Diego,

I found this resource from a previous thread it is the Rosta catalog and it has a lot of good information.

http://www.rosta.ch/mediafeatures/p...7-078ex3.pdf

Does anyone have any calculations for determing input power? I used the calcualtion in this catalog and it seems way too high. ■

The formula I use to determine the minimum size of electric motors on vibrating screens and feeders is:

kW = (mR x N x 1.25) divided by (97,000 x LRT)

where:

kW = design power (kilowatts), and select the next larger standard motor size.

mR = the static moment of the screen exciting mechanism (kg.cm)

N = screen frequency (rpm)

1.25 = a reserve factor to allow for cold weather starts, possible in field machine speed increases, shortcomings in line voltage, wire sizes etc.

LRT = the locked rotor torque of the motor in decimal form. ie: 250% would be 2.5 in the formula.

For vibrating equipment the general recommendation is that the motor should have a min locked rotor torque of about 200%.

For linear motion equipment the result can be reduced by applying a factor depending upon the “angle of attack” of the vibrating stroke – but we wont complicate things with that now.

Cheers ■

John,

How about a formula to calculate the power needed for a crankshaft driven reciprocating feeder? ■