Russian 220 voltage, how many phases?

[Nitzey]

I need to purchase metering pumps for a plant in St. Petersburg, Russia. One quote listed the motor as 220 V, single phase, while another had 220V, three phases? Which should it be?

 

[ScottyUK]

Shouldn't you be the one telling the supplier what you want? Ring the plant and ask them what they need. Or if it isn't yet built, ask the designers.

Generally 3-phase motors are more reliable than 1-phase types so if you have 220V single phase then you likely also have 380V 3-phase, and the latter would be a sensible choice.


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If we learn from our mistakes I'm getting a great education!

 

[Nitzey]

Thanks for your reply. I really did not think this through before posting the question. I am the designer of this plant, which is a new plant at an existing site. 380 V, 3 phase, 50 Hz comes into this site now, but we need to add more power, and a new motor control center is needed. The larger motors will be 380 V, 3 phase, but these three metering pumps are small. The lowest bids I have are 220 V, 3 phase if manual but 220 V, single phase if electronically controlled. My plan is two pumps electronically controlled and one manual.

 

[davidbeach]

If you have 380V 3-phase, you get 230V single phase for free, but 230V 3-phase costs you a transformer, a d perhaps a non-standard transformer to boot.

 

[ScottyUK]

Just check if the 220V 3-phase motor is delta connected because very often it could easily be changed to 380V star connected by a simple change of links at the terminal box, unless it's been deliberately designed to prevent this.


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If we learn from our mistakes I'm getting a great education!

 

[Nitzey]

Thanks for the good advice. This has been very helpful. What seems clear is that we should have all three metering pumps electronically controlled, and thus all will be 220 V, single phase.

 

[akselj]

There is no good reason whatever to use 1 phase 220V motors if you have acces to 3 phase 380 V.

The 3 phase motors are cheaper and more reliable, many small motors running 1 phase is really 3 phase motors with a capacitor to provide the turning field, these motors have a much lower torque than a 3 phase motor.

 

[cry22]

"but these three metering pumps are small" - Nitzey - Just how small are these pumps motors? our electrical engineers always told us that 3/4 HP and above, we should use 3 phase, 1/2 HP and below, use single phase.

Scott,

"very often it could easily be changed to 380V star connected by a simple change of links at the terminal box"

I was once told that changing a motor wiring in the field will result into losing your UL listing.

 

[ScottyUK]

cry22,

I honestly don't know - UL is just an interesting curiosity where I work. Our motors are designed so a voltage change requires a simple change of links in the temrinal box. UL must be a total pain in the ass if they object to something as simple as that.


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If we learn from our mistakes I'm getting a great education!

 

[davidbeach]

If it is listed as a multi-voltage motor there would no UL issues using either voltage per the manufacturer's instructions. If it were a motor theoretically capable of two voltages, but only listed for one and no instructions for changing voltages, then there be a voiding of the listing if you tear it apart and reconnect for another voltage.

 

[ScottyUK]

Thanks David.


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If we learn from our mistakes I'm getting a great education!