Motor Wiring
Motor Wiring
• Do not handle the unit when cables are live . Be sure to turn-off the power; otherwise electric shock may result .
• Connect the power cables to the unit according to the connection diagram shown inside the terminal box or in the
maintenance manual; otherwise electric shock or fire may result .
• Correctly ground the grounding bolt; otherwise electric shock may result .
• Keep all wiring and electrical parts dry and moisture free .
• Follow local electrical codes and regulations when wiring; otherwise burning, electrical shock, injury and/or fire may result .
• The motor is not equipped with an overload device . Sumitomo strongly recommends that another protective device
(i .e .: ground fault interrupters, etc .), in addition to an overload device, be installed in order to prevent burning, electric shock, personal
injury and/or fire .
• For single phase motors, exercise caution so as to not damage the vinyl cover of the starting capacitor, otherwise shock may result .
• For brakemotors, do not electrify a brake coil continuously when the motor is stopped otherwise the brake coil may burn and
fire may result .
•
For brakemotors, install the rectifier where the temperature is less than 140°F
(60°C)
•
Long wires cause the voltage to drop . Select cables with appropriate diameter so that the voltage drop will be
less than 2% .
•
After wiring the motor, check that the terminal box mounting bolts are tight .
Measuring Insulation Resistance
When measuring insulation resistance, disconnect the motor from the control panel . Check the motor separately .
Never touch the terminals when measuring insulation resistance otherwise electrical shock may occur .
Measure the insulation resistance before wiring . Insulation resistance varies according to the motor voltage, insulation type, coil
temperature, humidity, length of operation, test electrification time, etc .
Under most conditions, the insulation resistance exceeds the value shown in this table:
Wired connections
must be wrapped in
insulating tape
(not shown)
Power Source Side
Motor Side
Mega-Ohm
Insulation Resistance
500V
1M (Ω)
Table 22 . Insulation Resistance
Figure 3 . Terminal Ring Wiring Connection
Wiring Guidelines
This section details wiring for standard Sumitomo three-phase motors and brakemotors . If using a motor manufactured by a company other than
Sumitomo, please refer to that manufacturer’s instruction manual for wiring, operating and maintenance details . When wiring motors into the
power supply, Sumitomo recommends the use of terminal rings to facilitate the connection:
A drop in resistance may be attributed to poor insulation . In such
case, do not turn on the power . Contact the nearest Sumitomo
representative, distributor, or sales office .
Figure 4 . Three-Phase WYE Connection Motor
Figure 6 . Three-Phase Motor, 575V, 60Hz
