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Agroshield
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"Just for powering a digital tacho on the lathe."
It would be an unwise move to attempt to use the VFD's 10v supply for anything but controlling the VFD.
It would be an unwise move to attempt to use the VFD's 10v supply for anything but controlling the VFD.
timgunn1962
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DC on every one I've ever checked. O-10VDC (or 2-10V) is a pretty common industrial control signal and using 10VDC allows the VFD manufacturer to cover both 0/2-10V and potentiometer inputs without adding any extra components. Adding a 5k Ohm resistor (sometimes already incorporated into the drive, sometimes fitted by the installer) allows the use of 0/4-20 mA (the other common industrial control signal).
daleyd
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As said above the 10v "supply" generally won't be for anything other than providing an analogue out signal, not for powering anything. I used inverted commas for supply as in my experience its not what you would traditionally call a supply.
Typically the output will be programmed to vary with speed, amps or some other variable, and would be used to retransmit that info to a plc, or some other measuring device - it could well provide the info to a tacho but that tacho typically would also need a separate power supply from elsewhere.
My experience is mostly with schneider/mitsubishi/Siemens drives, maybe others are different though.
Typically the output will be programmed to vary with speed, amps or some other variable, and would be used to retransmit that info to a plc, or some other measuring device - it could well provide the info to a tacho but that tacho typically would also need a separate power supply from elsewhere.
My experience is mostly with schneider/mitsubishi/Siemens drives, maybe others are different though.
Thats fine fellas, thanks. I had already bought a little 12v out transformer for powering the tacho, think it is for lighting actually, but then I thought I was an idiot for buying as there is a 10v terminal on the vfd, just for curiosity asking if it is ac or dc.
Seadog
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My tacho has been powered from both a TECO, then an Optidrive when I uprated the motor.
The current drawn is milliamps.
daleyd
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There’s usually a 24v supply from the drive that you can use to power low demand stuff, but the 0-10v output is variable (programmable for various stuff usually), so unlikely to be suitable for powering anything,
Just for the fun of it I tried the 10v on the vfd with multimeter set to 20v dc.
With the positive test probe on the 10v terminal on the vfd and the neg on ground it showed -10v. Swapped the test probs and it showed 0, swapped again to original and it still showed 0. I don't think I will ever understand electricity.
As I alredy said, it dosent matter, I am not going to use the 10v on the vfd except for attaching a pot.
daleyd
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If it’s a 10v permanent supply then it’s possible, the pot supply is usually 5v - but probably different between manufacturers - but that’s just what I’m used to. Usually when Ive seen 10v on connection diagrams it refers to the variable Analogue Output.
It will certainly be dc rather than ac, as you’ve already discovered.
When doing this for work, there’s almost always a separate 24v supply, so it would be unusual to have to use the drive to feed anything other than its own inputs and outputs. Obviously not saying it can’t be done - as others have done above, but it wouldn’t be common.
