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Special Purpose Motors
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| Nagpur Motors offered a variety of special purpose motors such as |
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Motors for different supply conditions |
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Multi speed Motors |
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Inverter Duty Motors |
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Low Vibration Class Motors |
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Torque Motors |
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Brake Motors |
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Motors for Cooling Tower |
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Geared Motors |
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Crane Duty Motors |
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Special Mechanical Designs |
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Unbalance (Vibratory) Motors |
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These motors are designed to meet specific requirements as per customer’s applications. With direct interaction with the customers the delivery periods are very quick. Additional information on these is given under individual headings. |
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Motors for different supply conditions |
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Standard motors are designed for 415 Volts +/- 10% and 50 Hz +/- 5% supply. Motors for Voltages from 110 to 550 and different frequencies e.g. 60 Hz are supplied regularly. Even 42 Volt motors are offered against specific requirement. Motors for dual voltages / frequencies can also be supplied depending on combinations. |
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Multi Speed Motors |
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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 preposition 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. |
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FRAME-WISE 2-SPEED MOTOR RATINGS |
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1500/3000 RPM (4 / 2 POLE) |
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750/1500 RPM (8 / 4 POLE) |
FRAME |
KW |
HP |
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FRAME |
KW |
HP |
63 |
0.12./0.18 |
0.16/0.25 |
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71 |
0.30/0.45 |
0.4/0.6 |
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71 |
0.07/0.12 |
0.1/0.16 |
80 |
0.6/0.8 |
0.8/1.1 |
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80 |
0.22/0.45 |
0.3/0.6 |
90 L |
1.3/1.6 |
1.7/2.2 |
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90 L |
0.45/0.9 |
0.6/1.2 |
100 L |
2.2/3 |
3.0/4.0 |
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100 L |
0.9/1.5 |
1.2/2.0 |
112 M |
3.2/4 |
4.2/5.5 |
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112 M |
1.3/2.2 |
1.8/3.0 |
132 S |
4/5.5 |
5.5/7.5 |
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132 S |
2.2/3.3 |
3/4.5 |
132 M |
6.5/8.2 |
8.7/11 |
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132 M |
3/4.5 |
4.0/6.0 |
160 M |
9.0/11.0 |
12.0/15.0 |
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160 M |
4.9/7.5 |
6.5/10 |
160 L |
12.0/15.0 |
16.0/20.0 |
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160 L |
6.8/10.5 |
9.0/14.0 |
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1000/1500 RPM (6 / 4 POLE) |
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750/1000 RPM (8 / 6 POLE) |
FRAME |
KW |
HP |
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FRAME |
KW |
HP |
71 |
0.12/0.15 |
0.16/0.2 |
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71 |
0.06/0.09 |
0.08/0.12 |
80 |
0.3/0.37 |
0.4/0.5 |
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80 |
0.12/0.18 |
0.16/0.24 |
90 L |
0.6/0.9 |
0.8/1.2 |
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90 L |
0.3/0.45 |
0.4/0.6 |
100 L |
0.9/1.3 |
1.2/1.8 |
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100 L |
0.55/0.75 |
0.75/1 |
112 M |
1.3/2 |
1.8/2.7 |
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112 M |
0.75/1.2 |
1/1.6 |
132 S |
2.2/3.3 |
3.0 /4.5 |
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132 S |
1.3/2 |
1.8/2.7 |
132 M |
3/4.5 |
4.0/6.0 |
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132 M |
2/2.7 |
2.7/3.6 |
160 M |
4.0/6.0 |
5.5/8.0 |
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160 M |
3.0/4.0 |
4/5.5 |
160 L |
6.0/9.0 |
8.0/12.0 |
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160 L |
4/5.5 |
5.5/7.5 |
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500/3000 RPM (12 / 2 POLE) |
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500/1000 RPM (12 / 6 POLE) |
FRAME |
KW |
HP |
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FRAME |
KW |
HP |
100 L |
0.22/1.8 |
0.3/2.5 |
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100 L |
0.25/0.55 |
0.33/0.75 |
112 M |
0.4/2.5 |
0.55/3.3 |
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112 M |
0.45/0.9 |
0.6/1.2 |
132 M |
1.0/5.0 |
1.3/6.7 |
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132 S |
0.9/1.8 |
1.2/2.4 |
160 L |
2.0/11 |
2.7/15 |
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132 M |
1.2/2.4 |
1.6/3.2 |
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160 M |
1.5/3 |
2.0/4.0 |
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160 L |
2.1/4 |
2.8/5.5 |
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750/3000 RPM (8 / 2 POLE) |
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1000/3000 RPM (6 / 2 POLE) |
FRAME |
KW |
HP |
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FRAME |
KW |
HP |
80 |
0.15/0.45 |
0.2/0.6 |
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80 |
0.22/0.45 |
0.3/0.6 |
90L |
0.3/1.1 |
0.4/1.5 |
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90L |
0.5/1.1 |
0.67/2 |
100L |
0.37/2.5 |
0.5/1.8 |
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100L |
0.7/1.8 |
0.9/2.5 |
112M |
0.7/2.5 |
0.9/3.3 |
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112M |
1.5/2.2 |
2.0/3.0 |
132M |
1.5/5 |
2/6.7 |
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132M |
2/0.55 |
2.7/7.5 |
160L |
3.7/11 |
5.0/15.0 |
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160L |
5.0/11.0 |
6.7/15 |
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In this connection the following points may be noted. |
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4/2P, 8/4P & 12/6P motors are single winding D/YY, Dahlander connection motor. |
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Other motors have separate Y (star) connected windings. |
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The ratings indicated are maximum for particular frames. |
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In separate winding motors, it may be possible to increase rating of one polarity, by reducing rating of other polarity |
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The ratings shown above are for S1 duty. These may change for short time duty, more number of starts etc. |
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The ratings are for TEFC construction, it may be possible to increase the ratings by force cooling. |
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Inverter Duty Motors |
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Squirrel Cage Induction Motors have been known to be the sturdiest of all rotating machines. However, they have a basic limitation by way of being not amenable to speed control. Therefore, over the years, other arrangements like use of DC motors, Eddy current controls etc. have been used. These are expensive, apart from having recurring maintenance problems. In the recent years, however, speed control of induction motors is by supplying these through an Inverter i.e. variable frequency supply. Supply through variable frequency drive is also be found to result in substantial energy saving in many applications. Variable frequency supplied motor can also be started softly with low starting current. Within narrow range of say + 10% frequency variation, a standard motor could very well be used, depending on the actual load conditions. However, variation of frequency especially over a wider range results in additional stress on the motor and the motors have to be specially designed to meet these conditions. |
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Nagpur Motors specializes in designing motors for variable frequency drive supply to obtain a most optimum and economical design. Nagpur Motors have been supplying such specially designed motors for frequency variations form 3 or 5 Hz up to 200Hz or more. |
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These NM motors have following specialties. |
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Motors are designed for inherent low magnetic flux densities.
The motors have class ‘F’ insulation and strengthened insulation by way of thicker insulation at certain points, improved overhand binding, additional varnishing etc. Motors are generally in Totally Enclosed Force Cooled version having a separate motor / fan mounted on the primary motor, which cools the main motor. Totally Enclosed Surface Cooled motors eliminating external fan are also offered in many cases. Rotors are balanced to higher degree. Depending on the range of RPM, special bearings are used and tolerances on the shaft and end covers are controlled to higher precision. |
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The motors are generally designed for giving nearly constant horsepower above the base frequency (50Hz) and constant torque below this. It is necessary to know the speed range and the torque requirements at various speeds. It may be mentioned that performance and loadability of motors also depends on the converter design, since the deviation from sinusoidal supply depends on type of converter, its carrier frequency etc. |
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Low Vibration Class Motors |
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Standard Motors are supplied with normal Vibration class as per IS 12075. Motors of lower Vibration class A, B, or C as per IS are also supplied against request. These motors are specially manufactured with closer control on tolerances, precise dynamic balancing etc. The necessary testing equipments / arrangements are available for this purpose. |
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