Split phase on industrial devices

[ELCouz]

Hi there,


I want to build a professional CNC router for my garage.


I want to use the residential split phase configuration for power to my VFD and industrial power supplies.


I cannot find any straight answer regarding connecting 240V 1ph (L/N/E input) apparatus to 120V/120V (L1/L2/E).


Can I feed the other line to neutral terminal?



I asked the same question to my EE at my job and his head exploded! He said don't do that... why?

How do you guys runs your CNC at home? (step up transformer?)


I'm trying in hope to have a clear answer

Thanks a lot!!!
Laurent

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[ger21]

What country are you in?

[ELCouz]

Canada... 60hz in fact the same as US regarding residential power.

120v - 0v (center tap) - 120v

[Al_The_Man]

Simple if using 240v feed to the VFD, no neutral is required.
Just come off of a dual breaker.
If only using 120v then you would need a 120v VFD, but i would recommend you use 240v
Use 120v for the rest of the control.
Al.

[ELCouz]

There is no neutral available (NEMA 6-15 receptacle). I don't mind supplying 240v to the power supplies (and all the cabinet).

Example:

Take my 24V meanwell power supply. There is a 240v switch but can you put two LINE on it? Clearly state LINE + NEUTRAL on the terminals.

[Al_The_Man]

That is for countries such as UK etc that have 240v and N, in N.A. if using 240, just wire L1 and L2 to the N&L no neutral required.
Ensure you have a ground.
Al.

[john-100]

if you have equipment designed for a 240V single phase supply like I have in the UK

you can connect it to your 240V split phase suppy

provided the equipment has a two pole on/off switch and both L1 & L2 has the correct fuse or MCB

just connect L1 to L , L2 to N and E to E


John

PS
with switch mode power supplies the single phase AC supply is rectified to produce about 340V DC which
is then converted to a high frequency AC so it can be stepped down using a small ferrite cored transformer ,
then rectified to produce the DC output

If I remember correctly

with 3 phase VFD drives for the spindle motor

you can connect a 240V supply to the 3 Phase supply terminals L1(R) and L3(T) do not connect to L2(S)
using a single phase supply instead of a 3 Phase will reduce the maximum power available to 60% ??? - will need to check the manual


PPS see ATX power supply circuit



the LRS-350-24 power suppy is simpler circuit with a single 24V DC output ( and no standby 5V circuit !)

[ELCouz]

Thanks guys for all your reply!

Everything make sense now!

PS: Grounding is not an option, everything will be star grounded in the cabinet.

[mactec54]

Thanks guys for all your reply!

Everything make sense now!

PS: Grounding is not an option, everything will be star grounded in the cabinet.

The Power supplies you have are not suitable for you to run them on 240v in Canada, for NA you use 120V ( 1 ) Hot Neutral and Ground, they can be run on 240v, in NA but the failed rate is quite high

For your VFD and depending on what VFD you have most use L1 to ( R ) and L2 to ( S ) for the 240 Volt connection that is ( 2 ) Hot and a Ground, that is all you connect for the input Power for the VFD

[Al_The_Man]

In many cases the 1ph connection for VFD can be arbitrary, any combination of R,S,T. as most have just a 3 phase rectifier on the input.
For e.g on the popular Huanyang I have used any combination and works OK.
There is only one that I have come across that required two particular inputs and that was a Mitsubishi, because the low voltage supply was fed off of two particular inputs, instead of created internally after the bridge.
Al.

[mactec54]

In many cases the 1ph connection for VFD can be arbitrary, any combination of R,S,T. as most have just a 3 phase rectifier on the input.
For e.g on the popular Huanyang I have used any combination and works OK.
There is only one that I have come across that required two particular inputs and that was a Mitsubishi, because the low voltage supply was fed off of two particular inputs, instead of created internally after the bridge.
Al.

Huanyang can run on any combination, but most sellers will say to use R and T for the single Phase connection, this has the best reliability than any other connection combination

Mitsubishi, is only one of many that you have to use a specified connection for the input power, Yaskawa, Bosch, Emerson, Delta, Teco, Nowforever, the list is endless, most of the quality VFD drives will use R and S connection only for input power connection

It also depends how the internal DC Bus is connected, as to what input connections are best to use

[Al_The_Man]

I DID SAY in MANY CASES, over the years I have used many of the main manufacturers and this is what I have personally found the case to be.
As a rule, if the manual does not specify otherwise it is safe to assume any 1ph connection will work.
If as is common the input is just to a 3ph rectifer, it does not matter.
In the case of the Huanyang, et-al. the low voltage supplies are derived and fed after the 3ph rectifier, as is seen at power off where the logic stays active for some seconds.
You appear to insist on this regardless as per the recent post where you responded to a poster that claimed it to be so for Powertran, when an email to the company contradicted it.!

[ger21]

Here' the message I got for the Huanyang I just bought.

Regarding the wire connection, please connect "R" and "T" (at the inverter) to the shingle phase power supply (actraully, connect "R" and "S" or "S" and "T" both are ok.) If you use it as three phase input, then please connect the three phase power supply to "R, S T". "U, V, W " connect to a motor.

I think that this means you can use any two?

[Al_The_Man]

Here' the message I got for the Huanyang I just bought.
I think that this means you can use any two?

A lot clearer than my Huanyang manual,
"The power source is put into through the RST terminal, output on the UVW terminals. 220v can connect wilfully two phase of R.S.T."
AL.

[mactec54]

Here' the message I got for the Huanyang I just bought.


I think that this means you can use any two?

That is correct you can use any 2 connections, the most reliable though has be R and T for this VFD with 240v NA supply

[Al_The_Man]

Detailed Technically based reason for the recommendation?

[Al_The_Man]

Here' the message I got for the Huanyang I just bought.

I think that this means you can use any two?

Just to put this to bed once and for all.
Opening up the Huanyang on the bench, the R,S,T terminals go direct to a 3phase rectifier, therefore there is exactly no electrical difference between ANY combination of 2 out off the 3.
Al.

[mactec54]

Detailed Technically based reason for the recommendation?

The hundreds of postings speak for themselves, when users have had trouble with these VFD Drives it is usually how they have been wired, when they have changed there wiring connections to R and T there problems are usually gone, some also run fine on R and S, there are so many copies of this VFD it's hard to know what is going on Technically, they are all using a 3 phase rectifier, it may be how the DC Bus is connected across the rectifier as this can make a difference as to which connections are used, this simple snip speaks for it's self, how these cheaper VFD drives are configured inside

This shows why R and T is a better Balanced connection

[mactec54]

Just to put this to bed once and for all.
Opening up the Huanyang on the bench, the R,S,T terminals go direct to a 3phase rectifier, therefore there is exactly no electrical difference between ANY combination of 2 out off the 3.
Al.

And don't all VFD connect the same way, with some taps for internal low volt supply, R, S, T to the 3 phase Rectifier is normal, it's how the rectifier has been used, configured after the input as to what is the best connection to use, it has very little to do with the first Rectifier stage

[ger21]

DMM recommends R & S for their Dyn4 servo drives.
The Huanyang manual says any two, but the seller recommended R & T first, but any should work.
So I guess their is some difference.