Brochure
169
Decimal-Millimeter Equivalents
Horsepower and Torque
Horsepower is the common unit of mechanical power.
hp = Force x Feet per Minute
33000
hp = Torque in In.-Lbs. x rpm
63025
One hp = .746 Kilowatt
One Kilowatt = 1.34 H.P.
Torque is a twisting moment or turning effort.
Torque in inch-pounds = Force x Lever Arm (Inches)
Torque in inch-pounds = 63025 x hp
rpm
The following table gives the torque in inch-pounds for
one hp at various speeds.
Torque at One Horsepower
Minimum Sheave Sizes
NEMA
®
Standards
The National Electrical Manufacturers Association
recommends certain limitations on sheave diameter
and width for satisfactory motor operation. The selected
sheave diameter should not be smaller nor the width
greater than the dimensions below. These dimensions
are from NEMA Standard MG1-14.42.
To obtain the minimum pitch diameters for flat belt,
Gearbelt
®
, Poly-V*, chain or gear drives, multiply the
358 sheave pitch diameters in the table above by the
following factors:
To find torque at any horsepower multiply values in table above by the
horsepower required.
For intermediate speeds interpolate values in table above or solve the
torque formula above.
GeneralInformation
R.P.M. In-Lbs. R.P.M. In-Lbs. R.P.M. In-Lbs. R.P.M. In-Lbs.
3500 18 580 109 90 700 14 4502
3000 21 500 126 80 788 12 5252
2400 26 400 158 70 900 10 6300
2000 32 300 310 60 1050 8 7878
1750 36 200 315 50 1260 6 10504
1600 39 180 350 40 1576 5 12605
1200 53 160 394 30 2101 4 15756
1160 54 140 450 20 3151 3 21008
1000 63 120 525 18 3501 2 31513
870 72 100 630 16 3939 1 63025
Drive Factor
Chain 0.70
Flat Belt (Single Ply) 1.33
Gearbelt 0.90
Helical Gear 0.85
Poly-V 1.00
Spur Gear 0.75
Frame
Horsepower at
V-Belt Sheave (Inches)
Conventional 358
Sync, Speed, rpm
A, B, C, D, and E
Sections
3V, 5V, and 8V
Sections
3600 1800 1200 900
Min.
Pitch
Dia.
Max
Width
Min.
Outside
Dia
Max.
Width
143T 1 1/2 - 3/4 1/2 2.2 4 1/4 2.2 2 1/4
143T 2-3 - 1 3/4 2.4 4 1/4 2.4 2 1/4
182T 3 3 1 1/2 1 2.4 5 1/4 2.4 2 3/4
182T 5 - - 5 1/4 2.4 2 3/4
184T - - 2 1 1/2 2.4 5 1/4 2.4 2 3/4
184T 5 - - - 2.6 5 1/4 2.4 2 3/4
184T 7 1/2 - - 3.0 5 1/4 3.0 2 3/4
213T 7 1/2-10 7 1/2 3 2 3.0 6 1/2 3.0 3 3/8
215T 10 - 5 3 3.0 6 1/2 3.0 3 3/8
215T 15 10 - 3.8 6 1/2 3.8 3 3/8
254T 15 - 7 1/2 5 3.8 6 1/2 3.8 4
254T 20 15 - - 4.4 6 1/2 4.4 4
256T 20-25 - 10 7 1/2 4.4 6 1/2 4.4 4
256T - 20 - 4.6 6 1/2 4.4 4
284T - - 15 10 4.6 9 4.4 4 5/8
284T - 25 - 5.0 9 4.4 4 5/8
286T - 30 20 15 5.4 9 5.2 4 5/8
-
324T - 40 25 20 6.0 10 1/4 6.0 5 1/4
326T - 50 30 25 6.8 10 1/4 6.8 5 1/4
364T - - 40 30 6.8 11 1/2 6.8 5 7/8
364T - 60 - 7.4 11 1/2 7.4 5 7/8
365T - - 50 40 8.2 11 1/2 8.2 5 7/8
365T - 75 - - 9.0 11 1/2 8.6 5 7/8
404T - - 60 - 9.0 14 1/4 8.0 7 1/4
404T - - 50 9.0 14 1/4 8.4 7 1/4
404T - 100 - 10.0 14 1/4 8.6 7 1/4
405T - 75 60 10.0 14 1/4 10.0 7 1/4
405T - 100 - 10.0 14 1/4 8.6 7 1/4
405T - 125 - 11.5 14 1/4 10.5 7 1/4
444T - - 100 - 11.0 16 3/4 10.0 8 1/2
444T - - - 75 10.5 16 3/4 9.5 8 1/2
444T - 125 - - 11.0 16 3/4 9.5 8 1/2
444T - 150 - - 10.5 8 1/2
445T - - 125 - 12.5 16 3/4 12.0 8 1/2
445T - - - 100 10.5 16 3/4 12.0 8 1/2
445T - 150 - - - - 10.5 8 1/2
445T - 200 - - - - 13.2 8 1/2
Fractional Decimal M.M. Fractional Decimal M.M.
1/64 .015625 0.397 33/64 .515625 13.097
1/32 .03125 .794 17/32 .53125 13.494
3/64 .046875 1.191 35/64 .546875 13.891
1/16 .0625 1.588 9/16 .5625 14.288
5/64 .078125 1.984 37/64 .578125 14.684
3/32 .09375 2.381 19/32 .59375 15.081
7/64 .109375 2.778 39/64 .609375 15.478
1/8 .125 3.175 5/8 .625 15.875
9/64 .140625 3.572 41/64 .640625 16.272
5/32 .15625 3.969 21/32 .65625 16.669
1
1/64 .171875 4.366 43/64 .671875 17.066
3/16 .1875 4.763 11/16 .6875 17.463
13/64 .203125 5.159 45/64 .703125 17.859
7/32 .21875 5.556 23/32 .71875 18.256
15/64 .234375 5.953 47/64 .734375 18.653
1/4 .250 6.350 3/4 .750 19.050
17/64 .265625 6.747 49/64 .765625 19.447
9/32 .28125 7.144 25/32 .78125 19.844
19/64 .296875 7.541 51/64 .796875 20.241
5/16 .3125 7.938 13/16 .8125 20.638
21/64 .328125 8.334 53/64 .828125 21.034
11/32 .34375 8.731 27/32 .84375 21.431
23/64 .359375 9.128 55/64 .859375 21.828
3/8 .375 9.525 7/8 .875 22.225
25/64 .390625 9.922 57/64 .890625 22.622
13/32 .40625 10.319 29/32 .90625 23.019
27/64 .421875 10.716 59/64 .921875 23.416
7/16 .4375 11.113 15/16 .9375 23.813
29/64 .453125 11.509 61/64 .953125 24.209
15/32 .46875 11.906 31/32 .96875 24.606
31/64 .484375 12.303 63/64 .984375 25.003
1/2 .500 12.700 1 1.000 25.400
* The following trademarks are believed to be the trademark and/or trade names of their respec-
tive owners, and are not owned or controlled by Emerson Power Transmission. NEMA: National
Electrical Manufacturers Association; Poly-V: Veyance Technologies, Inc.