[JayneV]

Most people run these from an ordinary household supply with no problems, there isn't really 2.5kw of power evaporating in the VFD.

Re the er11 / er20 - I'd go for the er20 for better tooling choice. Most router bits will be quite small, 1/2" / 12mm are the biggest I regularly use, but occasionally you might want to use a tapered tool to cut draft angles and useful sizes are often on 16mm shanks, so er25 would be good.

I can see the ER20 being a better choice as far as having a larger selection of tooling to pick from. ER25 is getting too big for what I want. I’m not sure any of the 2.2kW or smaller spindles come with an ER25 collet and the collet itself might start getting in the way of any deep cuts I’m likely to do. ER20 is the largest I would want for this machine.

[Zorbit]

ER20 will be fine for most things. Being able to use 12mm tools is good, and loads of old 1/2" tools turn up cheap.

[mactec54]

Yes, I have a 3ph meter in the meter box at home and adding a new 3ph circuit on its own breaker to the garage is possible. I’d have to get a quote from my electrician friend to see how much that will cost. I don’t expect it to be very cheap, because the meter is at the opposite end of the house to the garage so will means a long cable run. The cable alone will probably cost more than I’d like to spend, but I’ll ask for a quote anyway.

The phase converter I linked previously was meant only as an example. I forgot to factor in the higher output voltage, my apologies. Such a converter would be pointless for me anyway, since my house already has 415V 3Ph power available at the meter box.

I’m still not clear with how current and power are defined when asking about 3ph. So, using the 2.2kW spindle as an example, it is rated at 10A and 2.2kW, so do those numbers refer to each phase? In other words, does each of the three windings require 10A, or is the net current draw 10A with each winding drawing 10/1.732=5.77A? I’m a bit rusty with my 3ph theory.

You will not have a spindle that is 220v it will be 380v 3Phase the Amps will be lower for that spindle, and only draw a little more at the VFD Drive input for the 3Ph 400V supply you have, so this puts you in a very different place.

In terms of Amps per Phase.

Divide 2.2 kW by the power factor of 0.85 to get 2.6 kVA. Divide that by 3 to get 0.863 KVA per winding. Divide that by 415 volts to get 2.08 amperes per winding. If you are running star, then that is the phase current. If you are running delta which most will be , then multiply by the square root of 3 (1.732) to get 3.6 amperes per phase.

This is just a random power factor number, yours can be very different to this, and I think your 3 Phase voltage will be closer to 400v, ( You need to check it ) so these are just numbers which I don't like posting because everyone's system can be different. so is a meaningless exercise, but this shows you how to calculate the Amps per Phase if you have all the parameters to work with.

When you get the quote, this will be to a sub box in your shed / workshop, and that you will need ( 1 ) supply for your machine which will include 3 Ph and Single Phase so the cable will have to be suitable for this.

[mactec54]

Most people run these from an ordinary household supply with no problems, there isn't really 2.5kw of power evaporating in the VFD.

Most people do not.

You obvious have no clue at all, posting information like this, can give false hope for someone that is about to buy a spindle like this, that they can not run with the power supply they have (wedge),

You can not run a 2.2Kw 400Hz spindle, from a 15Amp Single Phase supply, those that do fail, the spindle will run but have no power /torque to cut with. and will trip the Breaker, with any loading applied to the motor. 1.5Kw spindle will run on a 20A circuit, it will also trip a 15A circuit Breaker.

[pippin88]

I don't know the Hz, but I run a 2.2kw spindle from a 240v 10amp supply fine.
(Well the breaker is actually a 16amp, but the socket is rated at 10amp, as is standard for normal sockets in Australia)

Cuts just fine.

I don't take 30mm deep cuts with a 12mm cutter at a million metres per minute and I'm sure am not loading the spindle anywhere near capacity.

[JayneV]

There is no false hope. I won’t be purchasing any spindle until I completely understand the specs of the spindle/VFD. I’m just asking some additional questions along the way because I haven’t had anything to do with 3ph power theory since my days at school a long time ago and those brain cells need some refreshing.

Out of interest, what type of circuit do people usually have in North America for running one of these Chinese 2.2kW spindles with a single phase supply? And if there is anyone from Aus/NZ that has one of these spindles, what type of circuit do you have?

EDIT: Is it possible to derate the VFD/Spindle to limit the output power so I can use my currently available power supply? If that is possible, I could buy the 2.2kW Spindle and use it at a lower power setting until I can upgrade the power circuit at a later time. I’m expecting a new circuit (wiring, circuit breaker, labour costs, etc, won’t need a sub board because the garage is attached to the house) will be too expensive to upgrade with my currently available budget allocates to the CNC. It would be a bonus if I can buy the larger spindle first time round without needing to buy a smaller one and upgrade later.

[JayneV]

I don't know the Hz, but I run a 2.2kw spindle from a 240v 10amp supply fine.
(Well the breaker is actually a 16amp, but the socket is rated at 10amp, as is standard for normal sockets in Australia)

Cuts just fine.

I don't take 30mm deep cuts with a 12mm cutter at a million metres per minute and I'm sure am not loading the spindle anywhere near capacity.

That’s good to know pippin. Thanks.

Regarding your breaker, that would be rated to match the wiring. It’s probably larger wire on that outlet than your regular 10A outlets. There is a formula for calculating the wire size depending on how many outlets are on the same circuit and their rating but I don’t recall what the formula is. It’s all listed in the AS/NZ Wiring Standards if you are bored and looking for something to do. lol. Your supply is capable of 16A on that circuit, shared between all the outlets on that circuit. I’d have to double check, but I’m pretty sure my 15A outlet has a 20A circuit breaker at the meter box. The difference between a 10A and 15A outlet is the size of the contacts inside. The 15A will have larger contacts, actually, it’s just the earth contact that is larger, the active and neutral are the same size as a 10A outlet.

[mactec54]

There is no false hope. I won’t be purchasing any spindle until I completely understand the specs of the spindle/VFD. I’m just asking some additional questions along the way because I haven’t had anything to do with 3ph power theory since my days at school a long time ago and those brain cells need some refreshing.

Out of interest, what type of circuit do people usually have in North America for running one of these Chinese 2.2kW spindles with a single phase supply? And if there is anyone from Aus/NZ that has one of these spindles, what type of circuit do you have?

EDIT: Is it possible to derate the VFD/Spindle to limit the output power so I can use my currently available power supply? If that is possible, I could buy the 2.2kW Spindle and use it at a lower power setting until I can upgrade the power circuit at a later time. I’m expecting a new circuit (wiring, circuit breaker, labour costs, etc, won’t need a sub board because the garage is attached to the house) will be too expensive to upgrade with my currently available budget allocates to the CNC. It would be a bonus if I can buy the larger spindle first time round without needing to buy a smaller one and upgrade later.

Buy the 1.5Kw spindle then, as this will just scrap by on 15A circuit, if loaded this will also trip the Breaker, but will run up to full power.

There is a mix in NA of some 120v users and 240v users, Most though in NA would have a 240v circuit from 25A to 50A for there complete machine, when using single phase supply, just as the VFD Drive manufacturer's recommend.

20A is standard in NA for a normal outlet, and is easy to have a 30A /40A circuit for the Garage, anyone that installs a new 240v circuit in NA would do a 25A / 30A circuit minimum the extra cost of wire Breaker and plugs is not much at all.

Derating is not advisable but a some do it, you just use a lower max Amp Parameter setting, by doing this you have a wimpy spindle and will stall easy.

If you were to upgrade your power to 3Ph then you would have to buy a new spindle and VFD Drive that would have 380v /400v rating to match the 3Phase power supply, and have to rewire some of your cabinet.

[mactec54]

I don't know the Hz, but I run a 2.2kw spindle from a 240v 10amp supply fine.
(Well the breaker is actually a 16amp, but the socket is rated at 10amp, as is standard for normal sockets in Australia)

Cuts just fine.

I don't take 30mm deep cuts with a 12mm cutter at a million metres per minute and I'm sure am not loading the spindle anywhere near capacity.

What do you have the Amps Parameter set to in the VFD Drive for your spindle ???

[mactec54]

That’s good to know pippin. Thanks.

Regarding your breaker, that would be rated to match the wiring. It’s probably larger wire on that outlet than your regular 10A outlets. There is a formula for calculating the wire size depending on how many outlets are on the same circuit and their rating but I don’t recall what the formula is. It’s all listed in the AS/NZ Wiring Standards if you are bored and looking for something to do. lol. Your supply is capable of 16A on that circuit, shared between all the outlets on that circuit. I’d have to double check, but I’m pretty sure my 15A outlet has a 20A circuit breaker at the meter box. The difference between a 10A and 15A outlet is the size of the contacts inside. The 15A will have larger contacts, actually, it’s just the earth contact that is larger, the active and neutral are the same size as a 10A outlet.

Here is the circuit requirement's from a Hitachi VFD Drive install, this is one of the many manufacturer's that have the requirement's listed in there manuals, so it is easy to see what is required. I could post many of these from the VFD Drive manufactures, and they will all say the same.

This is an Electrical code requirement, no matter how you try to do this the end result will have to be the same, to comply.

[Zorbit]

Buy the 1.5Kw spindle then, as this will just scrap by on 15A circuit, if loaded this will also trip the Breaker, but will run up to full power.

What planet do you live on ? Electricity must be different there.

[Zorbit]

JayneV, here is a thread from the UK covering the same spindles, with comments from JazzCNC who has built and sold many, many machines with them.

Connecting 2.2kw vfd to Mains supply - Page 2 (mycncuk.com)

In particular note where he writes;

"Andrew I haven't personally used the Hitachi but I built a machine for some one who uses the same VFD with same spindle and it's perfectly fine. Infact the whole machine including VFD runs from 13A socket run down to shed via electrical extension cord. This was 5yrs ago and still hasn't burnt the shed down so can safely say it's ok.!!

Also My ABB 2.2Kw VFD is rated 25A and still it's fine run from 13A. I fit lots of these 2.2Kw Spindle VFD setups and I haven't had one that taxs 13A so sleep safe.!"

[JayneV]

Hi Zorbit,

I came across that CNCUK thread yesterday, thank you anyway. From the little information I have been able to find online, I believe the reason the VFD manuals all have such a high input rating compared to the output is to cater for the startup current draw when the VFD is turned on until the capacitors charge, but that is just a guess. It’s the only explanation that makes any sense why the VFD would be rated at approx 5kW at the input (220V x 23A = 5060W) and only be able to drive a 2.2kW spindle.

I’m still searching for an answer why all the “2.2kW” VFD’s require so much input current, all the different manuals I’ve found have similar requirements. Obviously there is not 2.8kW being dissipated by the VFD otherwise it would be glowing red hot so there has to be a logical explanation. I also want to point out that I’m not trying to reinvent what the VFD designers have come up with, I’m just trying to understand how it all works. I’m still very confused.

[mactec54]

JayneV, here is a thread from the UK covering the same spindles, with comments from JazzCNC who has built and sold many, many machines with them.

Connecting 2.2kw vfd to Mains supply - Page 2 (mycncuk.com)

In particular note where he writes;

"Andrew I haven't personally used the Hitachi but I built a machine for some one who uses the same VFD with same spindle and it's perfectly fine. Infact the whole machine including VFD runs from 13A socket run down to shed via electrical extension cord. This was 5yrs ago and still hasn't burnt the shed down so can safely say it's ok.!!

Also My ABB 2.2Kw VFD is rated 25A and still it's fine run from 13A. I fit lots of these 2.2Kw Spindle VFD setups and I haven't had one that taxs 13A so sleep safe.!"

You obvious have no electrical knowledge, simple high school math will tell you that a 13A Single Phase supply to the VFD input, will not give you a 3Phase 10A output, which is needed to have the full Power for the 2.2Kw spindle motor, remember simple math.

Low power supply means low performance, as I said these spindles can run on a low amp power supply, but you are not getting a 2.2Kw performance, you can calculate what you are getting out of your spindle, by what your power supply current draw is, your connection of 13A will give you around a 1000Watts at best, that's a long way from 2.2Kw so stop dreaming, that you are running a 2.2Kw spindle on your power supply because you are not. Here is what your ABB VFD Drive manual says you require, I guess that you know better than the manufacture. if you think any different

A note if you are fitting these VFD Drive and using these connections this would be illegal wiring, so I hope if you are doing this for anyone that they know what you are doing is not to the electrical code requirement's, for an install like this.

[Zorbit]

You obvious have no electrical knowledge, simple high school math will tell you that a 13A Single Phase supply to the VFD input, will not give you a 3Phase 10A output, which is needed to have the full Power for the 2.2Kw spindle motor, remember simple math.

Low power supply means low performance, as I said these spindles can run on a low amp power supply, but you are not getting a 2.2Kw performance, you can calculate what you are getting out of your spindle, by what your power supply current draw is, your connection of 13A will give you around a 1000Watts at best, that's a long way from 2.2Kw so stop dreaming, that you are running a 2.2Kw spindle on your power supply because you are not. Here is what your ABB VFD Drive manual says you require, I guess that you know better than the manufacture. if you think any different

A note if you are fitting these VFD Drive and using these connections this would be illegal wiring, so I hope if you are doing this for anyone that they know what you are doing is not to the electrical code requirement's, for an install like this.

You are confused. BTW I am a qualified electrician and ran my electronics repair company for 15 years, mostly repairing switched-mode power supplies, but don't take my word for it - just look and see what other people are doing.

[Zorbit]

I believe the reason the VFD manuals all have such a high input rating compared to the output is to cater for the startup current draw when the VFD is turned on until the capacitors charge, but that is just a guess.

It's a good guess. Inrush current can be very high on older designs. Quality circuits incorporate limiting devices such as NTC ( resistors that start at a high value which rapidly drops when they get warm ), resistors that charge the caps slowly then a circuit or relay shorts those resistors when the caps are charged, or zero-point circuits that connect the caps when the mains voltage is at the 0v crossover point to avoid massive inrush. Sometimes you can hear a ping when the caps are charged and a relay clicks in. Modern PWM designs handle it much better.

[JayneV]

At the risk of opening Pandora’s Box I’m going to present some calculations for (respectful!!!) comments because I am confused as hell! The example I will present will use the figures from the attachment. I will assume a 220V single phase supply and will also assume 100% efficiency in the VFD and a power factor if 1 to keep things simple.

Rated Output: 2.2kW
Input: 220V single phase
Output: 220V 3 phase
Rated Input Current: 23A
Rated Output Current: 10A
Power Factor(PF): 1

At the input:
Input Watts: W = V x I = 220 x 23 = 5060W = 5.06kW

Output Watts: W = V x I x PF x 1.732
2200 = 220 x I x 1 x 1.732
Solving for I: I = 2200 / (220 x 1 x 1.732) = 5.77A (per phase??)
5.77 x 1.732 = 10A (3 phase current)

Output using a PF of 0.85:
2200 = 220 x I x 0.85 x 1.732
I = 2200 / (220 x 0.85 x 1.732) = 6.79A

The numbers are not adding up.

Looking at it differently, a Watt is a measure of energy. 1W= 1 joule per second. It shouldn’t matter if the energy is created by single phase or 3 phase electricity or even a GE CF6 jet engine burning jet fuel, energy is energy. So for a VFD that has an efficiency greater than 90%, it should not take more than 5kW to output 2.2kW.
At 90% efficiency, 2.45kW x 90% = 2.2kW. So for a 220V supply, 2450W/220V = 11.14A. So why does the VFD require a 13A supply?

I keep trying and can’t make the numbers add up, there has to be a reason why all the manufacturers list the input current so high. It’s not being consumed by the spindle and it’s not being dissipated as heat so where is it being used?

I hope someone can explain this to me in simple terms because it’s driving me crazy.

My brain has now exploded and I need to take a nap.

[JayneV]

It's a good guess. Inrush current can be very high. Quality circuits incorporate limiting devices such as NTC ( resistors that start at a high value which rapidly drops when they get warm ), resistors that charge the caps slowly then a circuit or relay shorts those resistors when the caps are charged, or zero-point circuits that connect the caps when the mains voltage is at the 0v crossover point to avoid massive inrush. Sometimes you can hear a ping when the caps are charged and a relay clicks in.

Would the inrush current for VFD be greatly different from the starting current of a normal AC single phase motor? If my memory is correct, the starting current if a motor is usually assumed to be 6x it’s normal operating current. Motors run all day long, starting and stopping, Luke the fridge, air compressors, air conditioners, etc.

[Zorbit]

Would the inrush current for VFD be greatly different from the starting current of a normal AC single phase motor? If my memory is correct, the starting current if a motor is usually assumed to be 6x it’s normal operating current. Motors run all day long, starting and stopping, Luke the fridge, air compressors, air conditioners, etc.

I've edited my post to reflect that modern PWM circuits handle inrush much better than older circuits, and I just looked it up, it can be 100 - 150% of full motor current. I think your approach of comparing power rather than amps is the right one. A 13 amp UK outlet can easily supply 2.2Kw, and many people run 2.2Kw spindles perfectly well from that supply. It works well, as proven by many happy users. Your choice though.

ABB say "It is also important to note that current is limited on the application of input power by the design of the drive's pre-charge circuit. The dc bus capacitors are soft charged based on an RC time constant such that the current at power up will be well below the motor's FLA"

[Zorbit]

This might go some way to explaining the ridiculous input current numbers:

"That's a phenomenon that you only see pretty much in Japanese drives like Yaskawa, Mitsubishi etc, and is more of a marketing and UL listing issue believe it or not. Japanese drives are primarily designed for their market, where they have to contend with motors being designed slightly different than the rest of the world, because they have an even worse situation that we in the US do with regard to different power distribution systems. Some parts of the country are 50Hz, some are 60Hz, and the 3 phase voltage levels are odd too. In the 50Hz sections, they use 200 and 400V, in the 60Hz sections they use 220, 400 and 440V. So their motors, to be compatible everywhere in Japan, have to be designed to accept all of the different V/Hz ratios those represent. That then means when they design their VFDs, they are designing them for THEIR motors, and adapting the MARKETING of those designs to be used in the rest of the world.

Then when they send that drive to the US and have to get it UL listed for a particular HP, the HP rating has to correspond to OUR motors, which has to do with the OUTPUT ratings, but the Input ratings have to do with the MAXIMUM input current (per UL rules) without being tied to what is connected to the Output side. So in reality if, picking from the first column on your chart, the input amps are shown as being rated at 44A while the output current is shown as being rated for 38A. That's because it is being sold here as a 25HP 460V drive, which needs to be capable of 34A for that motor. But the drive was DESIGNED by Yaskawa for a different motor in Japan, which would require more output current and take 44A input current. When they took it to UL, the INPUT current is still the same, but because UL insists on this disambiguation of input and output ratings, the 44A input current is still shown. When you actually run that 25HP motor at full load of 34A, the input current will be LESS than 34A.

I know, it's confusing. I had to have a Yaskawa engineer explain it to me once. But you can sum it up as a glitch in how UL requires that VFDs be listed. The 44A is just what UL insists it be listed at, mostly because of the NEC rule on conductor sizing feeding the VFD being based on the VFD maximum input current, not the motor size."

VFD Input current | Mike Holt's Forum