Page 15 - Industrial Technology EXTRA - 10th August 2020

take a servo motor with a stall, or holding, torque of mechanism such as belts and pulleys or gearboxes.
7.5Nm and a rated torque of 4.8Nm at 6000rpm But these mechanical devices may have restrictions
as an example. on the speed.
In the case of our pumping example, which shall
Nominal power we say is destined for a production cell operating
You could say that, based on the figures above, the under ATEX conditions, the gearboxes are limited to
power rating of the motor is: nominal power (Pn) = an input speed of 2300rpm. Even though the motor
(nominal torque Mn x Nn nominal speed) / 9550 = specification has rated power at 1.382 kW, the
(4.8Nm x 6000rpm) / 9550 = 3.02 kW. However, power available at 2000rpm is considerably less at
you may be running the motor at 3,000 or 0.84 kW.
4,000rpm. What effect does this have on the power We can operate the pumps well within the
the motor is producing? At 4000rpm the motor will gearbox speed restriction, but this means that we
deliver approximately 5.7 and 6.15Nm at are not utilising the full speed range of the motor,
3000rpm. This would equate to approximately hence we need a higher kW rating than is actually
2.39kW and 1.93kW respectively. required were it not for the ATEX operating
There are a number of ways you can harness the restrictions.
full power of the motor by using a gearing www.motec.co.uk

GO BEYOND – EXPLORE NEW HORIZONS FOR YOUR INDUSTRY.

Overcome the limitations of known systems and leave the beaten path of those who follow. With SICK at your side, you are always
one step ahead. Because intelligent sensor technologies enable better processes and new opportunities for your Industry 4.0
business models. Use trend-setting SensorApps, Deep Learning, and other AI applications, as well as integration and analysis
solutions. Let’s go beyond together. We think that’s intelligent. www.sick.com/gobeyond