leitmotif
Member
With respect to motors controlled by a VFD
Between O RPM and Baseline
Torque "capacity" motor is equal to that of rated torque.
Voltage is proportional to frequency ie 240/60 or 480/60
RPM is proportional to frequency.
ABOVE baseline -
(let us assume we double baseline speed to keep math simple)
Voltage is held constant
RPM doubles
Torque drops as the inverse of speed change squared ie is now at 1/4 of rated.
IF you crank the data thru HP = (T x RPM) /5252 then HP should halve (2 x 0.25 = 0.5). However manufacturers state that this is constant HP range.
I dont understand this disparity. Can someone explain this to me please?
Dan Bentler
Between O RPM and Baseline
Torque "capacity" motor is equal to that of rated torque.
Voltage is proportional to frequency ie 240/60 or 480/60
RPM is proportional to frequency.
ABOVE baseline -
(let us assume we double baseline speed to keep math simple)
Voltage is held constant
RPM doubles
Torque drops as the inverse of speed change squared ie is now at 1/4 of rated.
IF you crank the data thru HP = (T x RPM) /5252 then HP should halve (2 x 0.25 = 0.5). However manufacturers state that this is constant HP range.
I dont understand this disparity. Can someone explain this to me please?
Dan Bentler