Machine Builders and System Integrators are constantly innovating new ways to improve the operational efficiency of plant floors. These innovations are being driven by stringent regulations, tough competition and rising operational & labor costs. The post details some major tips as to how the energy can be conserved in the plant floor.
Machine actuators are often over-sized by machine builders or end-users to widen the safety margin. While it does lead to greater reliability, it also adds up costs. Through proper design, this can be avoided, and greater efficiency can be achieved.
- Compact motors with simpler construction are better than bigger ones
- Improved sizing can help bring down costs during run-time, while lowering initial machine costs as well
- High-efficiency motors may have a high initial cost, but at the same time they have a smaller payback period, usually 1 – 2 years
With that being said, machine builders should also note some constraints while sizing motors:
- The rated voltage should never be exceeded during operation, otherwise there would be an increased risk of damaging the machine and electrocuting the user.
- The rated current should not be exceeded for extended time periods, otherwise the risk of overheating becomes high that can lead to burnt motor windings.
- Induction motors are designed to run faster than the rated speed when loaded lightly, so exceeding the rated speed by a little margin is okay. For instance, an induction motor designed to run at 1450rpm would operate safety up till the synchronous speed, e.g. 1500rpm. Exceeding the synchronous speed increases the risk of mechanical failure due to centrifugal force.
- The rated power shouldn’t be exceeded, except in cases where the motors have a specific service factor defined by the manufacturer. This allows dealing with variable loads, but as a rule of thumb, going over the rated power can lead to overheating and mechanical failure.
- The rated torque is quite often not present on the nameplate. You can calculate it with the following formula:
Exceeding it can lead to burnt out motor windings as well as damage to couplings and drive shaft.
Optimized Motor Control
Ensuring that the motor control mechanism is optimized can cut down energy costs while improving the longevity of the motor.
- Whenever possible, smaller motors must be cascaded, e.g. pumps, compressors and ventilators, so that they can adapt to dynamic loading needs.
- High efficiency motors should be employed, with a potential to cut down costs by 10%.
- Motors should be controlled through variable speed drives for dynamic loads.
- For positioning applications, servo drives should be used, which can increase savings by 30%.
Employing motion solutions can help master movements. There are incredible advantages associated with motion technologies, such as servo motors and motion controllers. When coupled with synchronous motors, they can bring in energy savings. In addition to improving energy savings by 60%, faster machine cycles can help improve output and make the process more precise. Machine designs that are based on mechatronics can lead to lower total cost of ownership as they are highly energy efficient.
The following benefits can be reaped by the OEMs:
- Fewer mechanical components
- Optimized power flow
- Smaller control panels
The benefits for end users are:
- Highly productive machines
- Flexible production
- Compact designs
- Lower energy costs
- Less waste