EASA Electrical Engineering Handbook

Terminal Markings and Connections
Three-Phase Motors-Two Speed Single Winding

NEMA Nomenclature – 6 Leads

Constant Torque Connection
Low-speed horsepower is half of high-speed horsepower.*

Constant Torque Connection

SpeedL1L2L3Typical Connection
High6451 & 2 & 3 Join2 WYE
Low1234-5-6 Open1 DELTA

 

Variable Torque Connection
Low-speed horsepower is one-fourth
of high-speed horsepower.*

Variable Torque Connection

SpeedL1L2L3Typical Connection
High6451 & 2 & 3 Join2 WYE
Low1234-5-6 Open1 DELTA

 

Constant Horsepower Connection
Horsepower is the same at both speeds.

Constant Horsepower Connection

SpeedL1L2L3Typical Connection
High6451-2-3 Open2 DELTA
Low1234 &1

*CAUTION: On European motors horsepower variance with speed may not be the same as shown above.

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Terminal Markings and Connections
Three-Phase Motors-Two Speed, Single Winding

 IEC Nomenclature – 6 Leads

Constant Torque Connection

Constant Torque Connection

SpeedL1L2L3Typical Connection
High2W2U2V1U & 1V & 1W Join2
Low11V1W2U-2V-2W Open1

 

Variable Torque Connection

Variable Torque Connection
SpeedL1L2L3Typical Connection
High2W2U2V1U & 1V & 1W Join2
Low11V1W2U-2V-2W Open1

 

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