Steel industry professionals greeted the second presentation delivered by Richard Warriner, the president of Fort Worth, Texas-based crane component specialist Flow in Motion LLC, to the Association for Iron & Steel Technology’s (AIST) Crane Symposium, which took place last month (June) in Pittsburgh, Pa.
Having delivered a presentation titled Cab Design Considerations during the early throes of the event, Warriner returned to the stage to explore crane motors with plant maintenance staff; applications, electrical, mechanical, safety, service and design engineers; operations and maintenance personnel and management; and those who supply parts, equipment and services to the steel industry.
It was the ninth occasion that Warriner has addressed delegates at the annual event, which took place for the 22nd time this year. His second paper focused on crane motors and the trend of DC controls being replaced by new, sophisticated AC controls.
Warriner’s paper outlined the advantages of new equipment—Flow in Motion provides a range of components from industry leading manufacturers, including motor specialist Woelfer Motoren, of Germany—and talked delegates through the upgrade process.
Attendees heard how solid-state AC controls have fewer mechanical components that can be susceptible to wear and tear, whilst requiring frequent maintenance. Warriner explored other advantages such as direct power generation from the AC source; no loss of efficiency through conversion; greater versatility; inherent diagnostics for rapid trouble-shooting and repair; and many more.
The crane industry veteran, who has overseen the installation and use of electric overhead traveling cranes and other lifting equipment in steel applications for decades, went on to explain how the cost of owning DC drives is becoming less economically viable.
Warriner said: “As demand lessens, manufacturers are reducing production of obsolete parts. Thus, availability and selection of new parts and equipment is becoming more difficult to acquire. At the same time, personnel skilled in designing and maintaining the old systems are retiring.”
Crane Symposium delegates were given guidance by Warriner as to the most efficient way to reduce costs when replacing motors designed for a dated system with those compatible with new, technologically advanced equipment.
“New motors must meet existing torque and inertia characteristics of the beloved old style DC mill motors,” he said. “Users can reduce costs by keeping the other existing power train components, such as gear reducers, mounting platforms and motor brakes.”
He alluded to a common mistake he sees in the field whereby users take a low-cost, standard catalog AC motor and try to make it “fill the shoes” of a DC mill motor. Problems spiral from different torque and inertia characteristics changing the operating dynamics, for example.
Warriner closed his paper with an exploration of the characteristics of motors.
Other components in the Flow in Motion range include operator seats and cabs; severe duty air conditioners for severe environments; trolley hoists; and end trucks, the majority of which are custom solutions.