Confused on what potentiometer I should use on Delta VFD

[Rata222]

Hi. I purchased a Delta M series VFD (2HP) and want to hook up a remote potentiometer. The manual does not specify any specs for the potentiometer itself, but the specs for the AVI terminal say:

Impedance: 20k Ohm
Resolution: 10 bits
Range: 0~10Vdc = 0~Max.Output Frequency

On YouTube -one video shows using a 5K Ohm for this model, but in the comments he says use a 1 K Ohm. Another forum answer said 2.5 K Ohm. Can I determine what is correct from the Delta listed specifications? Is the 20 K ohm shown in the specs a maximum value allowed for that connection? Or does that indicate a 20K Ohm pot?

Thank you for any help.

 

[markba633csi]

Either 5k or 2K pots should work fine. You want a pot resistance somewhere between 5 to 10 times lower than the input impedance of the VFD input port. Make sure it's a linear taper pot, not a volume control type pot which is log taper (non-linear). Using shielded cable for the pot is often a good idea if the pot must be mounted far away from the VFD.

The downside of using a pot that's too high a resistance would be that the pot circuit would be more susceptable to EMI interference from the motor wiring, especially if the pot wiring is long like more than 4 feet or so and not shielded. Keep the pot wiring away from the motor wiring and power wiring.
The downside of too small a pot value is possibly loading down the pot supply voltage from the VFD, but you'd probably have to go below 500 ohms to do that. Depends on how much current in milliamp the VFD pot port can supply.

Putting a small capacitor from the pot wiper pin to the grounded pin can help prevent noise issues. Something like 0.1 microfarad at 50 volts ceramic disc or mylar cap (non-polarized type)

 

[mksj]

Per above. Manual specifies 3-5K, but 2-5K is fine and will make no difference, also important to specify linear tracking (not log/audio taper) potentiometer. Do not buy a cheap carbon type, as the contact can go quickly and or bounce with machine vibration. I recommend a film (conductive plastic or similar) or wire wound type, anything from 1/2-2W works fine as the current is a few mA. I do recommend shielded cable, usually 3 wire 20 or 22AWG, the shield is only connected at the VFD ground end, tape over or use shrink tubing at the other end. If running parallel to the motor cable try to keep it 4-6" away or more. Some VFD's also have the ability to noise filter the speed cable input, but not this model.

Ohmite CU5021 Panel Mount 5k Ω (5000 ohms), 2W Potentiometer RV4NAYSD502A | eBay

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CLAROSTAT RV4NAYSD502A, Potentiometer, New In Box 5k Ohm 53C3-5000-S | eBay

<p dir="ltr" style="margin-top:0; margin-bottom:0;">This Clarostat potentiometer, model RV4NAYSD502A, is a top-quality electronic component that is sure to meet your needs. It comes in its original box and has never been opened, making it an excellent choice for anyone seeking a reliable and...

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RV4 Series 5K Ohm 2 Watt Industrial Potentiometer | eBay

25,000 cycle rotational life. Welding and heating. Electric vehicles. Linearity: ±5%.

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[Rata222]

Per above. Manual specifies 3-5K, but 2-5K is fine and will make no difference, also important to specify linear tracking (not log/audio taper) potentiometer. Do not buy a cheap carbon type, as the contact can go quickly and or bounce with machine vibration. I recommend a film (conductive plastic or similar) or wire wound type, anything from 1/2-2W works fine as the current is a few mA. I do recommend shielded cable, usually 3 wire 20 or 22AWG, the shield is only connected at the VFD ground end, tape over or use shrink tubing at the other end. If running parallel to the motor cable try to keep it 4-6" away or more. Some VFD's also have the ability to noise filter the speed cable input, but not this model.

Per above. Manual specifies 3-5K, but 2-5K is fine and will make no difference, also important to specify linear tracking (not log/audio taper) potentiometer. Do not buy a cheap carbon type, as the contact can go quickly and or bounce with machine vibration. I recommend a film (conductive plastic or similar) or wire wound type, anything from 1/2-2W works fine as the current is a few mA. I do recommend shielded cable, usually 3 wire 20 or 22AWG, the shield is only connected at the VFD ground end, tape over or use shrink tubing at the other end. If running parallel to the motor cable try to keep it 4-6" away or more. Some VFD's also have the ability to noise filter the speed cable input, but not this model.

markba633csi, mksj Thank you so much for the quick and detailed replies. Great information- I will use use it and hang on to it - I gained knowledge I will be able to use in the future.
mksj I appreciate you taking the time to provide me the links. May I ask - Where did you find the manual that had the pot call out? That diagram is not in my manual.
Helpful guys like you are what makes this a great forum. Thank you!

 

[mksj]

VFD user's Manual I pulled off the web, P2-2. I usually do a search for the model/series and add "PDF", there may be different versions of both the manual and VFD programming. Almost every VFD model I have come across use between a 2-5K pot, a few specify 1K or 2K. The most common would be 2K or 5K, if I have a very wide speed range say from 20-200 Hz then I opt for a 3 turn speed pot, and factory VFD installs sometimes use 10 turn. Usually the mil-spec. potentiometer are built to better specifications for vibration, moisture, life-cycle, etc. so I use them in VFD systems builds. The one I often install are rated at more than a million rotation cycles. Just examples below, but I would stick with one in the previous links.

ETI MW22B-3-5K this is a 3 turn pot.

https://www.mouser.com/ProductDetail/ETI-Systems/MW22B-3-5K?qs=wuXwK9wHm9tn2V5CTGq5Cw%3D%3D

ETI SP22E-2K single turn

https://www.mouser.com/ProductDetail/ETI-Systems/SP22E-2K?qs=wuXwK9wHm9tJD5TtBzWetA%3D%3D

 

[Rata222]

Thank you again. I will definitely go with one of those you send me, because I don't know how to tell anything about them. And thank you for the manual- Jim