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
Speed L1 L2 L3 Typical Connection
High 6 4 5 1 & 2 & 3 Join 2 WYE
Low 1 2 3 4-5-6 Open 1 DELTA

 

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

Variable Torque Connection
Speed L1 L2 L3 Typical Connection
High 6 4 5 1 & 2 & 3 Join 2 WYE
Low 1 2 3 4-5-6 Open 1 DELTA

 

Constant Horsepower Connection
 Horsepower is the same at both speeds.

Constant Horsepower Connection

Speed L1 L2 L3 Typical Connection
High 6 4 5 1-2-3 Open 2 DELTA
Low 1 2 3 4 & 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
Speed L1 L2 L3 Typical Connection
High 2W 2U 2V 1U & 1V & 1W Join 2
Low 1 1V 1W 2U-2V-2W Open 1

 

Variable Torque Connection

 Variable Torque Connection
Speed L1 L2 L3 Typical Connection
High 2W 2U 2V 1U & 1V & 1W Join 2
Low 1 1V 1W 2U-2V-2W Open 1

 

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