All it took was a little ingenuity and a flexible drive for a fan and blower manufacturer to upgrade its testing equipment. Here's how the company did it.
The New York Blower Co. (NYB) in La Porte, IN, designs and builds fans and blowers for commercial and industrial applications such as ovens and pollution control systems. Since its inception, the company has relied on innovative product testing to keep pace with the changing needs of its projects.
A dilemma occurred when NYB started receiving requests for 50 Hz fans and blowers. That meant the company needed to develop a fan and blower test stand that had the capability to test variable frequencies. However, no test stand on the market offered such a capability. So NYB officials sought a different solution.
The company contacted Quality Industrial Services (QIS), a systems integrator also based in La Porte, to help develop a test stand using a variable frequency ac drive that could test both the 50 Hz and North American 60 Hz ratings. The solution developed by QIS involved a system integrating an ac drive, an industrial operator interface, and a powerful processor designed to ease operator use. QIS also worked to increase testing cycle time and aided NYB in conforming to markets other than North America.
Testing For Performance
Previous testing methods had several disadvantages that NYB directly addressed when designing the new test stand. In the past, fan and blower motors were tested using across-the-line starters with simple 220, 440, and 575 V output transformers activated by a start/stop button. The new test stand consisted of four separate power leads from four 220 and 460 V boxes, each with its own set of fuses.
In addition to providing variable hertz testing capabilities, NYB and QIS aimed to design a new machine that would offer current limiting features and also would be portable, eliminating time-consuming inter-plant product transport. The final solution included an Allen-Bradley 1336 Plus ac drive with variable frequency control, a PanelView operator interface, and an SLC-5/03 processor.
"The main reason we wanted the drive was to be able to portably test 50 Hz fans and motors along with our standard 60 Hz products," says James Malkemus, a manufacturing engineer at NYB. "When we installed the drive on the test stand, we discovered we could do a lot more than just regulate frequency. We were able to increase operator ease of use, add motor-testing flexibility, improve testing cycle time, and improve safety."
Getting Operators On-Board
To be effective, the test stand needed to be operator friendly. Operators can choose testing parameters from the PanelView menu, allowing them to vary up to 12 preset parameters such as voltage, frequency, ramp-up and ramp-down times, current limits, and overloads. The messages are relayed from the PanelView menu through the SLC-5/03 processor to the drive. All commands are instantly verified to ensure safe, accurate operation.
The new system allows operators to select required hertz during testing, solving NYB's original need for 50 and 60 Hz testing requirements. The test stand's design led to quick operator acceptance and increased testing capabilities, according to the company.
"When we installed the new test stand, very little operator training was required," Malkemus says. "Operators quickly understood how to use the system, due in large part to the menu-driven operator interface. In addition, it offered a safer alternative than our old methods."
Previous testing methods involved starting motors across the line, which created potentially high levels of current and very high levels of voltage. If power leads were accidentally dropped on the ground, a serious threat of flash and burn could occur. With the new test stand, operators can ramp up to set voltages, providing a safer testing environment by controlling power lead amperage.
Expanding Testing Flexibility
The engineers working on the project also added testing flexibility and improved cycle times by taking advantage of the 1336 Plus drive's current limiting capabilities. Engineers at NYB are able to set a time at which the drive can ramp up to a preset amperage, instead of simply connecting power to the fan and blower motor. The system is designed so that it can automatically create the current limit based on the horsepower and voltage. Operators only need to enter frequency.
The ramp-down feature of the 1336 Plus also adds value to NYB, according to Malkemus. Previously, fans and blowers had to coast to a stop, which often took several minutes. Since operators would start and stop motors many times during testing, precious testing time was lost as operators waited for rotating parts to completely stop. Now, operators can enter ramp-down times to command the drive to brake the fans and blowers so that they stop more quickly, significantly decreasing testing cycle times.
"The reason we chose the 1336 Plus was for its frequency-varying capabilities and we found out that there were a lot more advantages, especially with the current limiting that we can actually control," Malkemus says.
The new portable test stand quickly became popular among operators at NYB's facilities. As a result, 12 months after the 125-hp stand was first used on the floor, NYB added two additional test stands, another with a 125-hp 1336 Plus drive and one with a 250-hp 1336 Plus drive. Now, operators at each of NYB's plant buildings can take advantage of the test stands' variable frequency features, faster cycle times, and ease of use – resulting in increased product quality and throughput as well as helping NYB compete in the worldwide market.
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