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Discussion Starter · #1 ·
Hello guys! I hope you can help me here, in regards to motor wye-delta starter.

In the motor nameplate: 220 Vac Delta/380Vac Wye 3 phase.

In the electrical panel we have 380Vac 3 phase supply. Upon starting the motor will start in wye connection with 380Vac supply, and then after a few seconds it will shift to Delta connection and continues running on delta connection until the process is done. During in delta connection the supply voltage is 380Vac, but in the motor nameplate the delta connection required 220Vac. how come this possible?

Pls. help me explain this...

Thank you in advance...
 

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Bilge Rat
motors and controls.........
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This motor is most likely 6 lead, maybe 12. It is designed to be operated at either 220 or 380. It is not designed to be started on wye then run on ∆.

The theory behind this is that it was designed for use in an area where the utility has transformers that are 220 volts. If they are connected ∆, then you have 220 3ø. If they are connected wye, then you have 380 3ø.

The ∆ and wye on the nameplate are a reference to how the 6 (or 12) leads are connected.

∆ = L1-1-6-(7-12); L2-2-4-(8-10); L3-3-5-(9-11). This results in a ∆ connection and requires 220 volts.

Y = L1-1-(12); L2-2-(10); L3-3-(11); 4-7, 5-8, 6-9 spliced. This results in a wye connection and requires 380 volts.

Don't run the motor in ∆ at 380 volts.

Apparently, it runs in ∆ for a fairly short time, otherwise it would burn up.
 

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Discussion Starter · #5 ·
Thank you so much for all your replies.
i found another motor installations here in the plant it really meets the condition you stated, but for this one it really make me confuse.

I have already measured the actual supply voltage: during Y start i measured 380V, and in delta run still i measured 380V.

It is a 6 leads motor. 37Kw. 220v delta/380v Y. BRAND: siemens .
TYPE: 1LA2207-2AA91-ZUO1

How i wish i could attached the photo which i have taken, but i can't find the attachment option. But instead i found some link which exactly the same to what we have this issue.

Thank you once again...


 

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As others have said, you connect the motor wye if your supply is 380 and in delta if the supply is 220. Draw it out and work out the voltages across each of the 3 coils and for both delta and wye connections.
You cannot run this motor as a wye start delta run if the supply voltage system is 380. You could if the supply voltage is 220.
 

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That Siemens motor catalog number is sold as a dual voltage version, meaning it is intended to be used in areas where either voltage is available, but NOT for Star-Delta starting. If you wanted that, it is sold as a SINGLE voltage motor (different catalog number) and you then connect it to the Star-Delta starter. So bottom line you have the wrong motor. Your best bet, if that motor is too difficult to change, is to forget the Star-Delta starter (bad idea anyway) and just go buy a solid state soft starter and connect that motor in Star.
 

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That Siemens motor catalog number is sold as a dual voltage version, meaning it is intended to be used in areas where either voltage is available, but NOT for Star-Delta starting. If you wanted that, it is sold as a SINGLE voltage motor (different catalog number) and you then connect it to the Star-Delta starter. So bottom line you have the wrong motor. Your best bet, if that motor is too difficult to change, is to forget the Star-Delta starter (bad idea anyway) and just go buy a solid state soft starter and connect that motor in Star.
or better still just hook it up on a drive if you are not sure. the drive won't need the star Delta option.
hope you will state what the motor is being used for

Sent from my HUAWEI Y210-0100 using Tapatalk 2
 

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or better still just hook it up on a drive if you are not sure. the drive won't need the star Delta option.
hope you will state what the motor is being used for

Sent from my HUAWEI Y210-0100 using Tapatalk 2
At 37kW a soft starter is likely cheaper than a drive, but you make a good point. If there IS any potential benefit to varying the speed, the cost difference to upgrade to a VFD is likely not much so this might be your opportunity to take advantage of it. But then you need to consider all the other issues involved, because that is not an inverter duty motor.
 
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Discussion Starter · #13 ·
By the way the motor application is for RO feed pump. For now i maybe use this instead:
ATS01N272Q-soft starter for asynchronous motor - ATS01 -72 A - 400 V - 37 KW.

Thank you all for all your advice it's really a great help...
 

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At 37kW a soft starter is likely cheaper than a drive, but you make a good point. If there IS any potential benefit to varying the speed, the cost difference to upgrade to a VFD is likely not much so this might be your opportunity to take advantage of it. But then you need to consider all the other issues involved, because that is not an inverter duty motor.
quick questions here jraef.ok most general purpose motors can run on vfds right? now the motor name plate is no where written inverter type. so how will you distinguish the two

Sent from my HUAWEI Y210-0100 using Tapatalk 2
 

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quick questions here jraef.ok most general purpose motors can run on vfds right? now the motor name plate is no where written inverter type. so how will you distinguish the two

Sent from my HUAWEI Y210-0100 using Tapatalk 2
There is no standard stating that a manufacturer must put anything on a nameplate stating that a motor is suitable for inverter use, but any motor mfr that wants to capture that market segment would be foolish not to. So generally if it does not say it, it probably isn't. But you can always go to the mfr and ask.

That said, finding that level of information within the behemoth that is Siemens can be a daunting task. I know, I used to work there... :blink:
 

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There is no standard stating that a manufacturer must put anything on a nameplate stating that a motor is suitable for inverter use, but any motor mfr that wants to capture that market segment would be foolish not to. So generally if it does not say it, it probably isn't. But you can always go to the mfr and ask.

That said, finding that level of information within the behemoth that is Siemens can be a daunting task. I know, I used to work there... :blink:
ok thanks.the reason as to why am asking is because where I work we are undertaking massive energy saving projects and one of the things we are doing is making all motors run on drive most of our motors are induction motors.and we can run them on speeds less than the rated.so when you mention inverter type that kept me thinking because most general purpose motors can run with drives


Sent from my HUAWEI Y210-0100 using Tapatalk 2
 
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