0
\$\begingroup\$

What does the watts specification on a motor mean?

For example, there are motors with "power: 1500 watts" written on them. Does this mean that motor is capable of output power of 1500 watts?

And what is an 'LBC 05' series motor?

And if I wanted to drive two wheels of a car (x kg car) what are the factors that I will need to keep in mind while selecting the motor? Does the car weight matter?

Thank you. I am a newbie to this and trying to build an electric car :) Any help will be appreciated.
EDIT : P.s Please what are poles of a motor ?

\$\endgroup\$
  • 3
    \$\begingroup\$ What did your google search reveal? \$\endgroup\$ – winny Dec 24 '17 at 11:13
  • \$\begingroup\$ The "What are poles of a motor" edit should be a separate question but there is no need to ask here as there are thousands of articles about it on the web. \$\endgroup\$ – Transistor Dec 30 '17 at 14:13
6
\$\begingroup\$

International standards require the rated output mechanical power to be marked on a motor's rating plate. That would suggest that a motor with "1500 watts" marked on it should be capable of delivering 1500 watts of mechanical power to a load. However there is no guarantee that any particular motor conforms to international standards un less the literature or rating plate indicates that the motor conforms to IEC, NEMA or some other international standard. There may be also a marking on the motor that indicated whether or not it is rated for continuous duty. A 1500 watt motor rated for continuous duty should be capable of delivering 1500 watts of mechanical power 24 hours per day, 365 days per year.

A motor's frame size usually designates the physical dimensions, particularly the mounting and shaft dimensions. A given motor frame size can accommodate a range of speed, and power ratings. The torque rating for a given frame size may vary, but over a smaller range than the speed and power ratings.

\$\endgroup\$
  • \$\begingroup\$ To finish that thought though, the rating is the MAXIMUM power capacity of that motor. How much power it actually produces / consumes is based the connected load. Then when the motor is putting out all 1500W of mechanical power, the actual ELECTRICAL consumption will be higher based upon the efficiency rating of the motor. So for example if that motor is 80% efficient, the electrical consumption at 1500W mechanical output will be 1875W. Without knowing the efficiency of the motor, you cannot accurately predict the electrical power consumption. \$\endgroup\$ – J. Raefield Dec 27 '17 at 20:50
2
\$\begingroup\$

Yes, the weight, or rather the mass, of the car matters.

If you plan on only running over a flat surface the gravitational weight will still affect the friction of the bearings. If you plan on climbing hills, that weight becomes a direct load proportional to the slope.

Even if you have great bearings and are only ever going to drive over a flat floor, the mass of the car dictates how quickly you can accelerate and brake.

Whether or not the reported power translates into mechanical power is something you need to determine from the motors spec sheet and your application. When it comes to an application like this the torque curve is much more relevant since how much power you need will be dictated by how much the motor has to push or pull.

The math for all of that is rather complicated.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.