarresed my self in front of a young electrical engineer. I can not remember the name of the analogue equivalent of an ecoder?

 

[mikek10]

You mean potentiometer?

 

[ScottyUK]

If you're measuring angle then perhaps a resolver or an RVDT. If measuring speed then a tacho generator would fit the bill.


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If we learn from our mistakes I'm getting a great education!

 

[CMcF]

Thanks cottyUK,
It was a tacho that I was thinking of.

 

[eromlignod]

You can still get tach generators. I just used one on a recent project as feedback on a shunt-wound DC motor. They're getting harder to find now though.

A resolver is also an option if you want to get fancy.

Don
Kansas City

 

[SomptingGuy]

... or an inductive probe targeted at gear teeth.

- Steve

 

[sreid]

A resolver or a synchro?

 

[Cockroach]

In the good old days, mid seventies, I use to just use a magnet attached to a rotating shaft and a loop of wire. Connect to a volt meter and wait for the needle to deflect. Counting the spikes in a minute gives you RPM. Same principle applies today, just fancier equipment.

Good luck at high speeds!

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada