Motor and torque calculations
Motor and torque calculations
(OP)
Hi,
I am slightly confused and hope someone can put me straight on this.
Power in W is Shaft torque in Nm * the angular velocity in rad.
So at 195Nm (44lbf) and a shaft speed of 1250rpm I am developing 25619W (25.6kW)
Now when I look at my motor curve …. 44lbf and 1250 rpm …The power curve indicates about 10HP (7.45kW)
Is my motor curve wrong or is it my interpretation of the relationship between Torque and RPM ??
Jan ....
I am slightly confused and hope someone can put me straight on this.
Power in W is Shaft torque in Nm * the angular velocity in rad.
So at 195Nm (44lbf) and a shaft speed of 1250rpm I am developing 25619W (25.6kW)
Now when I look at my motor curve …. 44lbf and 1250 rpm …The power curve indicates about 10HP (7.45kW)
Is my motor curve wrong or is it my interpretation of the relationship between Torque and RPM ??
Jan ....





RE: Motor and torque calculations
http://www.onlineconversion.com/torque.htm
RE: Motor and torque calculations
RE: Motor and torque calculations
TTFN
RE: Motor and torque calculations
1250 RPM = 1250/60 RPS (60 seconds to one minute) and there are 2*PI radians to one revolution. So your speed is 2*PI*1250/60 = 130.8 rad/s
You already have 195 Nm and shaft power is speed times torque or 130.8 * 195 = 25.5 kW, which is wrong.
The 44 lbf (poundfoot? I think poundforce, so the torque arm is missing) translates into 1.36*44 = 59.7 Nm. So your shaft power should be something like 130.8 * 59.7 = 7.81 kW, which agrees quite well with your "about 7.45 kW".
RE: Motor and torque calculations
Yes my mistake was the "ft/lb" to Nm conversion I did first...
Now it all makes sence ...