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#160960 03/28/07 03:32 AM
Joined: Sep 2005
Posts: 97
J
Member
Hi,

We have a motor generator frequency converter that we are reinstalling. I only have the instruction sheet in German. The terminals are marked U,V,W for the excitation Z,X,Y for the motor W,V,U for the output. What do they stand for? Also, the phases are marked R,S,T.

As this set doesnt have a neutral would it be possible to derive a neutral from the generator earth?

I should point out that I am not doing the work, I just want to understsnd smile

If anyone feels generous enough to translate the german PDF to english, let me know smile


I took my time, I hurried up, The choice was mine, I didn't think enough
Joined: Sep 2002
Posts: 1,498
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C
C-H Offline
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The first three are older designations for the phases:

L1 = R
L2 = S
L3 = T

I suspect that the other six letters can be used to describe the leads for delta / wye connections. E.g. you have the choice of connecting the Z X Y to either the phases (delta) or wiring them together to create a the neutral (wye).

Joined: Dec 2005
Posts: 866
Likes: 4
R
Member
In The Netherlands and Germany the old phase indications were R, S, T. for the 3Ø, 220/380 Volts supply and CH is correct.

L1 is R
L2 is S
L3 is T

U, V, W are usually the first set of terminals into the motor and are used for STAR starting,

The second set of terminals are Z, X, Y and are used for DELTA operation of the motor.

If you are wiring it up, it is important that this sequence is adherred too, otherwise the risk may exist that by wire swapping the rotation between star and delta may be reversed with all possible damage to equipment or operator of the machine.


The product of rotation, excitation and flux produces electricty.
Joined: Dec 2005
Posts: 866
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R
Member
If the PDF file isn't too big i will give translation a go. I can read, write and speak some German.

I would say that this motor generator set up would be run via a star / delta switch for starting, to reduce large inrush currents from the supply mains.
Usually these sets are started with no load, when up to speed the load is applied.

When i served my time in the Royal Dutch Airforce in The Netherlands we used rotaty converters to "generate 1Ø, 115Volts, and 3Ø, 416 Volts at 400 Hz, from the 220/380 mains at a base load of 600 Amperes.

RF.

Last edited by RODALCO; 03/28/07 02:15 PM.

The product of rotation, excitation and flux produces electricty.
Joined: Dec 2005
Posts: 866
Likes: 4
R
Member
I need to see a schema from this set up if a neutral can be derived from this machine.

If the single phase load was balanced, or very small, eg to drive a relay coil or hour meter I can't see not too much of a problem to use the Earth connection.

If a larger 1Ø load has to be taken off, the starpoint from the motor generator output needs to be accessed, as done with normal generators.


The product of rotation, excitation and flux produces electricty.
Joined: Jul 2004
Posts: 783
L
Member
Originally Posted by johno12345
As this set doesnt have a neutral would it be possible to derive a neutral from the generator earth?


What reason do you want the Neutral for? Small single phase loads, large single phase loads, referencing output to earth, ground fault detection, etc, ...

Larry C

Joined: Sep 2005
Posts: 97
J
Member
I only want a neutral as we are installing RCBOs on the load side. The neutral would really only be for the Test button and completeness and to match the other sets which arent the same but have a neutral.
I have the PDF at work which has a schematic of it. Could one of the mods put the file on the ecn server so we can have a link? The only loads are 3 phase.


I took my time, I hurried up, The choice was mine, I didn't think enough

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