Dual speed or Multi speed motors against specific requirements are available. Amongst these, 2-speed motors are very popular and have been found to be an economically viable praposition in many applications. The changeover of speed can be done by a simple special switch or by suitable connections in the panel. A wide range of frame-wise standardized ratings as given in the table hereunder are available.
FRAME-WISE 2-SPEED MOTOR RATINGS
1500/3000 RPM (4 / 2 POLE) 750/1500 RPM (8 / 4 POLE)
FRAME KW HP   FRAME KW HP
63 0.12./0.18 0.16/0.25        
71 0.30/0.45 0.4/0.6   71 0.07/0.12 0.1/0.16
80 0.6/0.8 0.8/1.1   80 0.22/0.45 0.3/0.6
90 L 1.3/1.6 1.7/2.2   90 L 0.45/0.9 0.6/1.2
100 L 2.2/3 3.0/4.0   100 L 0.9/1.5 1.2/2.0
112 M 3.2/4 4.2/5.5   112 M 1.3/2.2 1.8/3.0
132 S 4/5.5 5.5/7.5   132 S 2.2/3.3 3/4.5
132 M 6.5/8.2 8.7/11   132 M 3/4.5 4.0/6.0
160 M 9.0/11.0 12.0/15.0   160 M 4.9/7.5 6.5/10
160 L 12.0/15.0 16.0/20.0   160 L 6.8/10.5 9.0/14.0
1000/1500 RPM (6 / 4 POLE) 750/1000 RPM (8 / 6 POLE)
FRAME KW HP   FRAME KW HP
71 0.12/0.15 0.16/0.2   71 0.06/0.09 0.08/0.12
80 0.3/0.37 0.4/0.5   80 0.12/0.18 0.16/0.24
90 L 0.6/0.9 0.8/1.2   90 L 0.3/0.45 0.4/0.6
100 L 0.9/1.3 1.2/1.8   100 L 0.55/0.75 0.75/1
112 M 1.3/2 1.8/2.7   112 M 0.75/1.2 1/1.6
132 S 2.2/3.3 3.0 /4.5   112 M 1.3/2 1.8/2.7
132 M 3/4.5 4.0/6.0   112 M 2/2.7 2.7/3.6
160 M 4.0/6.0 5.5/8.0   160 M 3.0/4.0 4/5.5
160 L 6.0/9.0 8.0/12.0   160 L 4/5.5 5.5/7.5
500/3000 RPM (12 / 2 POLE) 500/1000 RPM (12 / 6 POLE)
FRAME KW HP   FRAME KW HP
100 L 0.22/1.8 0.3/2.5   100 L 0.25/0.55 0.33/0.75
112 M 0.4/2.5 0.55/3.3   112 M 0.45/0.9 0.6/1.2
132 M 1.0/5.0 1.3/6.7   132 S 0.9/1.8 1.2/2.4
160 L 2.0/11 2.7/15   132 M 1.2/2.4 1.6/3.2
        160 M 1.5/3 2.0/4.0
        160 L 2.1/4 2.8/5.5
750/3000 RPM (8 / 2 POLE) 1000/3000 RPM (6 / 2 POLE)
FRAME KW HP   FRAME KW HP
80 0.15/0.45 0.2/0.6   80 0.22/0.45 0.3/0.6
90L 0.3/1.1 0.4/1.5   90L 0.5/1.1 0.67/2
100L 0.37/2.5 0.5/1.8   100L 0.7/1.8 0.9/2.5
112M 0.7/2.5 0.9/3.3   132 M 1.5/2.2 2.0/3.0
132M 1.5/5 2/6.7   132M 2/0.55 2.7/7.5
160L 3.7/11 5.0/15.0   160 L 5.0/11.0 6.7/15
In this connection the following points may be noted :
  • 4/2P, 8/4P & 12/6P motors are single winding D/YY, Dahlander connection motor.
  • Other motors have separate Y (star) connected windings.
  • The ratings indicated are maximum for particular frames.
  • In separate winding motors, it may be possible to increase rating of one polarity, by reducing rating of other polarity
  • The ratings shown above are for S1 duty. These may change for short time duty, more number of starts etc.
  • The ratings are for TEFC construction, it may be possible to increase the ratings by force cooling.