Spindle power settings

I think I have something setup wrong but don’t know what. Running an Amana #45525 surface bit at the Amana settings of .9" stopover, 110 in/min feed, 55 in/min plunge and spindle at 18000 on white oak slabs I milled I can only get about 1mm step-down. Any more than that it will bog down on the harder spots and stops the spindle from spinning.

It seems to me with a 1.5kw spindle rated at 8A on 110V (yes the 140-145 settings are correct) I should be able to go deeper than 1mm step-down. On the VFD I see .66A on the output when spinning in the air but the most I see before a bog down is a bit over 2A.

Am I correct in thinking it should increase to the limit setting of 7A as set in F142 on this H100 VFD?

Hi Dave - I have not installed my spindle yet, but I’ve cut much deeper with my Makita and 1mm. Sometimes on purpose, but usually not :wink:

@Aiph5u should be able to answer your question - he’s the resident spindle guru (among others like @charleyntexas) :slight_smile:


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I been thru the VFD settings but don’t see anything yet that springs out other than the rated motor current in F142

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Hey Dave,

the motor current setting in the VFD (here: F142) has to be set according to the rated spindle current in spindle manual or nameplate.

See → here for details (and also here).

You also need rated voltage and number of magnetic poles.

If you want to see more Ampères flowing you can do this test to drive your spindle to its limits :slight_smile:

this is the spindle limit that you may confidently exploit but whether this is good for the bit or the cut depends on what is appropriate for the result. What matters is the speed of the cutting edge and whether you have good chips (on wood milling, what matters is to evacuate heat, therefore rather high speeds, and it’s the chips that evacuate the heat), I would start with relying on bit manufacturer’s recommendations for the bit, and then try it out.

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That was my point, this is an Amana bit and I set according to Amana settings except for step-down which I can’t get more than 1mm depth of cut with a the recommended 80% stepover at 110 in/min feed at 18000rpm when the step-down could be up to .125in according to Amana.
I am well aware of the speeds and feeds its just I have no other reference point for this spindle. Has anyone been able to see anything above 2A on a cut thru hardwood?

I just went thru and wrote down EVERY setting from 0 to 200 on the VFD and compared to the manual. Everything looks good except for F008 which is set to 380 for maximum voltage. The rated power in F140 is 1.5, rated voltage in F141 is 110, the rated current in F142 is 8, and the number of poles in F143 is 2.

The auto torque compensation is set to 2% but from what I read that is only for low speed operation.

I’ll try your link.

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Hey Dave,

you say the spindle is stopped, does it stop without the VFD tripping with error?

Have you set F144 to 3000?

I am not familiar with the V70/H100 VFD settings.

The VFD pretends to be able to run in vector mode. Are you running in V/F mode or vector mode? (F012)

Yes, F144 = 3000, F012=1 for vector. Just ran again watching amp display on VFD, it started to bog down and spindle stopped at 2.6A on a .5mm cut depth.

I would think it should have been up above 6 before bogging down.

Hey Dave,

you say the spindle is stopped, does it stop without the VFD tripping with error?

Yes, no error, it stops, I hit the stop button and raise the z and it starts again.

Hey Dave,

that is not what I would expect from a VFD. If the motor is stopped, you should have the VFD tripping with an error code on display telling you why it was stopped.

I cannot say if you have a setting wrong, because I am not familiar with this VFD. A quick look through all settings in the manual gives me no idea how the behaviour could be explained.

If you have a 110 V VFD and a 110 V spindle, why have you set F008 to 380 V? It should be set to the spindle nameplate voltage rating.

If you have a 110 V VFD and a 110 V spindle, why have you set F008 to 380 V? It should be set to the spindle nameplate voltage rating.
I did not change that setting AFAIK it came that way but agree and will change to nameplate.


Hey Dave,

what got me wondering is that you said the maximum was a bit over 2 A.

As the apparent power on three-phase motors is calculated with P=U·I·√3, with 1.5 kW and 380 V you get 2.28 A. That would be the current for a 1.5 kW spindle if it was at 380 V. Just a thought because you said you entered the rated power of 1.5 kW into a setting in VFD (this is not an existing setting on my VFD, just voltage and current)

But anyway, a motor should not be stopped without the VFD realizing that is is an error condition.

I think you’re onto something! I should have done the math, let me change F008

Hey Dave,

will read your answer tomorrow as it’s 1:34 AM in Central Europe, got to sleep!

You’re the man! Changed F008=110 and set 1.1mm depth and went like butter at about 4+ Amps. Set it to 2.3mm and it stalled and went to 8.8 amps but didn’t trip. So now I have the opposite problem, probably should set F142=7

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Hey Dave,

I am glad that the hint helped you and it works now.

I didn’t see anything in your manual regarding allowable overload or rated modes (IEC 60034-1 Duty Cycles), but on my VFD, in constant torque (CT) / high duty (HD) mode, it tolerates an output current overload of 150% for 60 seconds.

Yes, I see that also in the protection settings, I was able to shut it down well before that time. How hard is it on the spindle to be stuck and not spinning for a few seconds? Is it better to lower to time and let the VFD trop?

And since the VFD is well capable of handling 8+amps I presume the protection settings are primarily set for the spindle.

Hey Dave,

yes, the output current setting is the protection for the spindle.

This is difficult to say as you would need to know what the effects of the overloading exactly are in practice. The problem that generally arises is the heat when the VFD tries to make the spindle run against the load and increases the current. It’s the current in the coils that make the heat, so the VFD has to be able to detect stalling and to control the current in all cases of overload (a current overload does not only occur on mechanical overload, but can also happen if you set a too fast acceleration).

For adjusting the overload in the VFD, you usually rely on what the spindle manufacturer says, e.g. in the manual of my spindle it says:

Risks of electricity

Ensure protection against overload and short circuits!

In case of an overload – e.g. by a mechanically blocked shaft – or a short circuit, it has to be ensured that the spindle supply power is shut down immediately once the current exceeds the nominal current of the motor spindle. Also in case of a phase loss or an asymmetrical load, the power has to be shut down immediately. This can be reached by using matching motor protection switches or the proper programming of the variable frequency drive (VFD). It must be ensured that the spindle will not start automatically again after the protection device has been triggered once. In case that these instructions are neglected, dangerous temperatures of the motor spindle might be a consequence what can cause defects of spindle or machine or even increase the risk of fire.

However in my VFD, the motor’s rated current setting is not a strict limit that to exceed will make the VFD stop the spindle, but instead it is used to calculate the time-based heating effect. The VFD has thermal overload protection that is designed to protect both the VFD and the motor from overheating due to excessive load (the protection is based on using correct current rating for the motor). The level of electronic thermal setting can be adjusted from 20% to 100% of VFD’s rated current. As my VFD is rated 11 A output current in constant torque (CT) mode, but my spindle is rated 8 A in S1 constant duty mode, so with this parameter I adjust this to the Full load Ampère nameplate rating. The thermal curve can also be fine-tuned by different parameters. You can select the HD vs. ND mode which are two different overcurrent settings, in the first by default it allows 200 % overcurrent for 3 seconds and 150 % for 60 seconds, but it can be adjusted, it is an overload restriction that prevents overcurrent by reducing the frequency which simply slows down the acceleration. You can also adjust the motor cooling rate by varying the ramp down duration with wich a thermal counter decrements when the output current is below the set level again. There is a separate over-current trip suppression option that alters the ramp of acceleration to prevent an overcurrent. Finally you can set the restart behaviour after a trip, so you can define automatic restarts after over-current trips.

So my spindle manual strictly says, when the current is exceeded, the spindle has to be stopped immediately, while the VFD is so smart that it allows controlled overload and even considers the time with which an overloaded spindle will cool down before it can be overloaded again.

I think the spindle manufacturer wants to prevent you to do anything that could harm the spindle while the VFD manufacturer wants you to be able to get the most performance out of it.

That sounds reasonable to me as a firmware engineer and you’re probably correct on the motives of each type of manufacture. I been thinking of upgrading to a 2.2kw 220V spindle and a better VFD like the Omron MX2 or Hitachi. It would be nice if I could replace the VFD first but from what I’ve seen a 220V VFD expects to connect to a 220V spindle.

Hey Dave,

I would use the spindle and the VFD now that you have it. I am glad to read that you achieved your project. Oak is hard and your bit diameter is gigantic.