Using Preet Speeds on a VFD

You are describing a single deck switch, that has a single input and outputs to each rotation position as it is turned for one input to the VFD. You need a switch with at least 3 decks since you have three separate inputs to your VFD that need a signal, the number of positions doesn’t matter as long as it is 8 or more, you can put in stop pins to only use 8 positions in a 12 position switch for example if you find one of those in stock at a better price. Each deck would control one of your inputs to the VFD. You would wire it up with the common from the VFD going to the input of switch, the outputs only get wired for the position that needs a signal going back to the VFD. Assume the first deck is for TB3-1, you need to wire positions 1, 3, 5, and 7. You can daisychain the wiring on each deck, ie connect 7 to 5 to 3 and to 1 with a single wire going from 1 to the VFD. The next deck would be wired to 2, 3, 6, and 7. And the third 4, 5, 6, and 7.

This is the datasheet for a switch that looks like it would work.


I found this at Digikey, Mouser and Newark would likely have something too.

71ADF36-03PAJN | DigiKey Electronics

Order today, ships today. 71ADF36-03PAJN – Rotary Switch 2 ~ 10 Position SP10T 250mA (AC/DC) 115 VAC Panel Mount, Through Hole, Right Angle from Grayhill Inc.. Pricing and Availability on millions of electronic components from Digi-Key Electronics.
www.digikey.com www.digikey.com
 
Rick_B said:
Some more stumbling around on the internet led me to a pdf from Digitran where they described various rotary switch outputs and how they work. I found one where there truth table match the VFD parameters exactly - it was described as a binary code octal 8 position. I found some at mouser (https://www.mouser.com/c/electromechanical/switches/coded-rotary-switches/?number of positions=8 Position&srsltid=AfmBOorcedhXK1dZwv5WoEXA6r-vwSnxX-zJw7iokaVgbvU4xZ_duClj) but can't see how they mount. I need a panel mount version.
Rick
Click to expand...
Those are meant for PC boards, the one I posted above should do what you need.
 
Ischgl99 said:
Those are meant for PC boards, the one I posted above should do what you need.
Click to expand...
So I thought I understood - now I'm bleeding out my ears. :)

Not arguing with you but presenting what I thought I knew. I understand the switch I linked is for PC boards but let's talk about how it I think it operates. The VFD Common (TB3-3) sends a signal to the switch. The VFD is expecting a return signal from the switch to some combination of TB#-1,2 and 4 - the combination corresponds to the truth table in the manual. For example (based on the manual default numbers) a return to 1 and 4 would generate a frequency of 50 hz. Now the switch - it receives a signal from the VFD and the switch position determines what combination of TB3 terminals receives the return signal. Based on the digitran PDF for a binary octal 8 position switch - switch position 5 would return a signal to the TB3 - 1 and 4 terminals resulting in a frequency of 50 hz.

I'm lost with the single versus multiple deck example you used - but getting me lost is pretty easy.

Rick
 
Rick_B said:
I'm lost with the single versus multiple deck example you used - but getting me lost is pretty easy.
Click to expand...
Look at the datasheet I posted, you’ll see multiple rows of connection points, each row is a separate deck, or one input to the VFD. Each deck takes the common from VFD and distributes that to each contact point depending on where the dial is positioned, ie in position 1, the contacts in position 1 in each deck has voltage. You only wire to the connector at each position of the switch on each deck you want to send the signal to the VFD. So, if you have an 8 position switch and 3 decks, you will have 24 output pins you can potentially use. However, you only want to use the ones in the truth table that are needed.

The one you posted will work, but how are you going to mount it and actuate it? You want one that is easy to use and can be panel mounted. If you can find a panel mounted octal switch, then it should work, I was only searching for panel mounted switches and didn’t see any in my search results, so not sure what is available.
 
Thanks for the multiple deck explanation - I think I understand better how that would work. To be honest in the current application I really don't need all of the preset speeds. It is an osscilating spindle sander and the VFD has other, less convenient, methods for frequency adjust that will probably be fine for the times I want to reduce speed. I could not justify the cost of the switch you linked - I just thought it would be an interesting exercise to set up the preset speeds. I agree that I can't find a binary coded octal switc in a panel mount version.
Rick
 
I assumed this was for a lathe or mill and you would want all those speeds, for a sander, two or even three speeds might be plenty. You can use a simple selector switch, or a toggle switch, I think I’ve even seen them at Home Depot, to do a high / low range. High would be preset 0 and the low range preset 1 where you only need one wire connected to the appropriate input.
 
You are right - I was originally planning on activating all 8 speeds - not for any good operational reason. But after thinking about it and considering your opinion I agree that that would be way too many options. I ended up ordering a 4 position switch from Amazon. It actually has 5 positions with the 0 (off) position. I can program in 4 speeds - 60 hz as the default off position - (no return signal from the switch) and three other frequencies using the VFD contact terminals 1, 2 and 4- probably 50, 40 and 30. There will be one unused switch position because the above will use all single VFD contacts.

We'll see if I got it right:)
Rick
 
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