Troubleshooting A Problem That Appears Unexplainable - Frick QUANTUM Maintenance Manual

S90-010 M
Page 14
TROUBLESHOOTING A PROBLEM THAT
APPEARS UNEXPLAINABLE
When there is a problem that makes no sense due to
unexplainable things happening, then check the following:
1. It is important to know if the unit ever worked
properly.
2. If the unit used to work properly, try to determine
when the problem first showed up.
3. It is important to know if the problem occurs
randomly, frequently, or all the time.
4. Check what the temperature is in the engine
room and at the panel. Is it very hot or very cold?
·
Make sure that the motor is not blowing
exhaust air on the control panel.
5. If it just started to act up, then check if there was
recently a severe lightning storm, fire, flood, or a
plant accident. If any of the following conditions
are possible, then check for it:
· Has any water, refrigerant, or oil leaked into
the panel or conduit?
·
Is the conduit with the Slide Valve or Slide
Stop full of liquid?
· Is the Slide Stop potentiometer cover filled
with water?
6. If it just started to act up, then check if anything
was recently changed in the system (i.e. software
or hardware.)
7. If it just started to act up, then check if any
service was recently done to the compressor or
it's electrical system?
8. If there is communication wiring connecting the
panel to another panel or device, then check the
following:
·
If the Quantum is unexplainably shutting
down, try disconnecting the communications
cable to see if the problem goes away.
· Check if the communications cable shields
are tied to machine ground at only one
location. For a PLC or Opto22 based
system, the shield should normally be tied
only at the PLC or Opto22 panel. For dual
sequencing machines, the shield should only
be tied to ground in one panel, typically the
"Lead" machine.
·
Check that
recommended communications cable. See
manual to match proper cable with type of
communications (i.e., RS-422, RS-232, RS-
485, or some
communication bus system.)
9. If this is an older plant, has the plant wiring been
brought up to code?
10. Do you have power wiring mixed with control
wiring?
11. Do you have power wiring mixed with sensor
wiring?
12. Do you have
communications wiring?
13. Check that the starter panel is grounded to the
plant transformer. There are usually four wires: 3
for the 3 phases and 1 for plant ground.
FRICK QUANTUM COMPRESSOR CONTROL PANEL
you are using the Frick
other type of factory
power wiring mixed with
MAINTENANCE
14. Check that the motor is grounded to the starter
panel. There are usually four wires: 3 for the
phases and 1 for ground.
15. Ensure that one side of the motor current
transformer is grounded in the motor starter
panel. The wire to the control panel terminal #2 is
usually the only one grounded.
16. Check that the pressure transducers are properly
grounded. The two types of transducers you may
have are as follows: an older type has an 8 to 10
inch 3-conductor pigtail coming out of the
transducer. This type will have the attaching
cable's shield cut off and insulated at the
transducer end. The shield is then tied to a panel
ground terminal in the panel. The newer type has
the cable as an integral part of the housing and
has the shield crimped to the case at the
transducer end. This type of transducer has the
cable's shield cut off and insulated in the control
panel.
17. Check that the temperature transducers are
properly grounded. The temperature probes
usually have two short wires coming out of the
sensor, and are tied to a shielded cable at the
thermal well head. The shield is grounded at the
temperature probe and insulated at the panel
end.
18. Check if one of the temperature probes has a
signal wire shorted to machine ground. To do
this, first pull the orange plug from the micro
board and then use an Ohmmeter and check
each white wire to machine ground and each
black wire to machine ground.
19. Check that all inductive loads (i.e. Coils,
Solenoids, or Relays, etc.) connected to the I/O
output modules have surge suppressers across
them, preferably at the devices and not at the
panel end.
20. If the compressor control settings unexplainably
change modes, it may be a noise problem
affecting the keypad's input circuit. Check if it
works OK with the keypad cable disconnected. If
it works OK, then check the grounding as
described above. If the grounding is OK then
replace the keypad.
21. Make sure that you have a continuous ground
back to the power source. The ground connection
must be aluminum or copper. A conduit ground
will not work. Do not drive a ground stake at the
compressor since extraneous currents will be
attracted to the compressor.
22. Make sure that there is no AC wiring lying next to
the printed circuit board.
23. Unexplainable compressor auxiliary failures are
usually indicative of noise due to wiring problems
(i.e. incorrect earth grounds, mixed power and
control wiring, unsuppressed coils, etc)
24. If the compressor is unexplainably shutting down,
check if the machine shares control transformer
power with something else. Make sure each
compressor has its own isolation transformer in
the motor control center off of the three-phase
bus with the secondary properly grounded.