what do electric motor specs mean?

Question

Specifically Watts, Volts, and Amps.  I know Watts is J/s which is how much energy is being used per time, but I do not know how the volts and amps of a battery play into it.  I also know that volts is the difference across the battery terminals and amps is the speed of the current, but how does that effect performance?  i.e. if there are 2 motors with the same watts, what does changing the voltage or amperage do?

billrussell42 · Accepted Answer

And don't forget frequency.

Voltage is a design parameter. A motor is designed to operate at a specific voltage, AC or DC. For example, a motor in an auto would be designed to operate on 12 volts DC. One for a US home would be designed for 120 volts AC 60 Hz. One for a european home would operate on 240 volts AC 50 Hz.

This says nothing about motor power, that is determined by the size of the motor, size of wire, many other parameters. That is another design factor, as the designer adjusts those parameters so that the motor puts out the power needed. 

Power is voltage x current, and is in watts. 746 watts is one horsepower. So if the designer needs a 1/10 HP motor, or 75 watt motor, and he is operating at 12 volts, then he adjusts the various parameters so that the current at full load is 75W/12 volts or 6.25 amps. Or an equivalent resistance of 12/6.25 or 1.92 ohms.

If he needs a similar 75 watt motor to operate at 120 VAC, he designs it for a current of 75/120 or 0.625 amps.

(This is somewhat simplified, leaving out staring current, staring windings, effects of frequency, etc.)

hope this helps.

.

Chandramohan P.R · Answer

Watts is the unit of energy.It is voltage x current.
A motor is designed to work on a particular supply voltage. If U use wrong supply voltage motor will burn or will not run.
Same motor will draw different amount of current depend upon the variable load.
Motors need lot  of current battery will not be sufficient to run them.Only toy motors run on batteries.
746 watts is one horse power.Depend upon the work load U need bigger wattage or H.P
Voltage is also depend upon the size of motor.
If U need to run a 10MVA motor, utility company will not allow u to connect it to a 110 volt system.U need higher voltage supply for such big  motors.

Anonymous · Answer

in case you will use a pulley to land up the string, the motor polarity does not rely, so all you prefer is a twin flex from the mains adapter, that's not appropriate which way you connect the finally ends up in the motor or the adapter. in the journey that your adapter does not have a twin flex popping out of it you will desire to purchase a multiconnector for DC ability aspects and decrease off the only ability jack on the tip of the lead till now utilising the bare ends to connect with the motor. The multiconnector would desire to have one plug which inserts the adapter socket.

what do electric motor specs mean?

3 Answers