Thread: VSD enclosure

So it measures the voltage across 10V - MVI and the voltage arcoss MVI and ground?

The third pot was so I didnt need three wires between the VSD and the machine.

Might not be doable

Thanks

Stuart

Hi Stuart,

You can actually do it with just two wires. Ground and control voltage, is the absolute minimum you need. But to do that you would need to generate an extra +10v supply at the control box.

The external supply for the +10v, is easy enough to do, but it would need to be well regulated and filtered. A 7809 regulator (9V) with a diode (9+1.2=10.2V) in the ground leg will suffice, if you can get 12v from somewhere. Current required is just a few mA,

Can you give a quick run-down on what the other terminals on your connector are for.
Might be an option there to free up a wire for the +10v power supply.

Regards
Ray

The only machine that has 12V is the mill and it will have its speed limited by the VSD.
The lathe in 24VAC, the shaper is 32VAC
So a bridge, cap and resistor wont cut it?

8 pin dins plugs with usb wire
1 & 2 The machine control voltage (this means the machine controls cant be turned on as the inverter is switched to it and allowed me to switch the relay for the speed control wires.

3 12V
4 Fwd
5 REV
6 switchable FWD REV on the enclosure(I guess this one can go and just put FWD/REV switches on each machine. The lathe will already have it. The drill and shaper wont need it. That just leaves the mill)

7 & 8 inverter Hz speed control wires

Stuart

Hi Stuart,

The 12v, I assume is the 12v supply to the multi-function inputs on the VFD.

You could use that to generate the speed reference voltage with just the addition of an extra resistor.

Your pots are 10k so a 2k2 in series with the max-speed pot will get you pretty close to 10v.

The quick and dirty version of this (attached) is fraught with potential problems, there is the possibility of noise and switching spikes getting into the control voltage input. Also I'm not sure how well regulated the +12v supply is. The motor generally doesn't respond to short term changes in control voltage, the acceleration/decelleration ramps tend to dampen things a fair bit.

A better solution would be to build up a +10v regulated supply. But if you just want to quickly get it working then just one resistor will do until then.

Regards
Ray

Thanks Ray
As you can probably tell by now, I tend to let the smoke out of anything more complicated than a bridge, so I think I'll drop the Fwd/Rev wire and use that for the 10V.
I hope you know its most likely going to stuff up my beautiful numbering system

Thanks again for your time.

Stuart

How is the VSD / VFD going for you these days, I take it that it all got finished and you've happily been using it out in the shed to make a makerbot, or some such thing

I'm looking at it for my bandsaw https://www.woodworkforums.com/f27/ce...-450nl-166960/

Curious too as to how much effort it is to get a VSd / VFD wired up to run a single machine with a single speed 3 phase 415V motor. I think yours is dual speed which would make it a little more complicated?

Cheers

Hi Simonmags,

Wiring one up for a single machine is far easier than what you see in this thread. Most of what you see would go in the bin if it was just running one machine. Both machine I have on it are single speed though that wouldnt change much.

I've had a quick look in your thread and will ask some question over there.

Stuart