 Ash
Grove Cement Company
Kiln ID Fan Replacement
Leamington, Utah
After kiln ID fan failures recurred frequently for many years,
Ash Grove Cement Company called on Roberts & Schaefer to find
a solution that would eliminate the significant downtime and lost
productivity from its plant outages.
Ash Grove Cement was faced with a significant capital outlay
for a new DC drive system. However, Ash Grove and R&S discovered
an AC motor and a spare AC starter in the warehouse, and considered
using the AC drive instead. The fan's required modulation was
minimal, and occurred at the top end (from 95 percent to 98 percent)
of the speed range.
R&S studied the effects of running with an AC drive, including
ramp-up time. The fan outlook damper was modified to handle the
expected increased torque. The replacement drive system was tested
during a plant outage, and performed well. As a result, the fan
remained in operation using the AC drive.
Since the AC drive was installed, Ash Grove has seen a production
increase, with no plant outages. Total replacement cost for the
drive was less than $20,0000.
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