Calculation of torque of a DC motor

[fawaaz]

Hi everyone,

Im currently doing my final year project and I need to calculate the torque of a DC motor so that I can replace it accordingly by another motor. Here are the motor's specification : 400V, 50Hz, 6poles, 200kW, 1400rpm, 371A
Can anyone please help me sort this out.

regards,
Fawaaz

 

[tvavanasd]

I think the RPM (or number of poles) listed is incorrectk assuming specs above are for an induction motor.
A 6 pole motor at 50 Hz should give about 1000 rpm synchronous. With 1% slip, you should expect about 990 rpm.
50 Hz with 4 poles gives 1500 rpm synchronous. The motor would have to slip over 6% to make 1400 rpm.

 

[fawaaz]

oooh god... i made a mistake... itz 1000rpm... :(

now u can calculate the torque??

 

[jloram]

You know the power (200kw) and you know the rpm (1400). Open any first year physics book and look up the relationship between hp-rpm-torque.

 

[alphy]

Hello Fawaaz,

Calculating the torque of a DC motor is an important step in understanding its performance and determining if it is suitable for your project. To calculate the torque, you will need to use the formula:

Torque = (Power x 60) / (2 x pi x Speed)

In this case, the power is given as 200kW and the speed is 1400rpm. Converting 1400rpm to radians per second (rad/s) by multiplying by 2 x pi / 60, we get a speed of 146.67 rad/s.

Plugging these values into the formula, we get:

Torque = (200,000 x 60) / (2 x 3.14 x 146.67)
= 1228.6 Nm

This means that the DC motor is capable of producing a torque of 1228.6 Nm. You can use this value to compare it with the torque requirements of your project and determine if it is suitable.

Additionally, you may also need to consider the torque constant (Kt) of the motor, which is a measure of the motor's ability to convert electrical energy into mechanical energy. It is usually provided by the manufacturer and can be used to calculate the torque produced by the motor at a specific current.

I hope this helps you in your project. Good luck!