Cressall Resistors rebuilt a three-section resistor on a limestone crusher at the Ketton cement plant in Rutland, UK, within a week, after the resistor had failed and shutdown limestone crushing operations.
“Ketton Cement got in touch to say that the three-section speed control resistor on the main 2.7 MW crusher motor had failed and asked what to do,” said Martin Nicholls, Sales Director at Cressall. “The resistor operates at 2.2 kV, conducting a 735 A current through a resistance of 0.16 ohm to dissipate 97 kW of heat energy.”
The resistor had been originally supplied in 1985 by Cutler Hammer. Fortunately, Cressall had the original drawings and the right resistor material in stock, Nicholls continued.
After receiving the call from the Ketton plant on Friday, the company made 12 replacement hi-temperature resistor banks to the original specifications over the weekend. On Monday, the insulating boards were delivered from its supplier, Presspahn, which had also worked over the weekend, along with the broken resistor.
“We stripped, rebuilt and returned [it] to Ketton Cement the next day,” said Nicholls.
The plant received the new resistor on the Tuesday after the failure and had returned the crusher to operation before the buffer stock of limestone had been used up – thus avoiding any loss of production at the plant.
Established in 1928, Ketton cement plant, part of Hanson UK, produces over 1 million tpy of cement.
Read the article online at: https://www.worldcement.com/europe-cis/20022017/cressall-supplies-resister-to-keep-ketton-running/