220 volt three phase element

Thread Starter

Brandyne

Joined Aug 30, 2022
5
I have a 3 phase element for a steam generator but the element is a 220 volt element. the diagram is in Chinese which i cant read. on the diagram it shows three phase delta connection for 380v and three phase star connection for 220 volt with a neutral connected to the star point. My question is can I connect the three phase as is to the element meaning there will be 230v phase to neutral and 400 phase to phase or does the voltage need to be stepped down to 110 volt phase to neutral and 230 volt phase to phase ?

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MisterBill2

Joined Jan 23, 2018
13,194
You have not mentioned the supply voltage that you want to connect, that makes a big difference.
Also note that the motor and all of the control circuit is powered by the phase "A" to neutral voltage. Star connected heaters do not usually require the neutral connection to the center.
If the elements are intended for 220 volts then the delta connection may be OK.
 

Thread Starter

Brandyne

Joined Aug 30, 2022
5
You have not mentioned the supply voltage that you want to connect, that makes a big difference.
Also note that the motor and all of the control circuit is powered by the phase "A" to neutral voltage. Star connected heaters do not usually require the neutral connection to the center.
If the elements are intended for 220 volts then the delta connection may be OK.
Thanks for your reply. the supply voltage I have is 400V phase to phase/230V phase to neutral. the machine has a 220v three phase element which calls for the star with neutral on the diagram. My understanding is that connecting the 400V supply with neutral on the star point will effectively give the 230V needed on each winding of the elements. But im not 100% sure on this
 

Thread Starter

Brandyne

Joined Aug 30, 2022
5
OK, and for a system with 220 volt heaters. you will need to change the connection to star.
Ok thank you. So I can just connect the 400V phase to phase supply to the elements and connect the neutral to the star point and it will work ok with 230V on each element?
 

MisterBill2

Joined Jan 23, 2018
13,194
For our 440/480 volt power the voltage between each phase and neutral is 277 volts.
So really you need to measure the actual voltage from each phase to the neutral. AND yu need to be able to verify that the othercomponents can perform correctly with the higher voltage . Understand that all of the controls and the motor are fed by the voltage between phase "A" and common..
400 volts is not a common voltage in my area, that level is often 480 volts between phases and 277 each phase to neutral. So you may need to use a step down transformer to power the controls and the motor.
So measure the voltage first. What part of the worlld are you located in?
 

Thread Starter

Brandyne

Joined Aug 30, 2022
5
For our 440/480 volt power the voltage between each phase and neutral is 277 volts.
So really you need to measure the actual voltage from each phase to the neutral. AND yu need to be able to verify that the othercomponents can perform correctly with the higher voltage . Understand that all of the controls and the motor are fed by the voltage between phase "A" and common..
400 volts is not a common voltage in my area, that level is often 480 volts between phases and 277 each phase to neutral. So you may need to use a step down transformer to power the controls and the motor.
So measure the voltage first. What part of the worlld are you located in?
Im in South Africa. our supply used to be 380 V phase to phase and 220V phase to neutral but some years ago they stepped it up to 400V and 230V but it varies between 380 and 400 as our electrical supply is in shambles here.
 

MaxHeadRoom

Joined Jul 18, 2013
26,003
Star point (coil voltage) = Phase to phase voltage / √3.
Neutral point current will be zero for a balanced 3ph load.
 
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MisterBill2

Joined Jan 23, 2018
13,194
OK, with 400 volts phase to phase the heater elements must be rewired to the star configuration shown, ot they will receive much more than their design voltage. With the star connection the voltage across each heater will be 230 volts, which is close enought to 220 volts to be withing nirmal tolerance limits.
AND the neutral must be connected because the rest of the system is powered between phase "A" and neutral.
 

MaxHeadRoom

Joined Jul 18, 2013
26,003
The 1ph circuit is totally different to the 3ph, in which 3 Delta connected loads are 3ph fed., If connecting 3 lower voltage star connected loads of equal power then they would be connected in Star configuration with no requirement for neutral.
The 1ph is there to control the 3ph contactors.
 

Janis59

Joined Aug 21, 2017
1,491
By definition there are in three phase standard 380/220 V network that between any of phases stay 380V whilst between any of phases to the ground (Earth, nul) stays 220 V. Therefore if You switch Your heaters in Y circuit, everything works well.
 

MisterBill2

Joined Jan 23, 2018
13,194
The 1ph circuit is totally different to the 3ph, in which 3 Delta connected loads are 3ph fed., If connecting 3 lower voltage star connected loads of equal power then they would be connected in Star configuration with no requirement for neutral.
The 1ph is there to control the 3ph contactors.
The circuit shown in post #1 tells us that there is One power feed, and that phase "A" is tapped off after the main disconnect switch. Hence my assertions avoided having to modify the equipment other than the provided heater connection changes.
 

MaxHeadRoom

Joined Jul 18, 2013
26,003
The bottom line is that the design itself does not conform to N.A. or EU customary standards as far as the control circuit is concerned, and is typical of equipment coming out of China.
 

MisterBill2

Joined Jan 23, 2018
13,194
My understanding of geography is that Southern Africa is not located either in the US, Canada, nor in Europe.
As a result the rules, regulations, and many equipment standards are not the same.
 

shortbus

Joined Sep 30, 2009
9,649
My understanding of geography is that Southern Africa is not located either in the US, Canada, nor in Europe.
As a result the rules, regulations, and many equipment standards are not the same.
So then you think they make items/machines to conform to each county's requirements? Instead of the rest of the world at large?
 

MaxHeadRoom

Joined Jul 18, 2013
26,003
My understanding of geography is that Southern Africa is not located either in the US, Canada, nor in Europe.
As a result the rules, regulations, and many equipment standards are not the same.
I understand that the RSA could be in a bit of a turmoil as far as regulations, but IMO it is no excuse for China to adopt bad practices when it comes to electrical equipment, especially if for export to the rest of the world.
I have first hand information from those that have imported to N.A. and they are just as bad.
In many cases the machinery came in without any ground circuit references included. :(
Incidentally I see no indication of any Earth GND reference in the OP's DWG?
 
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