VFD FRI/EMI - 05/02/06 01:49 PM
outside in the tower yard approx. 40 ft. from
the drives which are in the chiller mechanical room. The copper
sampling pipe is grounded immediately upstream from the meter to the
tower earth ground arrestor system. At the meter location the TDS can
drift by as much as 1000 in a three hour period. Using a second
Lakewood and sensor placed in the tower basin we have found that the
the effect is still present but to a lesser degree. The closer you
move the second meter toward the first the greater the deviation. No
new equipment has been added and the system has been running trouble
free for over six years. Lakewood pronounced the meter to be in
perfect working order. Has anyone had any similar experiences? Any
input is appreciated.Thought of the RF issue but consider it unlikely
to be radiating from the cabinets. Why would both units develop the
same problem at the same time? Both units individually create the
same issue when the other is off line. What about a high impedance
ground connection? Wouldn't that have the effect of allowing noise
from the drive to radiate from the power leads instead of draining it
away? If so would the connection be local or might it extend back
toward the service entrance through the various MCC's? I'll contact
our electrical contractor for input, but what tests or procedures
should be implimented to track down this problem?
the drives which are in the chiller mechanical room. The copper
sampling pipe is grounded immediately upstream from the meter to the
tower earth ground arrestor system. At the meter location the TDS can
drift by as much as 1000 in a three hour period. Using a second
Lakewood and sensor placed in the tower basin we have found that the
the effect is still present but to a lesser degree. The closer you
move the second meter toward the first the greater the deviation. No
new equipment has been added and the system has been running trouble
free for over six years. Lakewood pronounced the meter to be in
perfect working order. Has anyone had any similar experiences? Any
input is appreciated.Thought of the RF issue but consider it unlikely
to be radiating from the cabinets. Why would both units develop the
same problem at the same time? Both units individually create the
same issue when the other is off line. What about a high impedance
ground connection? Wouldn't that have the effect of allowing noise
from the drive to radiate from the power leads instead of draining it
away? If so would the connection be local or might it extend back
toward the service entrance through the various MCC's? I'll contact
our electrical contractor for input, but what tests or procedures
should be implimented to track down this problem?