| Soft Start Application
|
Load Conditions
|
NEMA-Preferred
Motor Design |
SENTROL EM3
Inrush Rating |
Standard Inrush Loads
-Centrifugal rotary pumps -Fans with normal inertia -Motor-Generator sets -Sanders -Grinders -Circular saws -Pulp grinders -Shapers and planers -Lathes -Milling machines |
Normal Starting Torque
for continuous duty. Load fluctuations are infrequent. Has some capacity to handle minor, occasional Overloads. Likely to draw <300% FLA on a reduced voltage start. |
NEMA Design B:
Low Starting Current, Normal Torque, Normal Slip. |
18EM3:
rated for 300% FLA at 20 seconds. Power circuit sized for normal reduced voltage starting current. |
High Inrush Loads
-Reciprocating, positive displacement pumps -Air compressors -Refrigeration compressors -Conveyors -Crushers without flywheels -Dough mixers -Hammer mills -Ball mills -Turntables -Car pullers |
Heavy Starting Torque
continuous or inter- mittent duty. Has some overload capacity.May draw >300% FLA. |
NEMA Design C:
Low Starting Current High Breakaway Torque Normal Slip |
18EM3-H:
rated for 600% FLA for 5 seconds, 500% for 20 seconds. Power circuit is sized for higher current levels which the motor could draw at start. |
Hard to Start Loads
-Hoists,Lifts and Cranes -Elevators -Machine tools -Punch presses -Crushers with flywheels -High inertia flywheels |
High Starting Torque
intermittent or reversing service, plugging service, heavy or fluctuating loads. Likely to draw >> 300% FLA at starting. |
NEMA Design D:
High starting Current High Breakaway Torque High Slip |
18EM3-H:
rated for 600% FLA for 5 seconds, 500% for 20 seconds. Power circuit is sized for higher current levels which the motor could draw at start. |
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