Background
Power transmission instruments are important to the performance of nearly every piece of machinery as they are being used in numerous important applications. In the automation industry alone, they are utilised in assembly lines, controlling conveyor belts, bottling, packaging and the precise positioning of products, to name just a few.
Therefore, it’s vital that these systems remain reliable, consistent and accurate throughout their lifespan without failure. Although the demand for power transmission products is growing at a steady pace, manufacturers of gear, motor and power transmission equipment are competing on quality, delivery times and high load capacity, which in some cases can be the main reason for breakdowns.
Typically, gearbox manufacturers publish the specified motor output power, which does not always accurately convey the actual gearbox output power. To close the gap between design-estimated and actual gearbox performance, validation on test rigs has become an integral part of the gearbox development process.
The Client
Mellor Electrics offers a wide range of power transmission products including AC, brushless D.C. and geared motors, suitable for a vast range of applications such as vending machines, pellet burning stoves, pumps, catering equipment, scientific equipment and animated displays.
As a leading motor and gear motor manufacturer in the UK, Mellor Electrics have retained most of their processes in-house, maintaining control over various aspects of production. To preserve the reliability of their products, the company invested in the latest CNC turning, hobbing machines, as well as CAD facilities and computerised testing equipment, offering high levels of accuracy, unrivalled quality and reliability.
In-house design and engineering facilities allow Mellor Electrics to maximise product quality, decrease delivery times and make sure that every single piece of the equipment they produce undergoes stringent testing before reaching their customers worldwide, from North America to Australia and Japan.
The Challenge
Gearbox breakdowns are typically characterised by underestimation of operating loads or insufficient testing, including endurance testing, performance testing, static and dynamic overload testing, as well as loading control.
Consequently, most customers now request extensive load testing, with original test results before moving to the production phase. To comply with customer needs, Mellor Electrics were testing several ways of getting precise torque measurements and being able to produce the speed/torque graphs, required by their customer. Formerly, the team used a basic beam rig on the end of an arm, as well as a third-party dynamometer, with the latter being rather overcomplicated for its application.
Looking for an alternative solution online, they sourced the Datum Electronics M425 non-contact rotary torque sensor, which had a proven track-record of being used for motor testing and process control applications.
Solution
The Mellor Electrics team decided to build their own test station, consisting of a power supply (AC, DC and brushless DC), Datum Electronics dynamic torque transducer with software, connected to a laptop, magnetic particle brake and a fixture, manufactured to the required tolerances, connecting these components in line with precision bearings.
The motor gearbox is connected to the rotating M425 torque sensor, which in turn is mounted to the brake. When power is applied to the tested motor gearbox, the brake is applied at a slow and steady rate via a potentiometer. The speed and torque are then logged by the software on the laptop for future analysis and producing a speed/torque curve graph, requested by their customer.
Impact
The cost of gearbox replacements and rebuilds as well as the downtime, associated with these failures, increases the cost of production. To prevent potential failures and decrease the cost of manufacture, it is critical to understand the gear motor’s performance to prevent their failures.
Understanding the importance of having the right drive system in place, Mellor Electrics takes pride in producing high-quality gear motors, supplied with accurate technical documentation for optimal performance.
As a result of these thorough testing procedures, Mellor gained all the relevant output info their customers required. They were able to profile the gear motor’s performance under various loads, noting the motor’s speed, torque and power output, as well as calculating the motor efficiency. The latter then was plotted on a speed/torque graph and used in a datasheet, enabling Mellor Electrics to design future samples for the customers’ requirements, faster and easier.
