[Odinsbeard]

Good morning everyone, i recently purchased a cnc kit that includes a 2.2kw 110v vfd as well as a 2.2kw 110v spindle. Now, im not an expert, but the spindle manual states it can only take 8 amps. By my calculation thats only 880watts of power. Am I missing something here? How is the 2.2kw power rating arrived at? I know the output of the vfd is 3phase. Is it not as simple as saying 110v *8a = 880watts? Does each leg of the 3phase carry close to 8 amps? Any advice would be appreciated.

[mactec54]

Good morning everyone, i recently purchased a cnc kit that includes a 2.2kw 110v vfd as well as a 2.2kw 110v spindle. Now, im not an expert, but the spindle manual states it can only take 8 amps. By my calculation thats only 880watts of power. Am I missing something here? How is the 2.2kw power rating arrived at? I know the output of the vfd is 3phase. Is it not as simple as saying 110v *8a = 880watts? Does each leg of the 3phase carry close to 8 amps? Any advice would be appreciated.

No you are not missing anything that is correct and they are junk the max you can use on 120v NA supply is 1.5Kw

[Odinsbeard]

No you are not missing anything that is correct and they are junk the max you can use on 120v NA supply is 1.5Kw

Better not tell the wife then... quick question how are you arriving at 1.5kw.

[BBMNet]

Hello.

I mostly agree with mactec54 except for one thing. The actual power would be somewhat lower than those 1.5KW due to the power factor.

Assuming a PF equal to 0.85, the equation to calculate that is

P = SQR(3) V I PF = 1.73 x 110 x 8 x 0.85 = 1,219 KW

To accomplish your given 2.2KW a current of about 14 amps would be required.

It would be quite interesting to know how your supplier calculates those 2.2KW. Please post a picture of both the VFD and the motor plates. The brand of the equipment could also help.

It might be possible that the VFD can deliver the aforementioned 14 amps. I can´t tell if the motor can withstand that current. Most probably not.

I must say that I´m very intrigued by those specs.

Regards.

[mactec54]

Better not tell the wife then... quick question how are you arriving at 1.5kw.

You need at least 20A 120v supply minimum to run a 1.5Kw a 25A is better and the normal requirement to be safe for the 1.5Kw spindle, most 120v single phase supplies is on a15A Breaker

Check your single phase Power and see what you have 20A Breaker and you can run the 1.5Kw but not the 2.2Kw you will trip the Breaker the first time it loads up

[mactec54]

Hello.

I mostly agree with mactec54 except for one thing. The actual power would be somewhat lower than those 1.5KW due to the power factor.

Assuming a PF equal to 0.85, the equation to calculate that is

P = SQR(3) V I PF = 1.73 x 110 x 8 x 0.85 = 1,219 KW

To accomplish your given 2.2KW a current of about 14 amps would be required.

It would be quite interesting to know how your supplier calculates those 2.2KW. Please post a picture of both the VFD and the motor plates. The brand of the equipment could also help.

It might be possible that the VFD can deliver the aforementioned 14 amps. I can´t tell if the motor can withstand that current. Most probably not.

I must say that I´m very intrigued by those specs.

Regards.

That is incorrect when using a VFD Drive on single phase 120v / 240v the input current is double the output current, so 14A at the spindle and 28A on the input supply to the VFD Drive which you would have to run a 30A 120v circuit to run it, on 240V the required Breaker for a 2.2Kw spindle is 30A this is in most VFD Drive spec's

[mactec54]

Hello.

I mostly agree with mactec54 except for one thing. The actual power would be somewhat lower than those 1.5KW due to the power factor.

Assuming a PF equal to 0.85, the equation to calculate that is

P = SQR(3) V I PF = 1.73 x 110 x 8 x 0.85 = 1,219 KW

To accomplish your given 2.2KW a current of about 14 amps would be required.

It would be quite interesting to know how your supplier calculates those 2.2KW. Please post a picture of both the VFD and the motor plates. The brand of the equipment could also help.

It might be possible that the VFD can deliver the aforementioned 14 amps. I can´t tell if the motor can withstand that current. Most probably not.

I must say that I´m very intrigued by those specs.

Regards.

This is the requirement for any VFD Drive note that this is for 220v /240v you will have to double this for 120v supply

[ihavenofish]

Hello.

I mostly agree with mactec54 except for one thing. The actual power would be somewhat lower than those 1.5KW due to the power factor.

Assuming a PF equal to 0.85, the equation to calculate that is

P = SQR(3) V I PF = 1.73 x 110 x 8 x 0.85 = 1,219 KW

To accomplish your given 2.2KW a current of about 14 amps would be required.

It would be quite interesting to know how your supplier calculates those 2.2KW. Please post a picture of both the VFD and the motor plates. The brand of the equipment could also help.

It might be possible that the VFD can deliver the aforementioned 14 amps. I can´t tell if the motor can withstand that current. Most probably not.

I must say that I´m very intrigued by those specs.

Regards.

His point was that we are restricted to 15 or 20 amp fuses on 110v single phase, which generally restricts you to a 750w true continuous output spindle.

Anything else is like the old "3hp hand router" trick, only to realise that rating is the draw just before it catches fire, and not vaguely related to the actual output performance when it starts tripping breakers cutting balsa wood.

So, the short end of this is, no, you don't have a 2.2kw spindle running on 110v, no matter how its labelled.

Teknomotor rates their spindle on output performance. For example, a teknomotor 730w 3 phase 220v spindle on a delta MS300 750w 110v drive will give you a continuous 750w cutting load drawing 3.6 amps at the spindle. The drive can handle 5.5A at the spindle, drawing 20.6 amps at the 110v outlet. So, as you can see you can get 150% load, for as long as your motor can handle it (in the tekno's case, about a minute) and you'll get some peaks above that for fractions of seconds, before the breaker blows, or drive complains. If you tried to run an 1100w spindle, you would have zero overload capability, and would trip the breaker constantly.

This is why you'll never seen any vfd or servo drive above 750w that is meant to run on 110v single phase form a source that is truthful (delta, yaskawa, hitachi, etc). You only see them from sketchy sellers trying to fulfill your dreams of a 2.2kw spindle - by basically putting a new sticker on a 750w version.