3ph wye rewire 1

[judylev]

I test started a 30kw Solair oil screw air compressor but I am worried about installing it at a remote mine site. (model S35E Germany 1978, 3.3 m3/mi,n, 7.5 bar, 1,500 rpm.) The importer in Lima Peru says he modified the SCHORCH 12 wire 3 ph. to 220/440, 60Hz (data tag= KN5180L-BBO 30Z, Din Baugr= 180L, IP= 23, Delta/Y = 220/380v, 102/59A, KW= 30, Cos.= 0.87, Sol KL= F,I, RPM= 1440, Hz= 50).

The new motor wiring options are parallel and series wye and I want to use the high voltage configuration. I don't have a schematic for the machine but there is a delta/Y starting circuit in the cabinet that has been disabled.

My question is, if in fact some rewinding and/or retapping has been done (I see new red lead paint inside) then will I still be producing the torque that the pump requires while in the Wye mode?

 

[waross]

You have basically 220 V, 50 Hz windings. The V/H ratio gives a rating of 264 V, 60 Hz. Put that in wye and you have a voltage rating of 457 V, 60 Hz. Close enough to the NEMA standard 460 Volts.
You should have the same torque, but your RPM will be about 1750 RPM. You should evaluate the torque requirment of the compressor at 1750 RPM.
As for the retapping, the original machine was a 6 lead machine. That was suitable for 440V or 460 V but the importer would have had to bring out extra leads to allow for a 220 V (230 V) 60 Hz connection.
Three jumpers between coil groups have been cut and been brought out as 6 more leads.

Bill
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