John Guthrie, Energy Efficiency Manager, ABB writes: It sometimes seems as if pumps and fans are the only applications for variable-speed drives (VSDs). Of course they are important, but they are not the be all and end all of what drives can do.
Take the fabric industry for instance. WSP Textiles was faced with a problem with the control system of one of its spinning machines, used to produce a continuous yarn for billiard and snooker tables, as well as cloth for many well-known tennis ball brands such as Slazenger and Dunlop.
The problem was the obsolete nature of the speed controls used by the spinning machine. The motor ran at full power constantly, with the speed of the spinning machine controlled via a system of variable diameter pulleys. As well as being inefficient, the system suffered many mechanical failures. As you’d expect, spare parts were also increasingly difficult to find.
Breakdowns every fortnight, each of which took a whole day to put right, meant that production time was on the floor and costs were going through the ceiling. The company also had to have certain parts specially made, adding to the cost. Something had to be done.
The answer was to call on the services of ABB authorised value provider, APDS, to provide a solution. “We chose APDS because they are a local supplier, are very competitive and could supply a product that fitted our needs. We have found their customer service excellent. They are very customer focused and know what engineers need.”
Alan Jones of APDS says: “We selected an ABB high efficiency motor with an ACS550 IP21 drive. WSP fitted the VSD itself, with commissioning support from ourselves. Following the first project, three more machines have been converted to VSD operation, with WSP carrying out all commissioning.”
Harnden wanted a fit and forget solution, so the ABB drive fitted the bill perfectly. “The ABB ACS550 fitted into our old control panel and we could pick up the original signals. The drive just slotted in, making it very easy and quick to connect up –other vendors’ solution simply would not fit the panels we had. This would have required extra expense and time as new panels would take a week to fit, while the ABB drive was fitted in two days.”
Says Harnden: “There have been some energy savings but the biggest benefit for us is that there is no down time since the drive was installed. We have had no need to think about them and no spare parts are needed.”
The company is achieving better production quality as the ability to vary the speed allows them to adjust the tension of the yarn, giving a more controllable stop. This is gentler to yarn and avoids the tangling of the yarn that occurred on the previous method.
Adds Harnden: “VSDs have definitely come into their own and we would now fit them in place of a gearbox solution every time.”
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