Huanyang VFD - RPM is not reading correctly

I recently completed the install of a Vevor 220v 2.2kw Water cooled spindle. I’m using a Huanyang VFD. It all seems to be working correctly but when I switch the VFD readout from HZ to RPM, the Max RPM (corresponds to 400 Hz) is around 12k, not the 24K that I’m expecting. I changed the PD143 (num poles) setting from 4 (default) to 2, but I still get a max RPM of 12k. Is anyone familiar with this issue and how to resolve it?

Look in to the PD144 setting.

1 Like

BTW, your can pick up a digital tachometer for about $20US that will help you confirm the actual speed vs what the VFD is telling you. Good for piece of mind.

Hey Tim,

by using the search function of this forum and having searched for Huanyang RPM you would have found:


Also check PD settings for PD003,PD004,& PD005. They should all be set to 400htz. If not set them in reverse order starting with 5 then 4 then 3.

1 Like

Set PD144 to 3000 and now max RPM is reading 24000 as expected. Thanks.

1 Like

Thanks Charley. PD003, PD004, PD005 are all set to 400.

Question, how do I know what PD143 (num poles) should be set to. The default is 4. I have a cheap devour spindle and have no information to go on.

Check PD072 and PD144 also. Here is a reference point (need to be adjust for 220v)

Hey Tim,

  1. you can measure the currents the spindle produces if you turn it manually. Every induction motor is an induction generator. You can connect a multimeter which is set to 200 V DC between two of the three phase pins and turn the spindle manually. If you get one positive and one negative pulse value per turn, it has two poles. With four poles, you would get double the number of positive and negative pulses per turn. Here you see a diagram of a three-phase induction motor, at left with two magnetic poles and at right with four magnetic poles:
  1. You can deduce it from rated rpm and frequency. If your seller tells you it is rated 24,000 rpm at 400 Hz, you can calculate the number of magnetic poles back:

    The rotational speed of a spindle is calculated this way:


    e.g. 400 Hertz × 2 × 60 seconds / 2 poles = 24,000 rpm
    or:   400 Hertz × 2 × 60 seconds / 4 poles = 12,000 rpm

    This means with a spindle with two magnetic poles a VFD will make the spindle run with 24,000 RPM spindle speed at 400 Hz. If it was a spindle with four magnetic poles, at 400 Hz, it would run at 12,000 Hz according to the formula. To bring this spindle to 24,000 rpm, you would need 800 Hz.

So if you know how fast a spindle runs at a specific frequency (e.g. 24,000 rpm at 400 Hz), you do:

400*2*60/24000 = 2 poles

  1. You can deduce it from price. Spindles with four poles are more expensive, e.g.
1 Like