Motor Connections
Nema Nomenclature
Single Phase
Three Phase
- Constant torque - 6 leads
- Variable torque - 6 leads
- Constant horsepower - 6 leads
- Single voltage - 6 leads
- Single and dual voltage (wye-delta) - 6 leads
- Dual voltage - 9 leads (wye connected)
- Dual voltage - 9 leads (delta connected)
- Dual voltage - 12 leads (external wye connected)
- Dual voltage - 12 leads (wye-connected start & delta-connected run)
IEC Nomenclature
Three Phase
Single Voltage
NEMA NOMENCLATURE - SINGLE PHASE - SINGLE VOLTAGE
Dual Voltage
(Run winding only)
Start winding is always at low voltage rating; capacitor should be rated accordingly.
NEMA NOMENCLATURE - SINGLE PHASE - DUAL VOLTAGE
Dual Voltage
(Run and start winding)
Capacitors in start windings are rated for lower voltage.
NEMA NOMENCLATURE - SINGLE PHASE - DUAL VOLTAGE
Constant Torque Connection - 6 Leads
Low-speed horsepower is half of high-speed horsepower.
NEMA NOMENCLATURE - THREE PHASE - CONSTANT TORQUE
Variable Torque Connection - 6 Leads
Low-speed horsepower is one-fourth of high-speed horsepower.
NEMA NOMENCLATURE - THREE PHASE - VARIABLE TORQUE
Constant Horsepower Connection - 6 Leads
Horsepower is the same at both speeds.
NEMA NOMENCLATURE - THREE PHASE - CONSTANT HORSEPOWER
Single Voltage
NEMA NOMENCLATURE - THREE PHASE - SINGLE VOLTAGE
Single Voltage External Wye Connection
Single Voltage
Dual Voltage*
*Voltage ratio: 1.732 to 1
NEMA NOMENCLATURE - THREE PHASE - SINGLE VOLTAGE
Dual Voltage Wye-Connected
NEMA NOMENCLATURE - THREE PHASE - DUAL VOLTAGE
Dual Voltage Delta-Connected
NEMA NOMENCLATURE - THREE PHASE - DUAL VOLTAGE
Dual Voltage External Wye-Connected
NEMA NOMENCLATURE - THREE PHASE - DUAL VOLTAGE
Dual Voltage Wye-Connected Start Delta-Connected Run
NEMA NOMENCLATURE - THREE PHASE - DUAL VOLTAGE
IEC Constant Torque Connection - 6 Leads
Low-speed horsepower is half of high-speed horsepower.
IEC NOMENCLATURE - THREE PHASE - CONSTANT TORQUE
IEC Variable Torque Connection - 6 Leads
Low-speed horsepower is one-fourth of high-speed horsepower.
IEC NOMENCLATURE - THREE PHASE - VARIABLE TORQUE
IEC Single Voltage Wye-Delta Connections
IEC NOMENCLATURE - THREE PHASE - SINGLE VOLTAGE
IEC Dual Voltage*Wye-Delta Connections
*Voltage ratio: 1.732 to 1
IEC NOMENCLATURE - THREE PHASE - DUAL VOLTAGE
IEC Dual Voltage Wye-Connected StartDelta-Connected Run
Delta-Connected Run
IEC NOMENCLATURE - THREE PHASE - DUAL VOLTAGE