Table 3: Safety shutdowns
Message
Description
VSD - Precharge Lockout
PRE-CHARGE FAULT LOCKOUT
If the OSCD fails to meet the precharge criteria (refer to precharge faults), the
precharge circuit waits for a period of 10 seconds before another precharge
attempt. The unit’s cooling fans and coolant pump remain energized during this
time period. Following this 10-second period, the precharge is initiated again. The
unit attempts to meet the precharge criteria three consecutive times before the
OCSD shuts down, locks out, and displays this message.
A thermistor sensor is located inside the transistor module on the harmonic filter
power unit. If at anytime this thermistor detects a temperature higher then the
threshold value a shutdown will occur. See the following chart for the shutdown
threshold values. A manual reset is required by pressing the “Overtemp Reset”
pushbutton located on the Filter Logic board.
Drive hp rating
Threshold shutdown value
270, 292, 351
175°F (79°C)
385, 419, 424, 503, 608 (575 VAC)
190°F (88°C)
608 (400 VAC), 704, 658, 790
194°F (90°C)
Harmonic Filter - High Baseplate
Temperature
HIGH FILTER BASEPLATE TEMPERATURE
FAULT
868, 882, 914, 917, 948, 1055
175°F (79°C)
Harmonic Filter - High Total Demand
Distortion
FLTR HIGH TDD FLT
The control center determines this shutdown by using data supplied from the
harmonic filter logic board. This shutdown indicates that the filter is not operating
correctly or the input current to the OSCD/filter system is not sinusoidal. This
shutdown will occur if the Total Demand Distortion (TDD) in any one phase
exceeds 25% continuously for 45 seconds. TDD is defined by the IEEE Std 519-1992
standard as “the total root - sum - square harmonic current distortion, in percent
of the maximum demand load current (15 or 30 min demand)”. The harmonic
filter option was designed to provide an input current TDD level of 8% or less for
the OSCD system. A standard OSCD less the optional filter typically has an input
current TDD level on the order of 28% to 30%.
Liquid-Cooled OptiSpeed Compressor Speed Drive
36
