Tacho driven Overspeed relay

[star_watcher]

Can anyone reccommend an overspeed relay driven from a tacho? (It needs to protect in both directions)

 

[kamenges]

This might work if it isn't a critical application.

Keith

 

[BITS N BYTES]

Can anyone reccommend an overspeed relay driven from a tacho? (It needs to protect in both directions)

What exactly do you mean by "tacho".
Is this an analogue output?
DC or AC output?
Or do you mean an "encoder" with a digital output?

I pose these questions because I have seen many folks confuse a "tacho" with an "encoder".

If you are using an encoder!!
Just about any small model PLC nowadays with DC inputs should be able to handle this and at less cost than a dedicated "speed-switch".
Where we require a "speed-switch" function we now use a small PLC with built in adjustable potentiometerand connect the encoder to High Speed input of PLC. Pot can be used to adjust speed threshold and/or hysteresis around speed threshold.

 

[widelto]

Can anyone reccommend an overspeed relay driven from a tacho? (It needs to protect in both directions)

Do not know if you have a drive to control your motor, but you can try to use an analog output from your drive, use this as an analog input in your plc and if voltage is greater tham limit then motor is on over speed.
If you use no drive try using an AC tach, convert tach output to DC and then use a voltage divider, output from the voltage divider has to be used as an analog input on a plc and use it as above.

 

[Mickey]

Dynalco Controls should have what you need. See link below

http://www.mod-tronic.com/Dynalco_Speed_Switches.html