Electric Motors  Torque vs. Power and Speed
Electric motor output power and torque vs. rotation speed.
 Work is the result of a force acting over some distance. Work is quantified in joules (Nm) or footpounds.
 Torque is a rotating force produced by a motor’s crankshaft. The more torque the motor produces, the greater is its ability to perform work. Since torque is a vector acting in a direction it is commonly quantified by the units Nm or poundfeet.
 Power is how rapidly work is accomplished  work in a given amount of time. Power is quantified in watts (J/s) or horse power.
Note that the driving force of an electric motor is torque  not horsepower. The torque is the twisting force that makes the motor running and the torque is active from 0% to 100% operating speed.
The power produced by the motor depends on the speed of the motor and is
 zero at 0% speed, and
 normally at it's top at operating speed
Note !  the full torque from zero speed is a major advantage for electric vehicles.
For full table  rotate the screen!
Power  Motor Speed (rpm)  

3450  2000  1750  1000  500  
Torque  
hp  kW  (lb_{f} in)  (lb_{f} ft)  (Nm)  (lb_{f} in)  (lb_{f} ft)  (Nm)  (lb_{f} in)  (lb_{f} ft)  (Nm)  (lb_{f} in)  (lb_{f} ft)  (Nm)  (lb_{f} in)  (lb_{f} ft)  (Nm) 
1  0.75  18  1.5  2.1  32  2.6  3.6  36  3.0  4.1  63  5.3  7.1  126  10.5  14.2 
1.5  1.1  27  2.3  3.1  47  3.9  5.3  54  4.5  6.1  95  7.9  10.7  189  15.8  21.4 
2  1.5  37  3.0  4.1  63  5.3  7.1  72  6.0  8.1  126  10.5  14.2  252  21.0  28.5 
3  2.2  55  4.6  6.2  95  7.9  10.7  108  9.0  12  189  15.8  21.4  378  31.5  42.7 
5  3.7  91  7.6  10  158  13.1  18  180  15  20  315  26.3  36  630  52.5  71 
7.5  5.6  137  11  15  236  20  27  270  23  31  473  39  53  945  79  107 
10  7.5  183  15  21  315  26  36  360  30  41  630  53  71  1260  105  142 
15  11  274  23  31  473  39  53  540  45  61  945  79  107  1891  158  214 
20  15  365  30  41  630  53  71  720  60  81  1260  105  142  2521  210  285 
25  19  457  38  52  788  66  89  900  75  102  1576  131  178  3151  263  356 
30  22  548  46  62  945  79  107  1080  90  122  1891  158  214  3781  315  427 
40  30  731  61  83  1260  105  142  1441  120  163  2521  210  285  5042  420  570 
50  37  913  76  103  1576  131  178  1801  150  204  3151  263  356  6302  525  712 
60  45  1096  91  124  1891  158  214  2161  180  244  3781  315  427  7563  630  855 
70  52  1279  107  145  2206  184  249  2521  210  285  4412  368  499  8823  735  997 
80  60  1461  122  165  2521  210  285  2881  240  326  5042  420  570  10084  840  1140 
90  67  1644  137  186  2836  236  321  3241  270  366  5672  473  641  11344  945  1282 
100  75  1827  152  207  3151  263  356  3601  300  407  6302  525  712  12605  1050  1425 
125  93  2283  190  258  3939  328  445  4502  375  509  7878  657  891  15756  1313  1781 
150  112  2740  228  310  4727  394  534  5402  450  611  9454  788  1069  18907  1576  2137 
175  131  3197  266  361  5515  460  623  6302  525  712  11029  919  1247  22058  1838  2494 
200  149  3654  304  413  6302  525  712  7203  600  814  12605  1050  1425  25210  2101  2850 
225  168  4110  343  465  7090  591  801  8103  675  916  14180  1182  1603  28361  2363  3206 
250  187  4567  381  516  7878  657  891  9003  750  1018  15756  1313  1781  31512  2626  3562 
275  205  5024  419  568  8666  722  980  9904  825  1120  17332  1444  1959  34663  2889  3918 
300  224  5480  457  620  9454  788  1069  10804  900  1221  18907  1576  2137  37814  3151  4275 
350  261  6394  533  723  11029  919  1247  12605  1050  1425  22058  1838  2494  44117  3676  4987 
400  298  7307  609  826  12605  1050  1425  14405  1200  1628  25210  2101  2850  50419  4202  5699 
450  336  8221  685  929  14180  1182  1603  16206  1351  1832  28361  2363  3206  56722  4727  6412 
550  410  10047  837  1136  17332  1444  1959  19808  1651  2239  34663  2889  3918  69326  5777  7837 
600  448  10961  913  1239  18907  1576  2137  21608  1801  2443  37814  3151  4275  75629  6302  8549 
Electrical Motor Power, Velocity and Torque Equations
Torque in Imperial units can be calculated as
T _{ inlb } = P _{ hp } 63025 / n (1)
where
T _{ inlb } = torque (in lb_{f} )
P _{ hp } = horsepower delivered by the electric motor (hp)
n = revolution per minute (rpm)
Alternatively
T _{ ftlb } = P _{ hp } 5252 / n (1b)
where
T _{ ftlb } = torque (lb_{f} ft)
 1 ft lb_{f} = 1.356 Nm
Torque in SI units can be calculated as
T _{ Nm } = P _{ W } 9.549 / n (2)
where
T _{ Nm } = torque (Nm)
P _{ W } = power (watts)
n = revolution per minute (rpm)
Electric Motor  Torque vs. Power and Speed
 1 hp = 0.746 kW  power converter
 1 lb ft = 1.355 Nm  torque converter
Electric Motor  Power vs. Torque and Speed
Electric Motor  Speed vs. Power and Torque
Example  Torque from an Electrical Motor
The torque delivered from an electrical motor producing 0.75 kW (750 W) at speed 2000 rpm can be calculated as
T = ( 750 W ) 9.549 / (2000 rpm)
= 3.6 (Nm)
Example  Torque from an Electrical Motor
The torque delivered from an electrical motor producing 100 hp at speed 1000 rpm can be calculated as
T = (100 hp) 63025 / (1000 rpm)
= 6303 < (lb_{f} in)
To convert to poundforce foot  divide the torque by 12 .
Related Topics

Electrical
Electrical engineering with units, amps and electrical wiring. Wire gauges, electrical formulas, motors and more.
Related Documents

Angular Motion  Power and Torque
Angular velocity and acceleration vs. power and torque. 
Electric Motors  IEC and NEMA Standard Torques
IEC and NEMA torque classifications of electrical motors. 
Electric Motors  Torque vs. Power and Speed
Electric motor output power and torque vs. rotation speed. 
Electric Motors  Torque vs. Power and Speed
Electric motor output power and torque vs. rotation speed. 
Electrical Induction Motors  Torque vs. Speed
Full load operating torque vs. break down, pull up and locked rotor torque. 
Electrical Vehicle Charging  Power vs. Voltage and Amps
EV Charging  AC vs. DC, single phase vs. three phase and power vs. voltage and amps. 
Improvised Torque Wrench
Improvise a torque wrench with a luggage scale. 
Induction Motors  No. of Poles and Synchronous vs. Full Load Speed
Synchronous and full load speed of amplitude current (AC) induction motors. 
Rotating Shafts  Torque
Torsional moments acting on rotating shafts. 
ThreePhase Electrical Motors  Power vs. Amps and Voltage
Full load amps, wire and conduit sizes for three phase electrical motors. 
ThreePhase Power  Equations
Electrical 3phase equations. 
Torque  Work done and Power Transmitted
The work done and power transmitted by a constant torque. 
Torque or Moment of Force  Online Converter
Torque or moment  the tendency of a force to rotate an object.