Document ExabRgLOX1qxZzvx3m0vgRo40

Heating Ventilating Air Conditioning Guide 1938 CURRENT Table 1. Classification of Motors Speed Charac teristics Full Voltage Starting Torque Starting Current Hp Range Ttpb OP Application Bee Footnote* 1. Shunt Direct 2. Compound 3. Series Constant Speed Drives Constant Medium Medium All Constant High or Variable Variable High Medium All Medium Small (a) Fans and (c) Centrifugal Pumps (b) (c) (e) Reci procating Pumps and frequent or hand starting (d) Fans direct connected Poly phase 4. Squirrel Cage Constant Normal High All General Purpose 6-8 Times (a) Fans-and (c) Centrifugal Pumps 5. Squirrel Cage Constant Normal Medium Medium (a) Fans and Medium Torque 5-6 Times Small Centrifugal Pumps 6. Squirrel Cage High Torque Constant High Medium Medium 5-6 Times Small (6) Reciprocating; Pumps (e) and Compressors started loaded 7. Automatic Start Constant High High Torque . Low 3 Times Medium (b) Reciprocating Pumps (e) and Compressors started loaded 8. Slip Ring Wound Rotor Constant High Low All 1-3 Times with sec ondary control (a) and Hoists (b) Reciprocating Pumps (c) and Frequent (ie) or Hand Start 9. Synchronous High Speed Constant Medium Medium Medium (a) Fans and Cen 5-TTimes Large trifugal Pumps 10. Synchronous Low Speed Constant Low Low Medium (a) Reciprocating 3-4 Times Large Compressors Start ing Unloaded Single phase 11. Capacitor Constant High Normal Medium (6) Pumps and Small Compressors 'Applications: a. Drives having medium or low starting torque and inertia (WR*) such as fans and centrifugal pumps or reciprocating pumps and compressors started unloaded. b. Drives having high starting torques, such as reciprocating pumps and compressors started loaded.' c. Similar to (a) except where frequent or hand starting (large WR*) requires a higher starting and accelerating torque. &. Fans direct connected. e. Stoker drives. 708 Chapter 38. Motors and Controls Current Table 1. Classification of Motors--(Continued) TYPE Speed Charac teristics Fou, Voltage Starting Torque Starting Current Hp Range Ttpe op Application See Footnote* Single phase - 12. Capacitor Fan Constant High Medium Medium (a). Fans--belted Small 13. Capacitor Fan Constant Low Medium Medium (d) Fans--direct Small 14. Capacitor Start Constant Any Induction Run Medium Medium (a) Fans Small . (b) Pumps and Compressors 15. Repulsion Induction Constant High Medium Medium () Fans Small () Pumps and Compressors 16. Repulsion Start Constant High Induction Run Medium Medium (o) Fans Small (b) Pumps and Compressors 17. Split Phase Constant Medium and Adjusttable Medium Frac tional (a) Fans (b) Pumps and Compressors Adjustable Speed Drives 18. Shunt Field Adjustment Constant Medium Medium All Direct 19. Shunt Armature Variable Medium Medium All Resistor (a) Fans and (e). Centrifugal Pumps (a) Fans and (e) Centrifugal Pumps 20. Squirrel Cage Variable Medium Medium Medium (a) Fans High Slip, Small Tapped Winding Poly phase . 21. Squirrel Cage Variable High Slip, Trans former Adjust ment Medium Medium Medium Small. (a) Fans 22; Squirrel Cage Constant Medium Separate Wind Multi- or High ing or Regrouped Speed Poles Low All (a) Fans (b) Pumps and (c) Compressors