Continous power dc motor

[anonymouse]

Hello to all, can any kind soul point me in the right direction to measure or mathematically calculate the continuous power of a brushed (dont know if that is relevant or not) dc motor. The motor manufacturer only lists its power output as peak power and does not reply to my queries sent. I have a motor rated at 350 Watts peak which i wish to use in a pic based project but under uk law i am allowed 250 Watts continuous.
Many thanks for any suggestions
oscar
(2 spelling mistakes, old english teacher would go mad)

[Dave]

anonymouse, W = I x E, or Wattage = Current x Voltage...

Dave Purola,
N8NTA

[anonymouse]

anonymouse, W = I x E, or Wattage = Current x Voltage...

Dave Purola,
N8NTA

Thanks for the reply, I was interested to know how continuous power of a motor is derived (formula perhaps).Is the peak power of a motor measured under un/loaded conditions, if their are other parameters in calculating the continuous power of a motor, i.e derating factors for continous use,heat dissipation etc. Similar factors to working out the csa of a conductor, but using the motors rated peak power as that is all I have to work from.
cheers

[mackrackit]

Are you able to run the motor under the given load as a test?
If so then measure the amps.

The load will determine the amps.

[anonymouse]

Are you able to run the motor under the given load as a test?
If so then measure the amps.

The load will determine the amps.

My problem is Dave that by the nature of a dc motor the motor current reduces to zero as the rpm increases due to the back emf, so the current is non linear (motor will be at various pwm from 0 to 100). Thus I am not sure how manufacturers come to derive the continuous power. I understand that peak power can be upto 5x continuous power depending on manufacturer, and I cannot work back to the motor constant (to see if their are equivalents) as I am missing peak torque data.
Thanks for your reply

[aratti]

as I am missing peak torque data.

350 watt seconds (Wsec) is equal to 350 newton meters (N-m)

Al.