16
Danger
Please utilise extreme caution when performing work within the compressor. Wear
appropriate PPE
(Personal Protective Equipment)
, follow
lock out-tag out
procedures, and
ensure all safety procedures
.
“
USER 1” FAULT – GENERAL INFORMATION
•
What is the “USER 1” fault?
The compressors are fitted with one or two thermal sensors (depending on the generation of the
compressor) to detect any overheating and stop the unit when the temperatures are over the limits.
–
Phase I and Phase II units : only one sensor (HATS switch) on the compressor itself
–
Phase III units : HATS switch plus a thermal sensor within the motor
The drive trips on “User 1” anytime one sensors is trigged.
Note : On Phase III units, the two sensors are in series, which means that the drive trips on “User 1”
anytime one of these two sensors opens.
In practice, what can lead the drive to trip on “User 1”?
The drive trips on “User 1” to protect the units from overheating. Anyhow, several other issues might lead
to such trip.
–
Defective sensors (HATS switch and/or thermal sensors in the motor)
Î
sensor trips even though
the temperatures are still below the limit
–
Wiring issues or loose connections within the drive (harness connected to the drive) or with the
HATS switch or with the thermal sensor in the motor
•
Importance of knowing the frequency of “User 1” fault.
Depending on the frequency with witch the drive trips on “User 1”, we can consider that some explanations
are more likely than others.
–
If there is a problem with the wiring, the connections, or the sensors themselves, we can expect
the drive to trip almost continuously or at least several times an hour.
–
If there is a problem with the cooling, we can expect the drive to always trip after several minutes,
when the temperatures exceed the threshold limits.
–
If the drive trips only few times a week or less, the compressor might actually exceed the
temperatures from time to time
After opening, it takes several minutes for the HATS switch and the motor thermal
switch to close – The drive keeps tripping on “User 1” if attempt is made to restart
the compressor during this period of time
Appendix 2
