3 PHASE MOTOR DELTA OR WYE

[PURE]

Wiring a new screw drive compressor for a customer with 208 3/0 Wye service on site. 2 existing older compressors next to this one are wired accordingly, Wye connections. The new 230/460v 20 HP Lincoln motor on the generator has 4 diagrams, high delta, high wye and low delta, low wye. I choose the Low Wye diagram. the manual states the motor will run okay on 208v service.

After completing the installation, the start up company who sold the compressor came out and informed my customer that the unit should have been wired low Delta. Why Is this? I thought the incoming voltage dictated the motor wiring type.

 

[don_resqcapt19]

The motor does not care about the type of system that supplies it. It only wants to see the correct voltage across its windings. Your motor will have six sets of windings that are rated at 230 volts. If you are using a standard across the line starter, you will wire the windings in a single delta with two windings in series on each side of the delta for the high voltage connection. You would wire it in a double delta with two windings in parallel on each side of the delta. In both cases each winding will see 230 volts.

The wye connection is only used for a wye start/delta run system. That is a type of reduced voltage starting that is sometimes used to reduce the starting current. Not near as common now as it once was. In the wye connection each winding will see ~133 volts.

 

[topgone]

Wiring a new screw drive compressor for a customer with 208 3/0 Wye service on site. 2 existing older compressors next to this one are wired accordingly, Wye connections. The new 230/460v 20 HP Lincoln motor on the generator has 4 diagrams, high delta, high wye and low delta, low wye. I choose the Low Wye diagram. the manual states the motor will run okay on 208v service.

After completing the installation, the start up company who sold the compressor came out and informed my customer that the unit should have been wired low Delta. Why Is this? I thought the incoming voltage dictated the motor wiring type.

Do you have the part number? That could help others in digesting what animal you have in there.

 

[kwired]

The motor does not care about the type of system that supplies it. It only wants to see the correct voltage across its windings. Your motor will have six sets of windings that are rated at 230 volts. If you are using a standard across the line starter, you will wire the windings in a single delta with two windings in series on each side of the delta for the high voltage connection. You would wire it in a double delta with two windings in parallel on each side of the delta. In both cases each winding will see 230 volts.

The wye connection is only used for a wye start/delta run system. That is a type of reduced voltage starting that is sometimes used to reduce the starting current. Not near as common now as it once was. In the wye connection each winding will see ~133 volts.

I agree. He has a dual voltage motor as well as one designed for wye starting - delta running. If starting across the line or with a VFD or soft start you connect it in delta configuration for the applied voltage.