### Power, Speed & Torque Relation

or Torque T = (9545 x Power) / Speed (Torque in Nm, Power in kW, Speed in RPM)

## Torque

It is simply the product of the force acting on the body and the perpendicular distance from the given point to the line of action of the force. Torque is equivalent to a couple acting upon a body.

Torque = Force x perpendicular distance

T = F x *l*

# Power

In Engineering, power is the amount of energy transferred or converted per unit time or simply rate of doing work.

**SI unit:** Watt

# Speed

The rate at which an object covers distance is called time. In this case, the rotational speed which is measured in the Rotations per minute(RPM).

**Tags:**

Sorin Ciolovic says

Hello,

I guess there are some mistakes, in your calculations, please.

For example, I want to calculate the Torque of a motor in these conditions:

– Power=1000 Kw=1Mw;

– Speed=1500 RPM.

T = 60 x 1000 / 2 x 3.14159 x 1500 = 60000 / 9424.77 = 6.3662 Nm.

This is the correct result, not 6369.48 Nm!!!

Please, there are some errors in your calculations: your result is approx. 1000 times more than the correct one!!!

Thank you very much.

Kind regards,

Sorin Ciolovic.

Sundar says

Hello Sorin,

I am afraid I am getting the correct value only… 6369Nm. Can you please cross-check once again… there must be something wrong. can you try again and let me know. immediately…

Sorin Ciolovic says

Hello Sundar,

You gave us two different formulas to calculate the motor torque:

1) Torque (Nm) = 60 x Power (KW) : 2 x 3.14159 x Speed (rpm).

For, let’s say, a motor with P = 1000 KW; and Speed = 1500 rpm, we have:

Torque (Nm) = 60 x 1000 : 2 x 3.14159 x 1500 = 6.366 Nm.

2) Torque (Nm) = 9545 x Power (KW) : Speed (rpm).

For the same motor, we have:

Torque = 9545 x 1000 : 1500 = 6,363 Nm.

As we could observe, there is a BIG DIFFERENCE OF 1,000 TIMES BETWEEN THESE TWO RESULTS!!!

Which is the correct one?

These are the formulas given by you!

I am waiting for your response.

Many thanks,

Sorin Ciolovic.